<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified" version="0.6.50">
	<xsd:annotation>
		<xsd:documentation>
		**********************************************************************  Overview  **************************************************************
			Definition: 			Controlled vocabulary schema for DLESE metadata frameworks
			Framework use: 	ADN-I (item)
			Source org:			American Association for the Advancement of Science (AAAS); http://www.aaas.org/
			Vocab values:		http://www.project2061.org/tools/benchol/bolframe.htm
			Vocab last update:	
			DPC last update:		2003-02-10
			Notes: 				This is physical setting.	
		</xsd:documentation>
	</xsd:annotation>
	<xsd:annotation>
		<xsd:documentation>*** LICENSE INFORMATION *****
		Copyright 2002, 2003 DLESE Program Center
		University Corporation for Atmospheric Research (UCAR)
		P.O. Box 3000, Boulder, CO 80307, United States of America
		email: support@dlese.org. 
These schemas are free software; you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.  These schemas are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this project; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA  
		</xsd:documentation>
	</xsd:annotation>
	<xsd:annotation>
		<xsd:documentation>*********************** History of Change
2003-02-10:Added comments below to indicate where changes exist between AAAS website and DPC XML schema encoding.
2003-02-10:Learned there more new benchmarks that are not on the AAAS website. Not dealing with those yet.
		</xsd:documentation>
	</xsd:annotation>
	<xsd:annotation>
		<xsd:documentation>***********************  Simple Types (alpha order) *************************************</xsd:documentation>
	</xsd:annotation>
	<xsd:simpleType name="AAAScontentPhysicalType">
		<xsd:annotation>
			<xsd:documentation>
				***************************************  AAAScontentPhysicalType  ***************************************
				Lists the values that will appear in the metadata record
			</xsd:documentation>
		</xsd:annotation>
		<xsd:restriction base="xsd:string">
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:K-2:There are more stars in the sky than anyone can easily count, but they are not scattered evenly, and they are not all the same in brightness or color."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:K-2:The sun can be seen only in the daytime, but the moon can be seen sometimes at night and sometimes during the day. The sun, moon, and stars all appear to move slowly across the sky."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:K-2:The moon looks a little different every day, but looks the same again about every four weeks."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:3-5:The patterns of stars in the sky stay the same, although they appear to move across the sky nightly, and different stars can be seen in different seasons."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:3-5:Telescopes magnify the appearance of some distant objects in the sky, including the moon and the planets. The number of stars that can be seen through telescopes is dramatically greater than can be seen by the unaided eye."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:3-5:Planets change their positions against the background of stars."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:3-5:The earth is one of several planets that orbit the sun, and the moon orbits around the earth."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:3-5:Stars are like the sun, some being smaller and some larger, but so far away that they look like points of light."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:6-8:The sun is a medium-sized star located near the edge of a disk-shaped galaxy of stars, part of which can be seen as a glowing band of light that spans the sky on a very clear night. The universe contains many billions of galaxies, and each galaxy contains many billions of stars. To the naked eye, even the closest of these galaxies is no more than a dim, fuzzy spot."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:6-8:The sun is many thousands of times closer to the earth than any other star. Light from the sun takes a few minutes to reach the earth, but light from the next nearest star takes a few years to arrive. The trip to that star would take the fastest rocket thousands of years. Some distant galaxies are so far away that their light takes several billion years to reach the earth. People on earth, therefore, see them as they were that long ago in the past."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:6-8:Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits.  Some planets have a great variety of moons and even flat rings of rock and ice particles orbiting around them.  Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris."/>
			<!--In the next benchmark, the phrase 'atmosphere and' originally had an m-dash between the words atmosphere and and. The m-dash was changed to a space because then an entity reference does not need to be used in the XML and a space is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:6-8:Large numbers of chunks of rock orbit the sun. Some of those that the earth meets in its yearly orbit around the sun glow and disintegrate from friction as they plunge through the atmosphere and sometimes impact the ground.  Other chunks of rocks mixed with ice have long, off-center orbits that carry them close to the sun, where the sun's radiation (of light and particles) boils off frozen material from their surfaces and pushes it into a long, illuminated tail."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:9-12:The stars differ from each other in size, temperature, and age, but they appear to be made up of the same elements that are found on the earth and to behave according to the same physical principles. Unlike the sun, most stars are in systems of two or more stars orbiting around one another."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:9-12:On the basis of scientific evidence, the universe is estimated to be over ten billion years old. The current theory is that its entire contents expanded explosively from a hot, dense, chaotic mass. Stars condensed by gravity out of clouds of molecules of the lightest elements until nuclear fusion of the light elements into heavier ones began to occur. Fusion released great amounts of energy over millions of years.  Eventually, some stars exploded, producing clouds of heavy elements from which other stars and planets could later condense. The process of star formation and destruction continues."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:9-12:Increasingly sophisticated technology is used to learn about the universe. Visual, radio, and x-ray telescopes collect information from across the entire spectrum of electromagnetic waves; computers handle an avalanche of data and increasingly complicated computations to interpret them; space probes send back data and materials from the remote parts of the solar system; and accelerators give subatomic particles energies that simulate conditions in the stars and in the early history of the universe before stars formed."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The universe:9-12:Mathematical models and computer simulations are used in studying evidence from many sources in order to form a scientific account of the universe."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:K-2:Some events in nature have a repeating pattern. The weather changes some from day to day, but things such as temperature and rain (or snow) tend to be high, low, or medium in the same months every year."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:K-2:Water can be a liquid or a solid and can go back and forth from one form to the other. If water is turned into ice and then the ice is allowed to melt, the amount of water is the same as it was before freezing."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:K-2:Water left in an open container disappears, but water in a closed container does not disappear."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:3-5:Things on or near the earth are pulled toward it by the earth's gravity."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:3-5:Like all planets and stars, the earth is approximately spherical in shape. The rotation of the earth on its axis every 24 hours produces the night-and-day cycle. To people on earth, this turning of the planet makes it seem as though the sun, moon, planets, and stars are orbiting the earth once a day."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:3-5:When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:3-5:Air is a substance that surrounds us, takes up space, and whose movement we feel as wind."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:We live on a relatively small planet, the third from the sun in the only system of planets definitely known to exist (although other, similar systems may be discovered in the universe)."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:The earth is mostly rock. Three-fourths of its surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin blanket of air. It is the only body in the solar system that appears able to support life. The other planets have compositions and conditions very different from the earth's."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:Everything on or anywhere near the earth is pulled toward the earth's center by gravitational force."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:Because the earth turns daily on an axis that is tilted relative to the plane of the earth's yearly orbit around the sun, sunlight falls more intensely on different parts of the earth during the year. The difference in heating of the earth's surface produces the planet's seasons and weather patterns."/>
