<?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 historical perspectives.	
		</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="AAAScontentHistoricalType">
		<xsd:annotation>
			<xsd:documentation>
				***************************************  AAAScontentHistoricalType  ***************************************
				Lists the values that will appear in the metadata record
			</xsd:documentation>
		</xsd:annotation>
		<xsd:restriction base="xsd:string">
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:6-8:The motion of an object is always judged with respect to some other object or point and so the idea of absolute motion or rest is misleading."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:6-8:Telescopes reveal that there are many more stars in the night sky than are evident to the unaided eye, the surface of the moon has many craters and mountains, the sun has dark spots, and Jupiter and some other planets have their own moons."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:9-12:People perceive that the earth is large and stationary and that all other objects in the sky orbit around it. That perception was the basis for theories of how the universe is organized that prevailed for over 2,000 years."/>
			<!--In the next benchmark, the phrase 'wandering stars' 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:Historical perspectives:Displacing the earth from the center of the universe:9-12:Ptolemy, an Egyptian astronomer living in the second century A.D., devised a powerful mathematical model of the universe based on constant motion in perfect circles, and circles on circles. With the model, he was able to predict the motions of the sun, moon, and stars, and even of the irregular 'wandering stars' now called planets."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:9-12:In the 16th century, a Polish astronomer named Copernicus suggested that all those same motions could be explained by imagining that the earth was turning around once a day and orbiting around the sun once a year. This explanation was rejected by nearly everyone because it violated common sense and required the universe to be unbelievably large. Worse, it flew in the face of the belief, universally held at the time, that the earth was at the center of the universe."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:9-12:Johannes Kepler, a German astronomer who lived at about the same time as Galileo, showed mathematically that Copernicus' idea of a sun-centered system worked well if uniform circular motion was replaced with uneven (but predictable) motion along off-center ellipses."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:9-12:Using the newly invented telescope to study the sky, Galileo made many discoveries that supported the ideas of Copernicus. It was Galileo who found the moons of Jupiter, sunspots, craters and mountains on the moon, and many more stars than were visible to the unaided eye."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Displacing the earth from the center of the universe:9-12:Writing in Italian rather than in Latin (the language of scholars at the time), Galileo presented arguments for and against the two main views of the universe in a way that favored the newer view. That brought the issue to the educated people of the time and created political, religious, and scientific controversy."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Uniting the heavens and earth:9-12:Isaac Newton created a unified view of force and motion in which motion everywhere in the universe can be explained by the same few rules. His mathematical analysis of gravitational force and motion showed that planetary orbits had to be the very ellipses that Kepler had proposed two generations earlier."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Uniting the heavens and earth:9-12:Newton's system was based on the concepts of mass, force, and acceleration, his three laws of motion relating them, and a physical law stating that the force of gravity between any two objects in the universe depends only upon their masses and the distance between them."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Uniting the heavens and earth:9-12:The Newtonian model made it possible to account for such diverse phenomena as tides, the orbits of planets and moons, the motion of falling objects, and the earth's equatorial bulge."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Uniting the heavens and earth:9-12:For several centuries, Newton's science was accepted without major changes because it explained so many different phenomena, could be used to predict many physical events (such as the appearance of Halley's comet), was mathematically sound, and had many practical applications."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Uniting the heavens and earth:9-12:Although overtaken in the 20th century by Einstein's relativity theory, Newton's ideas persist and are widely used. Moreover, his influence has extended far beyond physics and astronomy, serving as a model for other sciences and even raising philosophical questions about free will and the organization of social systems."