Thermometer


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Here’s a hot invention that makes for very cool science.

What You Need:
• 16-ounce plastic bottle
• warm water
• food coloring
• clear plastic straw
• modeling clay
• bowl of ice
• marker

Fill a bottle to the top with warm water. Add a few drops of food coloring to the water. Stick some clay around a straw. Put 1/3 of the straw in the bottle. Use the clay to seal the bottle closed and hold the straw in place. (Make sure the bottle is completely sealed.) How much water is in the straw? Mark the water level on the straw. Put the bottle in a bowl of ice. What happens? (It may take a few minutes before you notice any changes.)

How does your thermometer compare to the one you used to measure the melting point of chocolate?

What improvements could you make to yours?

Change one thing, like use a different size bottle or a glass bottle. Then predict what you think will happen and test it.

Send your reports to:
ZOOM
Box 350
BOSTON, MA 02134
or pbskids.org/zoom

Science Scoop
Did you know that way back in 1593, Galileo (a pretty famous scientist) invented the first thermometer?

Here’s how your thermometer works: When water is heated, it expands and takes up more space. When water is cooled, it contracts and takes up less space. Did you notice how the temperature change affects the water in your straw?

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ZOOM is a production of WGBH Boston. ZOOM, all composite ZOOM words, and all related names and indicia are trademarks or registered trademarks of WGBH Educational Foundation. Used with permission.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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