			<!--In the next benchmark, the phrase 'earth, the' originally had an m-dash between the words earth and the. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:The moon's orbit around the earth once in about 28 days changes what part of the moon is lighted by the sun and how much of that part can be seen from the earth, the phases of the moon."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:Climates have sometimes changed abruptly in the past as a result of changes in the earth's crust, such as volcanic eruptions or impacts of huge rocks from space. Even relatively small changes in atmospheric or ocean content can have widespread effects on climate if the change lasts long enough."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:The cycling of water in and out of the atmosphere plays an important role in determining climatic patterns. Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow, and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the ocean."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:Fresh water, limited in supply, is essential for life and also for most industrial processes. Rivers, lakes, and groundwater can be depleted or polluted, becoming unavailable or unsuitable for life."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:Heat energy carried by ocean currents has a strong influence on climate around the world."/>
			<!--In the next benchmark, the phrases 'but, for' and 'purposes, the' originally had an m-dash between the but and for and purposes and the. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:Some minerals are very rare and some exist in great quantities, but, for practical purposes, the ability to recover them is just as important as their abundance. As minerals are depleted, obtaining them becomes more difficult. Recycling and the development of substitutes can reduce the rate of depletion but may also be costly."/>
			<!--In the next benchmark, the phrases 'resources, such' and 'trees, can' originally had an m-dash between the resources and such and trees and can. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:6-8:The benefits of the earth's resources, such as fresh water, air, soil, and trees, can be reduced by using them wastefully or by deliberately or inadvertently destroying them. The atmosphere and the oceans have a limited capacity to absorb wastes and recycle materials naturally. Cleaning up polluted air, water, or soil or restoring depleted soil, forests, or fishing grounds can be very difficult and costly."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:9-12:Life is adapted to conditions on the earth, including the force of gravity that enables the planet to retain an adequate atmosphere, and an intensity of radiation from the sun that allows water to cycle between liquid and vapor."/>
			<!--In the next benchmark, the phrase 'fall and' originally had an m-dash between fall and and. The m-dash was changed to a space because then an entity reference does not need to be used in the XML and a space is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The earth:9-12:Weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere. Solar radiation heats the land masses, oceans, and air. Transfer of heat energy at the boundaries between the atmosphere, the land masses, and the oceans results in layers of different temperatures and densities in both the ocean and atmosphere. The action of gravitational force on regions of different densities causes them to rise or fall and such circulation, influenced by the rotation of the earth, produces winds and ocean currents."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:K-2:Chunks of rocks come in many sizes and shapes, from boulders to grains of sand and even smaller."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:K-2:Change is something that happens to many things."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:K-2:Animals and plants sometimes cause changes in their surroundings."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:3-5:Waves, wind, water, and ice shape and reshape the earth's land surface by eroding rock and soil in some areas and depositing them in other areas, sometimes in seasonal layers."/>
			<!--In the next benchmark, the phrase 'remains and' originally had an m-dash between remains and and. The m-dash was changed to a space because then an entity reference does not need to be used in the XML and a space is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:3-5:Rock is composed of different combinations of minerals. Smaller rocks come from the breakage and weathering of bedrock and larger rocks. Soil is made partly from weathered rock, partly from plant remains and also contains many living organisms."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:The interior of the earth is hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:Sediments of sand and smaller particles (sometimes containing the remains of organisms) are gradually buried and are cemented together by dissolved minerals to form solid rock again."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:Sedimentary rock buried deep enough may be reformed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:Thousands of layers of sedimentary rock confirm the long history of the changing surface of the earth and the changing life forms whose remains are found in successive layers. The youngest layers are not always found on top, because of folding, breaking, and uplift of layers."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:6-8:Human activities, such as reducing the amount of forest cover, increasing the amount and variety of chemicals released into the atmosphere, and intensive farming, have changed the earth's land, oceans, and atmosphere. Some of these changes have decreased the capacity of the environment to support some life forms."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:9-12:Plants alter the earth's atmosphere by removing carbon dioxide from it, using the carbon to make sugars and releasing oxygen. This process is responsible for the oxygen content of the air."/>
			<!--In the next benchmark, the phrase 'rock cycle' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:9-12:The formation, weathering, sedimentation, and reformation of rock constitute a continuing 'rock cycle' in which the total amount of material stays the same as its forms change."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:9-12:The slow movement of material within the earth results from heat flowing out from the deep interior and the action of gravitational forces on regions of different density."/>