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Relating matter and energy and time and space:9-12:As a young man, Albert Einstein, a German scientist, formulated the special theory of relativity, which brought about revolutionary changes in human understanding of nature. A decade later, he proposed the general theory of relativity, which, along with Newton's work, ranks as one of the greatest human accomplishments in all of history."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Relating matter and energy and time and space:9-12:Among the surprising ideas of special relativity is that nothing can travel faster than the speed of light, which is the same for all observers no matter how they or the light source happen to be moving."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Relating matter and energy and time and space:9-12:The special theory of relativity is best known for stating that any form of energy has mass, and that matter itself is a form of energy. The famous relativity equation, E = mc2, holds that the transformation of even a tiny amount of matter will release an enormous amount of other forms of energy, in that the c in the equation stands for the immense speed of light."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Relating matter and energy and time and space:9-12:General relativity theory pictures Newton's gravitational force as a distortion of space and time."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Relating matter and energy and time and space:9-12:Many predictions from Einstein's theory of relativity have been confirmed on both atomic and astronomical scales. Still, the search continues for an even more powerful theory of the architecture of the universe."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Extending time:9-12:Scientific evidence implies that some rock near the earth's surface is several billion years old. But until the 19th century, most people believed that the earth was created just a few thousand years ago."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Extending time:9-12:The idea that the earth might be vastly older than most people believed made little headway in science until the publication of Principles of Geology by an English scientist, Charles Lyell, early in the 19th century. The impact of Lyell's book was a result of both the wealth of observations it contained on the patterns of rock layers in mountains and the locations of various kinds of fossils, and of the careful logic he used in drawing inferences from his data."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Extending time:9-12:In formulating and presenting his theory of biological evolution, Charles Darwin adopted Lyell's belief about the age of the earth and his style of buttressing his argument with vast amounts of evidence."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Moving continents:9-12:The idea of continental drift was suggested by the matching shapes of the Atlantic coasts of Africa and South America, but rejected for lack of other evidence. It just seemed absurd that anything as massive as a continent could move around."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Moving continents:9-12:Early in the 20th century, Alfred Wegener, a German scientist, reintroduced the idea of moving continents, adding such evidence as the underwater shapes of the continents, the similarity of life forms and land forms in corresponding parts of Africa and South America, and the increasing separation of Greenland and Europe. Still, very few contemporary scientists adopted his theory."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Moving continents:9-12:The theory of plate tectonics was finally accepted by the scientific community in the 1960s, when further evidence had accumulated in support of it. The theory was seen to provide an explanation for a diverse array of seemingly unrelated phenomena, and there was a scientifically sound physical explanation of how such movement could occur."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:6-8:From the earliest times until now, people have believed that even though millions of different kinds of material seem to exist in the world, most things must be made up of combinations of just a few basic kinds of things. There has not always been agreement, however, on what those basic kinds of things are. One theory long ago was that the basic substances were earth, water, air, and fire. Scientists now know that these are not the basic substances. But the old theory seemed to explain many observations about the world."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:6-8:Today, scientists are still working out the details of what the basic kinds of matter are and of how they combine, or can be made to combine, to make other substances."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:6-8:Experimental and theoretical work done by French scientist Antoine Lavoisier in the decade between the American and French revolutions led to the modern science of chemistry."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:6-8:Lavoisier's work was based on the idea that when materials react with each other many changes can take place but that in every case the total amount of matter afterward is the same as before. He successfully tested the concept of conservation of matter by conducting a series of experiments in which he carefully measured all the substances involved in burning, including the gases used and those given off."