This document explains the predictable and periodic movements of ocean waters that are known as tides and how they are produced by the gravitational forces of the moon and sun. It describes how gravitational attraction and centrifugal force create bulges on either side of the Earth (the high tides), and how two coinciding and simultaneous low tides occur at equal distances around the earth between ... Full description.

The two activities at this site allow students to conduct hands-on experiments exploring the basic principles of why ships float, and to build simple models which show how special tools on deck, using levers and pulleys, allow researchers and crew to handle heavy equipment and sample water layers deep in the ocean. In the first activity students will conduct experiments demonstrating the effects of ... Full description.

In this activity, students learn how a rocket works by ejecting gas, which produces an equal and opposite force in the direction of the rocket's flight. They will discover that rockets do not have to "push off" of the atmosphere to get into space and that it is not necessary to keep pushing a satellite to keep it moving in orbit because there is no friction in space to cause things to slow down. Students ... Full description.

This activity demonstrates how different sizes of rock materials that make up an aquifer affect water movement. Students discover that ground water must be able to move through underground materials at rates fast enough to supply useful amounts of water to wells or springs in order for those materials to be classified as an aquifer. They also learn that for water to move in an aquifer, some of the ... Full description.

This activity relates a sailing ship's route to ocean currents. The route is taken from a true account of a whaling voyage on the ship Lucy Ann in 1847-1848. The ship sailed from Long Island, New York, to the Pacific, searching in different parts of the ocean, called "whaling grounds" where whales were known to be found at certain times of year. Since whaling vessels of that time were powered by sail, ... Full description.

This activity helps students understand why compass angles need to be corrected for regional magnetic variation. The magnetic compass, perfected slowly over years of experimentation, trial, and scientific endeavor, became the sailor's most common and most reliable direction-indicating aid, but is influenced by magnetic variabilities and the location of magnetic north. Terms introduced include compass, ... Full description.

Earth's orbit around the Sun, together with the tilt of its axis, results in periodic climate changes around the globe known as seasons. Different locations experience different types of climate changes. For example, some places have extreme seasonal changes in temperature, while others have little temperature change but may have rainy and dry seasons. This interactive feature explains why Earth experiences ... Full description.

This page from the US Environmental Protection Agency features a number of educational resources in honor of this year's Earth Day celebration. There are links to localized volunteer opportunities, a series of "green tips" or ideas for reducing one's carbon footprint, and a set of lesson plans and activities for K-12 students. Full description.

"Pieces of Science" is an online gallery of sixteen educational resources related to a collection of historical science objects. This section deals with the Apollo 8 mission to the Moon. Facts about the crew and mission accomplishments, as well as the new spacesuit designed for the mission are covered. There is an activity guide for teachers, an image gallery, and on-line activities for students. ... Full description.

This lesson plan is part of the Center for Educational Resources (CERES), a series of web-based astronomy lessons created by a team of master teachers, university faculty, and NASA researchers. The activities in this lesson are designed to give students solid experiences of observing, organizing, comparing, and describing the movement of objects they see in the sky. Students will also learn how early ... Full description.