			<!--In the next benchmark, the phrases 'earth, including' and 'basins, consists' originally had an m-dash between the resources and such and trees and can. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:9-12:The solid crust of the earth, including both the continents and the ocean basins, consists of separate plates that ride on a denser, hot, gradually deformable layer of the earth. The crust sections move very slowly, pressing against one another in some places, pulling apart in other places. Ocean-floor plates may slide under continental plates, sinking deep into the earth. The surface layers of these plates may fold, forming mountain ranges."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Processes that shape the earth:9-12:Earthquakes often occur along the boundaries between colliding plates, and molten rock from below creates pressure that is released by volcanic eruptions, helping to build up mountains. Under the ocean basins, molten rock may well up between separating plates to create new ocean floor. Volcanic activity along the ocean floor may form undersea mountains, which can thrust above the ocean's surface to become islands."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:K-2:Objects can be described in terms of the materials they are made of (clay, cloth, paper, etc.) and their physical properties (color, size, shape, weight, texture, flexibility, etc.)."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:K-2:Things can be done to materials to change some of their properties, but not all materials respond the same way to what is done to them."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:3-5:Heating and cooling cause changes in the properties of materials. Many kinds of changes occur faster under hotter conditions."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:3-5:No matter how parts of an object are assembled, the weight of the whole object made is always the same as the sum of the parts; and when a thing is broken into parts, the parts have the same total weight as the original thing."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:3-5:Materials may be composed of parts that are too small to be seen without magnification."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:3-5:When a new material is made by combining two or more materials, it has properties that are different from the original materials. For that reason, a lot of different materials can be made from a small number of basic kinds of materials."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:All matter is made up of atoms, which are far too small to see directly through a microscope. The atoms of any element are alike but are different from atoms of other elements. Atoms may stick together in well-defined molecules or may be packed together in large arrays. Different arrangements of atoms into groups compose all substances."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:Equal volumes of different substances usually have different weights."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:Atoms and molecules are perpetually in motion. Increased temperature means greater average energy, so most substances expand when heated. In solids, the atoms are closely locked in position and can only vibrate. In liquids, the atoms or molecules have higher energy, are more loosely connected, and can slide past one another; some molecules may get enough energy to escape into a gas. In gases, the atoms or molecules have still more energy and are free of one another except during occasional collisions."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:The temperature and acidity of a solution influence reaction rates. Many substances dissolve in water, which may greatly facilitate reactions between them."/>
			<!--In the next benchmark, the phrase 'elements' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:Scientific ideas about elements were borrowed from some Greek philosophers of 2,000 years earlier, who believed that everything was made from four basic substances: air, earth, fire, and water. It was the combinations of these 'elements' in different proportions that gave other substances their observable properties. The Greeks were wrong about those four, but now over 100 different elements have been identified, some rare and some plentiful, out of which everything is made. Because most elements tend to combine with others, few elements are found in their pure form."/>
			<!--In the next benchmark, the phrase 'else, as' originally had an m-dash between else and as. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:There are groups of elements that have similar properties, including highly reactive metals, less-reactive metals, highly reactive nonmetals (such as chlorine, fluorine, and oxygen), and some almost completely nonreactive gases (such as helium and neon). An especially important kind of reaction between substances involves combination of oxygen with something else, as in burning or rusting. Some elements don't fit into any of the categories; among them are carbon and hydrogen, essential elements of living matter."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:6-8:No matter how substances within a closed system interact with one another, or how they combine or break apart, the total weight of the system remains the same. The idea of atoms explains the conservation of matter: If the number of atoms stays the same no matter how they are rearranged, then their total mass stays the same."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:Atoms are made of a positive nucleus surrounded by negative electrons. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:The nucleus, a tiny fraction of the volume of an atom, is composed of protons and neutrons, each almost two thousand times heavier than an electron. The number of positive protons in the nucleus determines what an atom's electron configuration can be and so defines the element. In a neutral atom, the number of electrons equals the number of protons. But an atom may acquire an unbalanced charge by gaining or losing electrons."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:Neutrons have a mass that is nearly identical to that of protons, but neutrons have no electric charge. Although neutrons have little effect on how an atom interacts with others, they do affect the mass and stability of the nucleus. Isotopes of the same element have the same number of protons (and therefore of electrons) but differ in the number of neutrons."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:The nucleus of radioactive isotopes is unstable and spontaneously decays, emitting particles and/or wavelike radiation. It cannot be predicted exactly when, if ever, an unstable nucleus will decay, but a large group of identical nuclei decay at a predictable rate. This predictability of decay rate allows radioactivity to be used for estimating the age of materials that contain radioactive substances."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:Scientists continue to investigate atoms and have discovered even smaller constituents of which neutrons and protons are made."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:When elements are listed in order by the masses of their atoms, the same sequence of properties appears over and over again in the list."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:Atoms often join with one another in various combinations in distinct molecules or in repeating three-dimensional crystal patterns. An enormous variety of biological, chemical, and physical phenomena can be explained by changes in the arrangement and motion of atoms and molecules."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:The configuration of atoms in a molecule determines the molecule's properties. Shapes are particularly important in how large molecules interact with others."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:The structure of matter:9-12:The rate of reactions among atoms and molecules depends on how often they encounter one another, which is affected by the concentration, pressure, and temperature of the reacting materials. Some atoms and molecules are highly effective in encouraging the interaction of others."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:K-2:The sun warms the land, air, and water."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:3-5:Things that give off light often also give off heat. Heat is produced by mechanical and electrical machines, and any time one thing rubs against something else."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:3-5:When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature. A warmer object can warm a cooler one by contact or at a distance."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:3-5:Some materials conduct heat much better than others. Poor conductors can reduce heat loss."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:6-8:Energy cannot be created or destroyed, but only changed from one form into another."/>