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:6-8:Alchemy was chiefly an effort to change base metals like lead into gold and to produce an elixir that would enable people to live forever. It failed to do that or to create much knowledge of how substances react with each other. The more scientific study of chemistry that began in Lavoisier's time has gone far beyond alchemy in understanding reactions and producing new materials."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:9-12:Lavoisier invented a whole new field of science based on a theory of materials, physical laws, and quantitative methods, with the conservation of matter at its core. He persuaded a generation of scientists that his approach accounted for the experimental results better than other chemical systems."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:9-12:Lavoisier's system for naming substances and describing their reactions contributed to the rapid growth of chemistry by enabling scientists everywhere to share their findings about chemical reactions with one another without ambiguity."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:9-12:John Dalton's modernization of the ancient Greek ideas of element, atom, compound, and molecule strengthened the new chemistry by providing a physical explanation for reactions that could be expressed in quantitative terms."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Understanding fire:9-12:While the basic ideas of Lavoisier and Dalton have survived, the advancement of chemistry since their time now makes possible an explanation of the bonding that takes place between atoms during chemical reactions in terms of the inner workings of atoms."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Splitting the atom:6-8:The accidental discovery that minerals containing uranium darken photographic film, as light does, led to the idea of radioactivity."/>
			<!--In the next benchmark, the phrase 'differenct fields, in physics' originally had an m-dash between the words fields and in. 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:Historical perspectives:Splitting the atom:6-8:In their laboratory in France, Marie Curie and her husband, Pierre Curie, isolated two new elements that caused most of the radioactivity of the uranium mineral. They named one radium because it gave off powerful, invisible rays, and the other polonium in honor of Madame Curie's country of birth. Marie Curie was the first scientist ever to win the Nobel prize in two different fields, in physics, shared with her husband, and later in chemistry."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Splitting the atom:9-12:The Curies made radium available to researchers all over the world, increasing the study of radioactivity and leading to the realization that one kind of atom may change into another kind, and so must be made up of smaller parts. These parts were demonstrated by other scientists to be a small, dense nucleus that contains protons and neutrons and is surrounded by a cloud of electrons."/>
			<!--In the next benchmark, changed the words 'radio active' to be 'radioactive' because it should be one word to be correct grammatically.-->
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Splitting the atom:9-12:Ernest Rutherford of New Zealand and his colleagues discovered that the heavy radioactive element uranium spontaneously splits itself into a slightly lighter nucleus and a very light helium nucleus."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Splitting the atom:9-12:Later, Austrian and German scientists showed that when uranium is struck by neutrons, it splits into two nearly equal parts plus one or two extra neutrons. Lise Meitner, an Austrian physicist, was the first to point out that if these fragments added up to less mass than the original uranium nucleus, then Einstein's special relativity theory predicted that a large amount of energy would be released. Enrico Fermi, an Italian working with colleagues in the United States, showed that the extra neutrons trigger more fissions and so create a sustained chain reaction in which a prodigious amount of energy is given off."/>
			<!--In next benchmark removed the extra space between the words conversion and nuclear.-->
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Splitting the atom:9-12:A massive effort went into developing the technology for the two nuclear fission bombs used on Japan in World War II, nuclear fusion weapons that followed, and reactors for the controlled conversion of nuclear energy into electric energy. Nuclear weapons and energy remain matters of public concern and controversy."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Splitting the atom:9-12:Radioactivity has many uses other than generating energy, including in medicine, industry, and scientific research in many different fields."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Explaining the diversity of life:9-12:The scientific problem that led to the theory of natural selection was how to explain similarities within the great diversity of existing and fossil organisms."