This high school physics lesson focuses on the application of the Doppler effect to sound. Discusses what the Doppler effect is, offers examples of its occurrence, and explains what shock waves and sonic boom are.

Dr. Stephen O'Brien of the National Cancer Institute discovers a 700-year-old mutation that makes a person resistant to HIV infection. From Evolution: "Evolutionary Arms Race."

This letter, from a farmer in 1767, addresses his conceerns regarding the Townshend Duties and their effect on the colonies as a whole.

Contains plans for three lessons that teach about sound and letters using Dr. Seuss's "Mr. Brown Can MOO! Can You?" In addition to objectives and standards, this instructional plan contains links to sites used in the lessons as well as assessment and reflection activities.

Read the full text of Richard Sheridan's "The Duenna." This three-act play is accompanied by a detailed introduction on Sheridan's life, career, and popular plays.

This website is a compendium of letters written by Thomas Carlyle and his wife, Jane Welsh Carlyle, to each other and to others. You can search by date, recipient, or subject.

This is an e-text of the first published selection of the poems of Emily Dickinson (1830?1886) originally appeared in 1890, edited by Mabel Loomis Todd and Thomas Wentworth Higginson. The text contains 115 poems and can be searched by first lines. It contains such familiar poems as "Because I could not stop for Death," and "I never saw a moor," as well as many less well-known works such as "That short, potential stir," or one of her longer poems, "To know just how he suffered would be dear."

This is the full text of the 1963 Equal Pay Act which ensured equal pay for women.

This Environmental Protection Agency site offers links to many documents from the EPA concerning the Clean Air Act Amendments of 1990.

Retrieve information from multiple sources of Envirofacts' System Data for your area of interest. using zip code, city, or county information.

This EPA website has links to many science topics about which the Environmental Protection Agency has concerns.

Provides information on what to do after a flood to protect well water from contamination, the testing of private well water, and protecting private well water.

In this lesson unit, students examine how Texans altered the environment in order to construct railroads, and the impact of those changes, both positive and negative. They then complete a project where they develop a plan for a railroad or analyze completed routes, and explain the consequences of building the railroad along each route.

Describes the themes and writing style of early New England historians. Clicking on the names at the bottom of each page will take you to information about individual historians.

A survey of the Quaker writers from the Colonial period extracted from The Cambridge History of English and American Literature.

An equation for the law of universal gravitation is stated. The weight equation (W=m*g) is related to the law. An interactive Javascript form allows the user to practice determining the force of gravity and the acceleration of gravity for various locations about the earth.

This video segment adapted from NASA's Goddard Space Flight Center discusses how a drought can have negative effects locally, for example by increasing the number of forest fires, and also globally, for example by impacting air quality thousands of miles away.

This video segment adapted from NASA's Goddard Space Flight Center shows how integral satellites are to everyday life and describes the different types, including orbital and geostationary.

This video segment adapted from NOVA tells the tragic story of two Japanese seismologists who disagreed about the threat of earthquakes in the early twentieth century. Today, seismologists in California offer residents a probability of risk that an earthquake might occur.