			<!--In the next benchmark, the phrases 'universe, from' and 'people, involves' originally had an m-dash between universe adn from and people and involves. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:6-8:Most of what goes on in the universe, from exploding stars and biological growth to the operation of machines and the motion of people, involves some form of energy being transformed into another. Energy in the form of heat is almost always one of the products of an energy transformation."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:6-8:Heat can be transferred through materials by the collisions of atoms or across space by radiation. If the material is fluid, currents will be set up in it that aid the transfer of heat."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:6-8:Energy appears in different forms. Heat energy is in the disorderly motion of molecules; chemical energy is in the arrangement of atoms; mechanical energy is in moving bodies or in elastically distorted shapes; gravitational energy is in the separation of mutually attracting masses."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:9-12:Whenever the amount of energy in one place or form diminishes, the amount in other places or forms increases by the same amount."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:9-12:Heat energy in a material consists of the disordered motions of its atoms or molecules. In any interactions of atoms or molecules, the statistical odds are that they will end up with less order than they began, that is, with the heat energy spread out more evenly. With huge numbers of atoms and molecules, the greater disorder is almost certain."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:9-12:Transformations of energy usually produce some energy in the form of heat, which spreads around by radiation or conduction into cooler places. Although just as much total energy remains, its being spread out more evenly means less can be done with it."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:9-12:Different energy levels are associated with different configurations of atoms and molecules. Some changes of configuration require an input of energy whereas others release energy."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:9-12:When energy of an isolated atom or molecule changes, it does so in a definite jump from one value to another, with no possible values in between. The change in energy occurs when radiation is absorbed or emitted, so the radiation also has distinct energy values. As a result, the light emitted or absorbed by separate atoms or molecules (as in a gas) can be used to identify what the substance is."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Energy transformations:9-12:Energy is released whenever the nuclei of very heavy atoms, such as uranium or plutonium, split into middleweight ones, or when very light nuclei, such as those of hydrogen and helium, combine into heavier ones. The energy released in each nuclear reaction is very much greater than the energy given off in each chemical reaction."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:K-2:Things move in many different ways, such as straight, zigzag, round and round, back and forth, and fast and slow."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:K-2:The way to change how something is moving is to give it a push or a pull."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:K-2:Things that make sound vibrate."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:3-5:Changes in speed or direction of motion are caused by forces. The greater the force is, the greater the change in motion will be. The more massive an object is, the less effect a given force will have."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:3-5:How fast things move differs greatly. Some things are so slow that their journey takes a long time; others move too fast for people to even see them."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:6-8:Light from the sun is made up of a mixture of many different colors of light, even though to the eye the light looks almost white. Other things that give off or reflect light have a different mix of colors."/>
			<!--In the next benchmark, the phrase 'seen' and 'heard' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<!--In the next benchmark, the phrase 'eye, just' originally had an m-dash between eye and just. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:6-8:Something can be 'seen' when light waves emitted or reflected by it enter the eye, just as something can be 'heard' when sound waves from it enter the ear."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:6-8:An unbalanced force acting on an object changes its speed or direction of motion, or both.  If the force acts toward a single center, the object's path may curve into an orbit around the center."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:6-8:Vibrations in materials set up wavelike disturbances that spread away from the source. Sound and earthquake waves are examples. These and other waves move at different speeds in different materials."/>
			<!--In the next benchmark, the phrase 'radiation, visible' originally had an m-dash between radiation and visible. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:6-8:Human eyes respond to only a narrow range of wavelengths of electromagnetic radiation, visible light. Differences of wavelength within that range are perceived as differences in color."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:9-12:The change in motion of an object is proportional to the applied force and inversely proportional to the mass."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:9-12:All motion is relative to whatever frame of reference is chosen, for there is no motionless frame from which to judge all motion."/>
			<!--In the next benchmark, the phrase 'speed of light' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<!--In the next benchmark, the phrase 'speed, the' originally had an m-dash between speed and the. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:9-12:Accelerating electric charges produce electromagnetic waves around them. A great variety of radiations are electromagnetic waves: radio waves, microwaves, radiant heat, visible light, ultraviolet radiation, x rays, and gamma rays. These wavelengths vary from radio waves, the longest, to gamma rays, the shortest. In empty space, all electromagnetic waves move at the same speed, the 'speed of light'."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:9-12:Whenever one thing exerts a force on another, an equal amount of force is exerted back on it."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:9-12:The observed wavelength of a wave depends upon the relative motion of the source and the observer. If either is moving toward the other, the observed wavelength is shorter; if either is moving away, the wavelength is longer. Because the light seen from almost all distant galaxies has longer wavelengths than comparable light here on earth, astronomers believe that the whole universe is expanding."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Motion:9-12:Waves can superpose on one another, bend around corners, reflect off surfaces, be absorbed by materials they enter, and change direction when entering a new material. All these effects vary with wavelength. The energy of waves (like any form of energy) can be changed into other forms of energy."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:K-2:Things near the earth fall to the ground unless something holds them up."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:K-2:Magnets can be used to make some things move without being touched."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:3-5:The earth's gravity pulls any object toward it without touching it."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:3-5:Without touching them, a magnet pulls on all things made of iron and either pushes or pulls on other magnets."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:3-5:Without touching them, material that has been electrically charged pulls on all other materials and may either push or pull other charged materials."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:6-8:Every object exerts gravitational force on every other object. The force depends on how much mass the objects have and on how far apart they are. The force is hard to detect unless at least one of the objects has a lot of mass."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:6-8:The sun's gravitational pull holds the earth and other planets in their orbits, just as the planets' gravitational pull keeps their moons in orbit around them."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:6-8:Electric currents and magnets can exert a force on each other."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:9-12:Gravitational force is an attraction between masses. The strength of the force is proportional to the masses and weakens rapidly with increasing distance between them."/>
			<!--In the next benchmark, the phrase 'contact, as' originally had an m-dash between contact and as. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:9-12:Electromagnetic forces acting within and between atoms are vastly stronger than the gravitational forces acting between the atoms. At the atomic level, electric forces between oppositely charged electrons and protons hold atoms and molecules together and thus are involved in all chemical reactions. On a larger scale, these forces hold solid and liquid materials together and act between objects when they are in contact, as in sticking or sliding friction."/>