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Explaining the diversity of life:9-12:Prior to Charles Darwin, the most widespread belief was that all known species were created at the same time and remained unchanged throughout history. Some scientists at the time believed that features an individual acquired during its lifetime could be passed on to its offspring, and the species could thereby gradually change to fit its environment better."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Explaining the diversity of life:9-12:Darwin argued that only biologically inherited characteristics could be passed on to offspring. Some of these characteristics were advantageous in surviving and reproducing. The offspring would also inherit and pass on those advantages, and over generations the aggregation of these inherited advantages would lead to a new species."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Explaining the diversity of life:9-12:The quick success of Darwin's book Origin of Species, published in the mid-1800s, came from the clear and understandable argument it made, including the comparison of natural selection to the selective breeding of animals in wide use at the time, and from the massive array of biological and fossil evidence it assembled to support the argument."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Explaining the diversity of life:9-12:After the publication of Origin of Species, biological evolution was supported by the rediscovery of the genetics experiments of an Austrian monk, Gregor Mendel, by the identification of genes and how they are sorted in reproduction, and by the discovery that the genetic code found in DNA is the same for almost all organisms."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Explaining the diversity of life:9-12:By the 20th century, most scientists had accepted Darwin's basic idea. Today that still holds true, although differences exist concerning the details of the process and how rapidly evolution of species takes place. People usually do not reject evolution for scientific reasons but because they dislike its implications, such as the relation of human beings to other animals, or because they prefer a biblical account of creation."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Discovering germs:6-8:Throughout history, people have created explanations for disease. Some have held that disease has spiritual causes, but the most persistent biological theory over the centuries was that illness resulted from an imbalance in the body fluids. The introduction of germ theory by Louis Pasteur and others in the 19th century led to the modern belief that many diseases are caused by microorganisms, bacteria, viruses, yeasts, and parasites."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Discovering germs:6-8:Pasteur wanted to find out what causes milk and wine to spoil. He demonstrated that spoilage and fermentation occur when microorganisms enter from the air, multiply rapidly, and produce waste products. After showing that spoilage could be avoided by keeping germs out or by destroying them with heat, he investigated animal diseases and showed that microorganisms were involved. Other investigators later showed that specific kinds of germs caused specific diseases."/>
			<!--In the next benchmark, the phrase 'organisms, germs' originally had an m-dash between the words organisms and germs. 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:Historical perspectives:Discovering germs:6-8:Pasteur found that infection by disease organisms, germs, caused the body to build up an immunity against subsequent infection by the same organisms. He then demonstrated that it was possible to produce vaccines that would induce the body to build immunity to a disease without actually causing the disease itself."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Discovering germs:6-8:Changes in health practices have resulted from the acceptance of the germ theory of disease. Before germ theory, illness was treated by appeals to supernatural powers or by trying to adjust body fluids through induced vomiting, bleeding, or purging. The modern approach emphasizes sanitation, the safe handling of food and water, the pasteurization of milk, quarantine, and aseptic surgical techniques to keep germs out of the body; vaccinations to strengthen the body's immune system against subsequent infection by the same kind of microorganisms; and antibiotics and other chemicals and processes to destroy microorganisms."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Discovering germs:6-8:In medicine, as in other fields of science, discoveries are sometimes made unexpectedly, even by accident. But knowledge and creative insight are usually required to recognize the meaning of the unexpected."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Harnessing power:6-8:Until the 1800s, most manufacturing was done in homes, using small, handmade machines that were powered by muscle, wind, or running water. New machinery and steam engines to drive them made it possible to replace craftsmanship with factories, using fuels as a source of energy.  In the factory system, workers, materials, and energy could be brought together efficiently."