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Question: How does a thermometer work? Answer: Thermometers contain tubes that hold colored liquid such as alcohol (mercury was used until it was discovered to be hazardous when spilled). Alcohol expands when heated and contracts when cooled. When the air's temperature rises the alcohol expands and has no where to go but up the tube. Numbers outside the glass tube are calibrated to mark the temperature so when the colored liquid rises to that line, you know the temperature.

For more information about this question, check out: thermometers.

How Things Work. Think of this site as a radio call in program that is being held on the web instead of the radio. Maintained by Louis A. Bloomfield, Professor of Physics.

About Rainbows. This site answers a wide variety of questions about rainbows.

Watch a building implode! Check out this cool site that explains how lots of things work, including roller coasters and spy planes. Learn how to pick a lock and why biting on aluminum foil can hurt.

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