			<!--In the next benchmark, the phrase 'charges, positive' originally had an m-dash between charges and positive. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:9-12:There are two kinds of charges, positive and negative. Like charges repel one another, opposite charges attract. In materials, there are almost exactly equal proportions of positive and negative charges, making the materials as a whole electrically neutral. Negative charges, being associated with electrons, are far more mobile in materials than positive charges are. A very small excess or deficit of negative charges in a material produces noticeable electric forces."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:9-12:Different kinds of materials respond differently to electric forces. In conducting materials such as metals, electric charges flow easily, whereas in insulating materials such as glass, they can move hardly at all. At very low temperatures, some materials become superconductors and offer no resistance to the flow of current. In between these extremes, semiconducting materials differ greatly in how well they conduct, depending on their exact composition."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:9-12:Magnetic forces are very closely related to electric forces and can be thought of as different aspects of a single electromagnetic force. Moving electric charges produce magnetic forces and moving magnets produce electric forces. The interplay of electric and magnetic forces is the basis for electric motors, generators, and many other modern technologies, including the production of electromagnetic waves."/>
			<xsd:enumeration value="AAASbenchmarks:Physical setting:Forces of nature:9-12:The forces that hold the nucleus of an atom together are much stronger than the electromagnetic force. That is why such great amounts of energy are released from the nuclear reactions in the sun and other stars."/>
		</xsd:restriction>
	</xsd:simpleType>
	<xsd:simpleType name="AAAScontentPhysicalLeafType">
		<xsd:annotation>
			<xsd:documentation>
				***************************************  AAAScontentPhysicalLeafType  ***************************************
				Lists leaf values
			</xsd:documentation>
		</xsd:annotation>
		<xsd:restriction base="xsd:string">
			<xsd:enumeration value="There are more stars in the sky than anyone can easily count, but they are not scattered evenly, and they are not all the same in brightness or color."/>
			<xsd:enumeration value="The sun can be seen only in the daytime, but the moon can be seen sometimes at night and sometimes during the day. The sun, moon, and stars all appear to move slowly across the sky."/>
			<xsd:enumeration value="The moon looks a little different every day, but looks the same again about every four weeks."/>
			<xsd:enumeration value="The patterns of stars in the sky stay the same, although they appear to move across the sky nightly, and different stars can be seen in different seasons."/>
			<xsd:enumeration value="Telescopes magnify the appearance of some distant objects in the sky, including the moon and the planets. The number of stars that can be seen through telescopes is dramatically greater than can be seen by the unaided eye."/>
			<xsd:enumeration value="Planets change their positions against the background of stars."/>
			<xsd:enumeration value="The earth is one of several planets that orbit the sun, and the moon orbits around the earth."/>
			<xsd:enumeration value="Stars are like the sun, some being smaller and some larger, but so far away that they look like points of light."/>
			<xsd:enumeration value="The sun is a medium-sized star located near the edge of a disk-shaped galaxy of stars, part of which can be seen as a glowing band of light that spans the sky on a very clear night. The universe contains many billions of galaxies, and each galaxy contains many billions of stars. To the naked eye, even the closest of these galaxies is no more than a dim, fuzzy spot."/>
			<xsd:enumeration value="The sun is many thousands of times closer to the earth than any other star. Light from the sun takes a few minutes to reach the earth, but light from the next nearest star takes a few years to arrive. The trip to that star would take the fastest rocket thousands of years. Some distant galaxies are so far away that their light takes several billion years to reach the earth. People on earth, therefore, see them as they were that long ago in the past."/>
			<xsd:enumeration value="Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits.  Some planets have a great variety of moons and even flat rings of rock and ice particles orbiting around them.  Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris."/>
			<!--In the next benchmark, the phrase 'atmosphere and' originally had an m-dash between the words atmosphere and and. The m-dash was changed to a space because then an entity reference does not need to be used in the XML and a space is grammatically fine.-->
			<xsd:enumeration value="Large numbers of chunks of rock orbit the sun. Some of those that the earth meets in its yearly orbit around the sun glow and disintegrate from friction as they plunge through the atmosphere and sometimes impact the ground.  Other chunks of rocks mixed with ice have long, off-center orbits that carry them close to the sun, where the sun's radiation (of light and particles) boils off frozen material from their surfaces and pushes it into a long, illuminated tail."/>
			<xsd:enumeration value="The stars differ from each other in size, temperature, and age, but they appear to be made up of the same elements that are found on the earth and to behave according to the same physical principles. Unlike the sun, most stars are in systems of two or more stars orbiting around one another."/>
			<xsd:enumeration value="On the basis of scientific evidence, the universe is estimated to be over ten billion years old. The current theory is that its entire contents expanded explosively from a hot, dense, chaotic mass. Stars condensed by gravity out of clouds of molecules of the lightest elements until nuclear fusion of the light elements into heavier ones began to occur. Fusion released great amounts of energy over millions of years.  Eventually, some stars exploded, producing clouds of heavy elements from which other stars and planets could later condense. The process of star formation and destruction continues."/>
			<xsd:enumeration value="Increasingly sophisticated technology is used to learn about the universe. Visual, radio, and x-ray telescopes collect information from across the entire spectrum of electromagnetic waves; computers handle an avalanche of data and increasingly complicated computations to interpret them; space probes send back data and materials from the remote parts of the solar system; and accelerators give subatomic particles energies that simulate conditions in the stars and in the early history of the universe before stars formed."/>
			<xsd:enumeration value="Mathematical models and computer simulations are used in studying evidence from many sources in order to form a scientific account of the universe."/>
			<xsd:enumeration value="Some events in nature have a repeating pattern. The weather changes some from day to day, but things such as temperature and rain (or snow) tend to be high, low, or medium in the same months every year."/>
			<xsd:enumeration value="Water can be a liquid or a solid and can go back and forth from one form to the other. If water is turned into ice and then the ice is allowed to melt, the amount of water is the same as it was before freezing."/>
			<xsd:enumeration value="Water left in an open container disappears, but water in a closed container does not disappear."/>
			<xsd:enumeration value="Things on or near the earth are pulled toward it by the earth's gravity."/>
			<xsd:enumeration value="Like all planets and stars, the earth is approximately spherical in shape. The rotation of the earth on its axis every 24 hours produces the night-and-day cycle. To people on earth, this turning of the planet makes it seem as though the sun, moon, planets, and stars are orbiting the earth once a day."/>
			<xsd:enumeration value="When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water."/>
			<xsd:enumeration value="Air is a substance that surrounds us, takes up space, and whose movement we feel as wind."/>
			<xsd:enumeration value="We live on a relatively small planet, the third from the sun in the only system of planets definitely known to exist (although other, similar systems may be discovered in the universe)."/>
			<xsd:enumeration value="The earth is mostly rock. Three-fourths of its surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin blanket of air. It is the only body in the solar system that appears able to support life. The other planets have compositions and conditions very different from the earth's."/>