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Harnessing power:6-8:The invention of the steam engine was at the center of the Industrial Revolution. It converted the chemical energy stored in wood and coal, which were plentiful, into mechanical work. The steam engine was invented to solve the urgent problem of pumping water out of coal mines. As improved by James Watt, it was soon used to move coal, drive manufacturing machinery, and power locomotives, ships, and even the first automobiles."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Harnessing power:9-12:The Industrial Revolution happened first in Great Britain because that country made practical use of science, had access by sea to world resources and markets, and had an excess of farm workers willing to become factory workers."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Harnessing power:9-12:The Industrial Revolution increased the productivity of each worker but it also increased child labor and unhealthy working conditions, and it gradually destroyed the craft tradition. The economic imbalances of the Industrial Revolution led to a growing conflict between factory owners and workers and contributed to the main political ideologies of the 20th century."/>
			<xsd:enumeration value="AAASbenchmarks:Historical perspectives:Harnessing power:9-12:The Industrial Revolution is still underway as electric, electronic, and computer technologies change patterns of work and bring with them economic and social consequences."/>
		</xsd:restriction>
	</xsd:simpleType>
	<xsd:simpleType name="AAAScontentHistoricalLeafType">
		<xsd:annotation>
			<xsd:documentation>
				***************************************  AAAScontentHistoricalLeafType  ***************************************
				Lists leaf values
			</xsd:documentation>
		</xsd:annotation>
		<xsd:restriction base="xsd:string">
			<xsd:enumeration value="The motion of an object is always judged with respect to some other object or point and so the idea of absolute motion or rest is misleading."/>
			<xsd:enumeration value="Telescopes reveal that there are many more stars in the night sky than are evident to the unaided eye, the surface of the moon has many craters and mountains, the sun has dark spots, and Jupiter and some other planets have their own moons."/>
			<xsd:enumeration value="People perceive that the earth is large and stationary and that all other objects in the sky orbit around it. That perception was the basis for theories of how the universe is organized that prevailed for over 2,000 years."/>
			<!--In the next benchmark, the phrase 'wandering stars' 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="Ptolemy, an Egyptian astronomer living in the second century A.D., devised a powerful mathematical model of the universe based on constant motion in perfect circles, and circles on circles. With the model, he was able to predict the motions of the sun, moon, and stars, and even of the irregular 'wandering stars' now called planets."/>
			<xsd:enumeration value="In the 16th century, a Polish astronomer named Copernicus suggested that all those same motions could be explained by imagining that the earth was turning around once a day and orbiting around the sun once a year. This explanation was rejected by nearly everyone because it violated common sense and required the universe to be unbelievably large. Worse, it flew in the face of the belief, universally held at the time, that the earth was at the center of the universe."/>
			<xsd:enumeration value="Johannes Kepler, a German astronomer who lived at about the same time as Galileo, showed mathematically that Copernicus' idea of a sun-centered system worked well if uniform circular motion was replaced with uneven (but predictable) motion along off-center ellipses."/>
			<xsd:enumeration value="Using the newly invented telescope to study the sky, Galileo made many discoveries that supported the ideas of Copernicus. It was Galileo who found the moons of Jupiter, sunspots, craters and mountains on the moon, and many more stars than were visible to the unaided eye."/>
			<xsd:enumeration value="Writing in Italian rather than in Latin (the language of scholars at the time), Galileo presented arguments for and against the two main views of the universe in a way that favored the newer view. That brought the issue to the educated people of the time and created political, religious, and scientific controversy."/>
			<xsd:enumeration value="Isaac Newton created a unified view of force and motion in which motion everywhere in the universe can be explained by the same few rules. His mathematical analysis of gravitational force and motion showed that planetary orbits had to be the very ellipses that Kepler had proposed two generations earlier."/>
			<xsd:enumeration value="Newton's system was based on the concepts of mass, force, and acceleration, his three laws of motion relating them, and a physical law stating that the force of gravity between any two objects in the universe depends only upon their masses and the distance between them."/>
			<xsd:enumeration value="The Newtonian model made it possible to account for such diverse phenomena as tides, the orbits of planets and moons, the motion of falling objects, and the earth's equatorial bulge."/>
