How to Make a Thermometer
A thermometer is an instrument that measures the temperature.
Depending on what country you live in, temperature is measured
either in a scale called Fahrenheit or Celsius (sometimes called
Centigrade). There are thermometers for food, humans, and the
weather. You can even make a thermometer yourself, it's simple.
Here's what you'll need: - Water (plain old tap water will do
just fine for this experiment.) - Rubbing alcohol - 1 clear
plastic bottle with a narrow neck - Food coloring in your choice
of color - See-through plastic drinking straw - Modeling clay.
Pour equal parts of the water and alcohol and a couple of drops
of food coloring into the bottle (the liquid should only fill up
about a quarter of the bottle.) and give it a shake to mix. Drop
the straw into the bottle (it should touch the bottom) and plug
the opening with the clay. That's all there is to it. Now it's
time to make sure your thermometer works. What happens when you
place it in direct sunlight and the liquid becomes warmer? If
your thermometer works properly, the colored liquid will rise up
through the straw. In fact, if the liquid were to become
extremely hot, the liquid would most likely come out the top of
the straw.
Bring your thermometer outside with you, how does the colored
water react inside the straw? Does it go up or down? Run it
under warm water and then cold, the colored water will react
accordingly. Of course this isn't an accurate measure of water
temperature, and there's no way of telling how hot or cold the
water actually is, but this should give you some idea of how a
thermometer works.
Making a thermometer is a great rainy day craft for kids. It's
easy, quick and in most cases involves items found around the
house. Why not make it your next project?