			<xsd:enumeration value="Everything on or anywhere near the earth is pulled toward the earth's center by gravitational force."/>
			<xsd:enumeration value="Because the earth turns daily on an axis that is tilted relative to the plane of the earth's yearly orbit around the sun, sunlight falls more intensely on different parts of the earth during the year. The difference in heating of the earth's surface produces the planet's seasons and weather patterns."/>
			<!--In the next benchmark, the phrase 'earth, the' originally had an m-dash between the words earth and the. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="The moon's orbit around the earth once in about 28 days changes what part of the moon is lighted by the sun and how much of that part can be seen from the earth, the phases of the moon."/>
			<xsd:enumeration value="Climates have sometimes changed abruptly in the past as a result of changes in the earth's crust, such as volcanic eruptions or impacts of huge rocks from space. Even relatively small changes in atmospheric or ocean content can have widespread effects on climate if the change lasts long enough."/>
			<xsd:enumeration value="The cycling of water in and out of the atmosphere plays an important role in determining climatic patterns. Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow, and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the ocean."/>
			<xsd:enumeration value="Fresh water, limited in supply, is essential for life and also for most industrial processes. Rivers, lakes, and groundwater can be depleted or polluted, becoming unavailable or unsuitable for life."/>
			<xsd:enumeration value="Heat energy carried by ocean currents has a strong influence on climate around the world."/>
			<!--In the next benchmark, the phrases 'but, for' and 'purposes, the' originally had an m-dash between the but and for and purposes and the. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="Some minerals are very rare and some exist in great quantities, but, for practical purposes, the ability to recover them is just as important as their abundance. As minerals are depleted, obtaining them becomes more difficult. Recycling and the development of substitutes can reduce the rate of depletion but may also be costly."/>
			<!--In the next benchmark, the phrases 'resources, such' and 'trees, can' originally had an m-dash between the resources and such and trees and can. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="The benefits of the earth's resources, such as fresh water, air, soil, and trees, can be reduced by using them wastefully or by deliberately or inadvertently destroying them. The atmosphere and the oceans have a limited capacity to absorb wastes and recycle materials naturally. Cleaning up polluted air, water, or soil or restoring depleted soil, forests, or fishing grounds can be very difficult and costly."/>
			<xsd:enumeration value="Life is adapted to conditions on the earth, including the force of gravity that enables the planet to retain an adequate atmosphere, and an intensity of radiation from the sun that allows water to cycle between liquid and vapor."/>
			<!--In the next benchmark, the phrase 'fall and' originally had an m-dash between fall and and. The m-dash was changed to a space because then an entity reference does not need to be used in the XML and a space is grammatically fine.-->
			<xsd:enumeration value="Weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere. Solar radiation heats the land masses, oceans, and air. Transfer of heat energy at the boundaries between the atmosphere, the land masses, and the oceans results in layers of different temperatures and densities in both the ocean and atmosphere. The action of gravitational force on regions of different densities causes them to rise or fall and such circulation, influenced by the rotation of the earth, produces winds and ocean currents."/>
			<xsd:enumeration value="Chunks of rocks come in many sizes and shapes, from boulders to grains of sand and even smaller."/>
			<xsd:enumeration value="Change is something that happens to many things."/>
			<xsd:enumeration value="Animals and plants sometimes cause changes in their surroundings."/>
			<xsd:enumeration value="Waves, wind, water, and ice shape and reshape the earth's land surface by eroding rock and soil in some areas and depositing them in other areas, sometimes in seasonal layers."/>
			<!--In the next benchmark, the phrase 'remains and' originally had an m-dash between remains and and. The m-dash was changed to a space because then an entity reference does not need to be used in the XML and a space is grammatically fine.-->
			<xsd:enumeration value="Rock is composed of different combinations of minerals. Smaller rocks come from the breakage and weathering of bedrock and larger rocks. Soil is made partly from weathered rock, partly from plant remains and also contains many living organisms."/>
			<xsd:enumeration value="The interior of the earth is hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere."/>
			<xsd:enumeration value="Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges."/>
			<xsd:enumeration value="Sediments of sand and smaller particles (sometimes containing the remains of organisms) are gradually buried and are cemented together by dissolved minerals to form solid rock again."/>
			<xsd:enumeration value="Sedimentary rock buried deep enough may be reformed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it."/>
			<xsd:enumeration value="Thousands of layers of sedimentary rock confirm the long history of the changing surface of the earth and the changing life forms whose remains are found in successive layers. The youngest layers are not always found on top, because of folding, breaking, and uplift of layers."/>
			<xsd:enumeration value="Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms."/>
			<xsd:enumeration value="Human activities, such as reducing the amount of forest cover, increasing the amount and variety of chemicals released into the atmosphere, and intensive farming, have changed the earth's land, oceans, and atmosphere. Some of these changes have decreased the capacity of the environment to support some life forms."/>
			<xsd:enumeration value="Plants alter the earth's atmosphere by removing carbon dioxide from it, using the carbon to make sugars and releasing oxygen. This process is responsible for the oxygen content of the air."/>
			<!--In the next benchmark, the phrase 'rock cycle' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<xsd:enumeration value="The formation, weathering, sedimentation, and reformation of rock constitute a continuing 'rock cycle' in which the total amount of material stays the same as its forms change."/>
			<xsd:enumeration value="The slow movement of material within the earth results from heat flowing out from the deep interior and the action of gravitational forces on regions of different density."/>
			<!--In the next benchmark, the phrases 'earth, including' and 'basins, consists' originally had an m-dash between the resources and such and trees and can. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="The solid crust of the earth, including both the continents and the ocean basins, consists of separate plates that ride on a denser, hot, gradually deformable layer of the earth. The crust sections move very slowly, pressing against one another in some places, pulling apart in other places. Ocean-floor plates may slide under continental plates, sinking deep into the earth. The surface layers of these plates may fold, forming mountain ranges."/>
			<xsd:enumeration value="Earthquakes often occur along the boundaries between colliding plates, and molten rock from below creates pressure that is released by volcanic eruptions, helping to build up mountains. Under the ocean basins, molten rock may well up between separating plates to create new ocean floor. Volcanic activity along the ocean floor may form undersea mountains, which can thrust above the ocean's surface to become islands."/>
			<xsd:enumeration value="Objects can be described in terms of the materials they are made of (clay, cloth, paper, etc.) and their physical properties (color, size, shape, weight, texture, flexibility, etc.)."/>
			<xsd:enumeration value="Things can be done to materials to change some of their properties, but not all materials respond the same way to what is done to them."/>
			<xsd:enumeration value="Heating and cooling cause changes in the properties of materials. Many kinds of changes occur faster under hotter conditions."/>