			<xsd:enumeration value="For several centuries, Newton's science was accepted without major changes because it explained so many different phenomena, could be used to predict many physical events (such as the appearance of Halley's comet), was mathematically sound, and had many practical applications."/>
			<xsd:enumeration value="Although overtaken in the 20th century by Einstein's relativity theory, Newton's ideas persist and are widely used. Moreover, his influence has extended far beyond physics and astronomy, serving as a model for other sciences and even raising philosophical questions about free will and the organization of social systems."/>
			<xsd:enumeration value="As a young man, Albert Einstein, a German scientist, formulated the special theory of relativity, which brought about revolutionary changes in human understanding of nature. A decade later, he proposed the general theory of relativity, which, along with Newton's work, ranks as one of the greatest human accomplishments in all of history."/>
			<xsd:enumeration value="Among the surprising ideas of special relativity is that nothing can travel faster than the speed of light, which is the same for all observers no matter how they or the light source happen to be moving."/>
			<xsd:enumeration value="The special theory of relativity is best known for stating that any form of energy has mass, and that matter itself is a form of energy. The famous relativity equation, E = mc2, holds that the transformation of even a tiny amount of matter will release an enormous amount of other forms of energy, in that the c in the equation stands for the immense speed of light."/>
			<xsd:enumeration value="General relativity theory pictures Newton's gravitational force as a distortion of space and time."/>
			<xsd:enumeration value="Many predictions from Einstein's theory of relativity have been confirmed on both atomic and astronomical scales. Still, the search continues for an even more powerful theory of the architecture of the universe."/>
			<xsd:enumeration value="Scientific evidence implies that some rock near the earth's surface is several billion years old. But until the 19th century, most people believed that the earth was created just a few thousand years ago."/>
			<xsd:enumeration value="The idea that the earth might be vastly older than most people believed made little headway in science until the publication of Principles of Geology by an English scientist, Charles Lyell, early in the 19th century. The impact of Lyell's book was a result of both the wealth of observations it contained on the patterns of rock layers in mountains and the locations of various kinds of fossils, and of the careful logic he used in drawing inferences from his data."/>
			<xsd:enumeration value="In formulating and presenting his theory of biological evolution, Charles Darwin adopted Lyell's belief about the age of the earth and his style of buttressing his argument with vast amounts of evidence."/>
			<xsd:enumeration value="The idea of continental drift was suggested by the matching shapes of the Atlantic coasts of Africa and South America, but rejected for lack of other evidence. It just seemed absurd that anything as massive as a continent could move around."/>
			<xsd:enumeration value="Early in the 20th century, Alfred Wegener, a German scientist, reintroduced the idea of moving continents, adding such evidence as the underwater shapes of the continents, the similarity of life forms and land forms in corresponding parts of Africa and South America, and the increasing separation of Greenland and Europe. Still, very few contemporary scientists adopted his theory."/>
			<xsd:enumeration value="The theory of plate tectonics was finally accepted by the scientific community in the 1960s, when further evidence had accumulated in support of it. The theory was seen to provide an explanation for a diverse array of seemingly unrelated phenomena, and there was a scientifically sound physical explanation of how such movement could occur."/>
			<xsd:enumeration value="From the earliest times until now, people have believed that even though millions of different kinds of material seem to exist in the world, most things must be made up of combinations of just a few basic kinds of things. There has not always been agreement, however, on what those basic kinds of things are. One theory long ago was that the basic substances were earth, water, air, and fire. Scientists now know that these are not the basic substances. But the old theory seemed to explain many observations about the world."/>
			<xsd:enumeration value="Today, scientists are still working out the details of what the basic kinds of matter are and of how they combine, or can be made to combine, to make other substances."/>
			<xsd:enumeration value="Experimental and theoretical work done by French scientist Antoine Lavoisier in the decade between the American and French revolutions led to the modern science of chemistry."/>
			<xsd:enumeration value="Lavoisier's work was based on the idea that when materials react with each other many changes can take place but that in every case the total amount of matter afterward is the same as before. He successfully tested the concept of conservation of matter by conducting a series of experiments in which he carefully measured all the substances involved in burning, including the gases used and those given off."/>
