Is It Hot in Here?

Have you ever wondered how an analog thermometer works? Did you know you can build your own thermometer at home with household materials? It may not accurately tell temperature, but it sure is fun!

What You Need

  • Water
  • A glass mason jar
  • Isopropyl Alcohol (rubbing alcohol)
  • A Clear Drinking Straw
  • Clay or Play-Doh
  • Food Coloring
  • A Hammer
  • A Nail

Homemade Thermometer

What to Do

1. Add 2.5 oz of water into the jar.

2. Mix with 2.5 oz of Isopropyl Alcohol.

3. Add 3 or 4 drops of food coloring and swish to mix.

4. Using a hammer and nail poke a hole in the top of the jar. Use parental supervision!

5. Place the clear drinking straw into the jar but do not let the straw touch the bottom.

6. Form the Play-Doh around the straw to seal any gaps or holes.

7. Move your bottle into different locations to watch the mixture rise or drop in the straw.

8. In the example picture, the glass jar was placed within a glass bowl filled with warm water. The water-alcohol mixture rose about 3 inches!

What's Going On?

Have you ever used an analog thermometer where the red liquid will rise in a chamber and show you the temperature on a scale? This at-home thermometer is a demonstration of how an analog thermometer works! The water-alcohol mixture will expand as the temperature increases. To maintain constant pressure within the jar as the mixture expands, the liquid will rise in the straw. The greater the temperature, the higher the liquid will rise.

-Jamie Garrett