			<xsd:enumeration value="No matter how parts of an object are assembled, the weight of the whole object made is always the same as the sum of the parts; and when a thing is broken into parts, the parts have the same total weight as the original thing."/>
			<xsd:enumeration value="Materials may be composed of parts that are too small to be seen without magnification."/>
			<xsd:enumeration value="When a new material is made by combining two or more materials, it has properties that are different from the original materials. For that reason, a lot of different materials can be made from a small number of basic kinds of materials."/>
			<xsd:enumeration value="All matter is made up of atoms, which are far too small to see directly through a microscope. The atoms of any element are alike but are different from atoms of other elements. Atoms may stick together in well-defined molecules or may be packed together in large arrays. Different arrangements of atoms into groups compose all substances."/>
			<xsd:enumeration value="Equal volumes of different substances usually have different weights."/>
			<xsd:enumeration value="Atoms and molecules are perpetually in motion. Increased temperature means greater average energy, so most substances expand when heated. In solids, the atoms are closely locked in position and can only vibrate. In liquids, the atoms or molecules have higher energy, are more loosely connected, and can slide past one another; some molecules may get enough energy to escape into a gas. In gases, the atoms or molecules have still more energy and are free of one another except during occasional collisions."/>
			<xsd:enumeration value="The temperature and acidity of a solution influence reaction rates. Many substances dissolve in water, which may greatly facilitate reactions between them."/>
			<!--In the next benchmark, the phrase 'elements' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<xsd:enumeration value="Scientific ideas about elements were borrowed from some Greek philosophers of 2,000 years earlier, who believed that everything was made from four basic substances: air, earth, fire, and water. It was the combinations of these 'elements' in different proportions that gave other substances their observable properties. The Greeks were wrong about those four, but now over 100 different elements have been identified, some rare and some plentiful, out of which everything is made. Because most elements tend to combine with others, few elements are found in their pure form."/>
			<!--In the next benchmark, the phrase 'else, as' originally had an m-dash between else and as. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="There are groups of elements that have similar properties, including highly reactive metals, less-reactive metals, highly reactive nonmetals (such as chlorine, fluorine, and oxygen), and some almost completely nonreactive gases (such as helium and neon). An especially important kind of reaction between substances involves combination of oxygen with something else, as in burning or rusting. Some elements don't fit into any of the categories; among them are carbon and hydrogen, essential elements of living matter."/>
			<xsd:enumeration value="No matter how substances within a closed system interact with one another, or how they combine or break apart, the total weight of the system remains the same. The idea of atoms explains the conservation of matter: If the number of atoms stays the same no matter how they are rearranged, then their total mass stays the same."/>
			<xsd:enumeration value="Atoms are made of a positive nucleus surrounded by negative electrons. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons."/>
			<xsd:enumeration value="The nucleus, a tiny fraction of the volume of an atom, is composed of protons and neutrons, each almost two thousand times heavier than an electron. The number of positive protons in the nucleus determines what an atom's electron configuration can be and so defines the element. In a neutral atom, the number of electrons equals the number of protons. But an atom may acquire an unbalanced charge by gaining or losing electrons."/>
			<xsd:enumeration value="Neutrons have a mass that is nearly identical to that of protons, but neutrons have no electric charge. Although neutrons have little effect on how an atom interacts with others, they do affect the mass and stability of the nucleus. Isotopes of the same element have the same number of protons (and therefore of electrons) but differ in the number of neutrons."/>
			<xsd:enumeration value="The nucleus of radioactive isotopes is unstable and spontaneously decays, emitting particles and/or wavelike radiation. It cannot be predicted exactly when, if ever, an unstable nucleus will decay, but a large group of identical nuclei decay at a predictable rate. This predictability of decay rate allows radioactivity to be used for estimating the age of materials that contain radioactive substances."/>
			<xsd:enumeration value="Scientists continue to investigate atoms and have discovered even smaller constituents of which neutrons and protons are made."/>
			<xsd:enumeration value="When elements are listed in order by the masses of their atoms, the same sequence of properties appears over and over again in the list."/>
			<xsd:enumeration value="Atoms often join with one another in various combinations in distinct molecules or in repeating three-dimensional crystal patterns. An enormous variety of biological, chemical, and physical phenomena can be explained by changes in the arrangement and motion of atoms and molecules."/>
			<xsd:enumeration value="The configuration of atoms in a molecule determines the molecule's properties. Shapes are particularly important in how large molecules interact with others."/>
			<xsd:enumeration value="The rate of reactions among atoms and molecules depends on how often they encounter one another, which is affected by the concentration, pressure, and temperature of the reacting materials. Some atoms and molecules are highly effective in encouraging the interaction of others."/>
			<xsd:enumeration value="The sun warms the land, air, and water."/>
			<xsd:enumeration value="Things that give off light often also give off heat. Heat is produced by mechanical and electrical machines, and any time one thing rubs against something else."/>
			<xsd:enumeration value="When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature. A warmer object can warm a cooler one by contact or at a distance."/>
			<xsd:enumeration value="Some materials conduct heat much better than others. Poor conductors can reduce heat loss."/>
			<xsd:enumeration value="Energy cannot be created or destroyed, but only changed from one form into another."/>
			<!--In the next benchmark, the phrases 'universe, from' and 'people, involves' originally had an m-dash between universe adn from and people and involves. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="Most of what goes on in the universe, from exploding stars and biological growth to the operation of machines and the motion of people, involves some form of energy being transformed into another. Energy in the form of heat is almost always one of the products of an energy transformation."/>
			<xsd:enumeration value="Heat can be transferred through materials by the collisions of atoms or across space by radiation. If the material is fluid, currents will be set up in it that aid the transfer of heat."/>
			<xsd:enumeration value="Energy appears in different forms. Heat energy is in the disorderly motion of molecules; chemical energy is in the arrangement of atoms; mechanical energy is in moving bodies or in elastically distorted shapes; gravitational energy is in the separation of mutually attracting masses."/>
			<xsd:enumeration value="Whenever the amount of energy in one place or form diminishes, the amount in other places or forms increases by the same amount."/>
			<xsd:enumeration value="Heat energy in a material consists of the disordered motions of its atoms or molecules. In any interactions of atoms or molecules, the statistical odds are that they will end up with less order than they began, that is, with the heat energy spread out more evenly. With huge numbers of atoms and molecules, the greater disorder is almost certain."/>
			<xsd:enumeration value="Transformations of energy usually produce some energy in the form of heat, which spreads around by radiation or conduction into cooler places. Although just as much total energy remains, its being spread out more evenly means less can be done with it."/>
			<xsd:enumeration value="Different energy levels are associated with different configurations of atoms and molecules. Some changes of configuration require an input of energy whereas others release energy."/>