			<xsd:enumeration value="Alchemy was chiefly an effort to change base metals like lead into gold and to produce an elixir that would enable people to live forever. It failed to do that or to create much knowledge of how substances react with each other. The more scientific study of chemistry that began in Lavoisier's time has gone far beyond alchemy in understanding reactions and producing new materials."/>
			<xsd:enumeration value="Lavoisier invented a whole new field of science based on a theory of materials, physical laws, and quantitative methods, with the conservation of matter at its core. He persuaded a generation of scientists that his approach accounted for the experimental results better than other chemical systems."/>
			<xsd:enumeration value="Lavoisier's system for naming substances and describing their reactions contributed to the rapid growth of chemistry by enabling scientists everywhere to share their findings about chemical reactions with one another without ambiguity."/>
			<xsd:enumeration value="John Dalton's modernization of the ancient Greek ideas of element, atom, compound, and molecule strengthened the new chemistry by providing a physical explanation for reactions that could be expressed in quantitative terms."/>
			<xsd:enumeration value="While the basic ideas of Lavoisier and Dalton have survived, the advancement of chemistry since their time now makes possible an explanation of the bonding that takes place between atoms during chemical reactions in terms of the inner workings of atoms."/>
			<xsd:enumeration value="The accidental discovery that minerals containing uranium darken photographic film, as light does, led to the idea of radioactivity."/>
			<!--In the next benchmark, the phrase 'differenct fields, in physics' originally had an m-dash between the words fields and in. 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="In their laboratory in France, Marie Curie and her husband, Pierre Curie, isolated two new elements that caused most of the radioactivity of the uranium mineral. They named one radium because it gave off powerful, invisible rays, and the other polonium in honor of Madame Curie's country of birth. Marie Curie was the first scientist ever to win the Nobel prize in two different fields, in physics, shared with her husband, and later in chemistry."/>
			<xsd:enumeration value="The Curies made radium available to researchers all over the world, increasing the study of radioactivity and leading to the realization that one kind of atom may change into another kind, and so must be made up of smaller parts. These parts were demonstrated by other scientists to be a small, dense nucleus that contains protons and neutrons and is surrounded by a cloud of electrons."/>
			<!--In the next benchmark, changed the words 'radio active' to be 'radioactive' because it should be one word to be correct grammatically.-->
			<xsd:enumeration value="Ernest Rutherford of New Zealand and his colleagues discovered that the heavy radioactive element uranium spontaneously splits itself into a slightly lighter nucleus and a very light helium nucleus."/>
			<xsd:enumeration value="Later, Austrian and German scientists showed that when uranium is struck by neutrons, it splits into two nearly equal parts plus one or two extra neutrons. Lise Meitner, an Austrian physicist, was the first to point out that if these fragments added up to less mass than the original uranium nucleus, then Einstein's special relativity theory predicted that a large amount of energy would be released. Enrico Fermi, an Italian working with colleagues in the United States, showed that the extra neutrons trigger more fissions and so create a sustained chain reaction in which a prodigious amount of energy is given off."/>
			<!--In next benchmark removed the extra space between the words conversion and nuclear.-->
			<xsd:enumeration value="A massive effort went into developing the technology for the two nuclear fission bombs used on Japan in World War II, nuclear fusion weapons that followed, and reactors for the controlled conversion of nuclear energy into electric energy. Nuclear weapons and energy remain matters of public concern and controversy."/>
			<xsd:enumeration value="Radioactivity has many uses other than generating energy, including in medicine, industry, and scientific research in many different fields."/>
			<xsd:enumeration value="The scientific problem that led to the theory of natural selection was how to explain similarities within the great diversity of existing and fossil organisms."/>
			<xsd:enumeration value="Prior to Charles Darwin, the most widespread belief was that all known species were created at the same time and remained unchanged throughout history. Some scientists at the time believed that features an individual acquired during its lifetime could be passed on to its offspring, and the species could thereby gradually change to fit its environment better."/>
			<xsd:enumeration value="Darwin argued that only biologically inherited characteristics could be passed on to offspring. Some of these characteristics were advantageous in surviving and reproducing. The offspring would also inherit and pass on those advantages, and over generations the aggregation of these inherited advantages would lead to a new species."/>