			<xsd:enumeration value="When energy of an isolated atom or molecule changes, it does so in a definite jump from one value to another, with no possible values in between. The change in energy occurs when radiation is absorbed or emitted, so the radiation also has distinct energy values. As a result, the light emitted or absorbed by separate atoms or molecules (as in a gas) can be used to identify what the substance is."/>
			<xsd:enumeration value="Energy is released whenever the nuclei of very heavy atoms, such as uranium or plutonium, split into middleweight ones, or when very light nuclei, such as those of hydrogen and helium, combine into heavier ones. The energy released in each nuclear reaction is very much greater than the energy given off in each chemical reaction."/>
			<xsd:enumeration value="Things move in many different ways, such as straight, zigzag, round and round, back and forth, and fast and slow."/>
			<xsd:enumeration value="The way to change how something is moving is to give it a push or a pull."/>
			<xsd:enumeration value="Things that make sound vibrate."/>
			<xsd:enumeration value="Changes in speed or direction of motion are caused by forces. The greater the force is, the greater the change in motion will be. The more massive an object is, the less effect a given force will have."/>
			<xsd:enumeration value="How fast things move differs greatly. Some things are so slow that their journey takes a long time; others move too fast for people to even see them."/>
			<xsd:enumeration value="Light from the sun is made up of a mixture of many different colors of light, even though to the eye the light looks almost white. Other things that give off or reflect light have a different mix of colors."/>
			<!--In the next benchmark, the phrase 'seen' and 'heard' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<!--In the next benchmark, the phrase 'eye, just' originally had an m-dash between eye and just. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="Something can be 'seen' when light waves emitted or reflected by it enter the eye, just as something can be 'heard' when sound waves from it enter the ear."/>
			<xsd:enumeration value="An unbalanced force acting on an object changes its speed or direction of motion, or both.  If the force acts toward a single center, the object's path may curve into an orbit around the center."/>
			<xsd:enumeration value="Vibrations in materials set up wavelike disturbances that spread away from the source. Sound and earthquake waves are examples. These and other waves move at different speeds in different materials."/>
			<!--In the next benchmark, the phrase 'radiation, visible' originally had an m-dash between radiation and visible. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="Human eyes respond to only a narrow range of wavelengths of electromagnetic radiation, visible light. Differences of wavelength within that range are perceived as differences in color."/>
			<xsd:enumeration value="The change in motion of an object is proportional to the applied force and inversely proportional to the mass."/>
			<xsd:enumeration value="All motion is relative to whatever frame of reference is chosen, for there is no motionless frame from which to judge all motion."/>
			<!--In the next benchmark, the phrase 'speed of light' originally had double quotes surrounding it. The double quotes were replaced with single quotes because a double quote is a reserved character in XML schema.-->
			<!--In the next benchmark, the phrase 'speed, the' originally had an m-dash between speed and the. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="Accelerating electric charges produce electromagnetic waves around them. A great variety of radiations are electromagnetic waves: radio waves, microwaves, radiant heat, visible light, ultraviolet radiation, x rays, and gamma rays. These wavelengths vary from radio waves, the longest, to gamma rays, the shortest. In empty space, all electromagnetic waves move at the same speed, the 'speed of light'."/>
			<xsd:enumeration value="Whenever one thing exerts a force on another, an equal amount of force is exerted back on it."/>
			<xsd:enumeration value="The observed wavelength of a wave depends upon the relative motion of the source and the observer. If either is moving toward the other, the observed wavelength is shorter; if either is moving away, the wavelength is longer. Because the light seen from almost all distant galaxies has longer wavelengths than comparable light here on earth, astronomers believe that the whole universe is expanding."/>
			<xsd:enumeration value="Waves can superpose on one another, bend around corners, reflect off surfaces, be absorbed by materials they enter, and change direction when entering a new material. All these effects vary with wavelength. The energy of waves (like any form of energy) can be changed into other forms of energy."/>
			<xsd:enumeration value="Things near the earth fall to the ground unless something holds them up."/>
			<xsd:enumeration value="Magnets can be used to make some things move without being touched."/>
			<xsd:enumeration value="The earth's gravity pulls any object toward it without touching it."/>
			<xsd:enumeration value="Without touching them, a magnet pulls on all things made of iron and either pushes or pulls on other magnets."/>
			<xsd:enumeration value="Without touching them, material that has been electrically charged pulls on all other materials and may either push or pull other charged materials."/>
			<xsd:enumeration value="Every object exerts gravitational force on every other object. The force depends on how much mass the objects have and on how far apart they are. The force is hard to detect unless at least one of the objects has a lot of mass."/>
			<xsd:enumeration value="The sun's gravitational pull holds the earth and other planets in their orbits, just as the planets' gravitational pull keeps their moons in orbit around them."/>
			<xsd:enumeration value="Electric currents and magnets can exert a force on each other."/>
			<xsd:enumeration value="Gravitational force is an attraction between masses. The strength of the force is proportional to the masses and weakens rapidly with increasing distance between them."/>
			<!--In the next benchmark, the phrase 'contact, as' originally had an m-dash between contact and as. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="Electromagnetic forces acting within and between atoms are vastly stronger than the gravitational forces acting between the atoms. At the atomic level, electric forces between oppositely charged electrons and protons hold atoms and molecules together and thus are involved in all chemical reactions. On a larger scale, these forces hold solid and liquid materials together and act between objects when they are in contact, as in sticking or sliding friction."/>
			<!--In the next benchmark, the phrase 'charges, positive' originally had an m-dash between charges and positive. The m-dash was changed to a comma because then an entity reference does not need to be used in the XML and a comma is grammatically fine.-->
			<xsd:enumeration value="There are two kinds of charges, positive and negative. Like charges repel one another, opposite charges attract. In materials, there are almost exactly equal proportions of positive and negative charges, making the materials as a whole electrically neutral. Negative charges, being associated with electrons, are far more mobile in materials than positive charges are. A very small excess or deficit of negative charges in a material produces noticeable electric forces."/>
			<xsd:enumeration value="Different kinds of materials respond differently to electric forces. In conducting materials such as metals, electric charges flow easily, whereas in insulating materials such as glass, they can move hardly at all. At very low temperatures, some materials become superconductors and offer no resistance to the flow of current. In between these extremes, semiconducting materials differ greatly in how well they conduct, depending on their exact composition."/>
			<xsd:enumeration value="Magnetic forces are very closely related to electric forces and can be thought of as different aspects of a single electromagnetic force. Moving electric charges produce magnetic forces and moving magnets produce electric forces. The interplay of electric and magnetic forces is the basis for electric motors, generators, and many other modern technologies, including the production of electromagnetic waves."/>
			<xsd:enumeration value="The forces that hold the nucleus of an atom together are much stronger than the electromagnetic force. That is why such great amounts of energy are released from the nuclear reactions in the sun and other stars."/>
		</xsd:restriction>
	</xsd:simpleType>
</xsd:schema>