			<xsd:enumeration value="The quick success of Darwin's book Origin of Species, published in the mid-1800s, came from the clear and understandable argument it made, including the comparison of natural selection to the selective breeding of animals in wide use at the time, and from the massive array of biological and fossil evidence it assembled to support the argument."/>
			<xsd:enumeration value="After the publication of Origin of Species, biological evolution was supported by the rediscovery of the genetics experiments of an Austrian monk, Gregor Mendel, by the identification of genes and how they are sorted in reproduction, and by the discovery that the genetic code found in DNA is the same for almost all organisms."/>
			<xsd:enumeration value="By the 20th century, most scientists had accepted Darwin's basic idea. Today that still holds true, although differences exist concerning the details of the process and how rapidly evolution of species takes place. People usually do not reject evolution for scientific reasons but because they dislike its implications, such as the relation of human beings to other animals, or because they prefer a biblical account of creation."/>
			<xsd:enumeration value="Throughout history, people have created explanations for disease. Some have held that disease has spiritual causes, but the most persistent biological theory over the centuries was that illness resulted from an imbalance in the body fluids. The introduction of germ theory by Louis Pasteur and others in the 19th century led to the modern belief that many diseases are caused by microorganisms, bacteria, viruses, yeasts, and parasites."/>
			<xsd:enumeration value="Pasteur wanted to find out what causes milk and wine to spoil. He demonstrated that spoilage and fermentation occur when microorganisms enter from the air, multiply rapidly, and produce waste products. After showing that spoilage could be avoided by keeping germs out or by destroying them with heat, he investigated animal diseases and showed that microorganisms were involved. Other investigators later showed that specific kinds of germs caused specific diseases."/>
			<!--In the next benchmark, the phrase 'organisms, germs' originally had an m-dash between the words organisms and germs. 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="Pasteur found that infection by disease organisms, germs, caused the body to build up an immunity against subsequent infection by the same organisms. He then demonstrated that it was possible to produce vaccines that would induce the body to build immunity to a disease without actually causing the disease itself."/>
			<xsd:enumeration value="Changes in health practices have resulted from the acceptance of the germ theory of disease. Before germ theory, illness was treated by appeals to supernatural powers or by trying to adjust body fluids through induced vomiting, bleeding, or purging. The modern approach emphasizes sanitation, the safe handling of food and water, the pasteurization of milk, quarantine, and aseptic surgical techniques to keep germs out of the body; vaccinations to strengthen the body's immune system against subsequent infection by the same kind of microorganisms; and antibiotics and other chemicals and processes to destroy microorganisms."/>
			<xsd:enumeration value="In medicine, as in other fields of science, discoveries are sometimes made unexpectedly, even by accident. But knowledge and creative insight are usually required to recognize the meaning of the unexpected."/>
			<xsd:enumeration value="Until the 1800s, most manufacturing was done in homes, using small, handmade machines that were powered by muscle, wind, or running water. New machinery and steam engines to drive them made it possible to replace craftsmanship with factories, using fuels as a source of energy.  In the factory system, workers, materials, and energy could be brought together efficiently."/>
			<xsd:enumeration value="The invention of the steam engine was at the center of the Industrial Revolution. It converted the chemical energy stored in wood and coal, which were plentiful, into mechanical work. The steam engine was invented to solve the urgent problem of pumping water out of coal mines. As improved by James Watt, it was soon used to move coal, drive manufacturing machinery, and power locomotives, ships, and even the first automobiles."/>
			<xsd:enumeration value="The Industrial Revolution happened first in Great Britain because that country made practical use of science, had access by sea to world resources and markets, and had an excess of farm workers willing to become factory workers."/>
			<xsd:enumeration value="The Industrial Revolution increased the productivity of each worker but it also increased child labor and unhealthy working conditions, and it gradually destroyed the craft tradition. The economic imbalances of the Industrial Revolution led to a growing conflict between factory owners and workers and contributed to the main political ideologies of the 20th century."/>
			<xsd:enumeration value="The Industrial Revolution is still underway as electric, electronic, and computer technologies change patterns of work and bring with them economic and social consequences."/>
		</xsd:restriction>
	</xsd:simpleType>
</xsd:schema>

