Thermometers are everywhere and many people don’t realize how often they use a thermometer. You may see one on a bank sign, on the oven, at the doctor’s office when you are sick or inside your vehicle. Either way, thermometers are all around you and they all measure the same thing; the temperature.

What You Need To Know

  • Thermometers are an important part of weather forecasting

  • BELOW: What you need to make your own thermometer

  • BELOW: Take Nick's 5-question quiz!

  • More Project Weather School

The temperature is a common term used in daily conversation. To put it simply, the temperature is a measure of how hot or cold something is. The temperature of an object is usually associated with some sort of scale, such as Fahrenheit (⁰F), Celsius (⁰C) or Kelvin (K). The Fahrenheit scale is the most commonly used scale in the United States.

Thermometers are used to measure the temperature and this is a very important part of weather forecasting. Many thermometers come in a glass tube that contains a liquid, usually mercury or alcohol. The liquid expands when it’s hotter and contracts when it is colder.

As the temperature changes, the liquid inside the thermometer will either rise or shrink. When the liquid inside the thermometer rises, the temperature has gone up. The temperature can be read from the scale on the side of the thermometer.

Knowing the air temperature is very important. It is an important part of weather forecasting. This is especially important during the winter months in Florida because temperatures that dip below freezing (32⁰F or 0⁰C) can damage crops. Temperature also controls what people wear year round.

Experiment: Creating a Thermometer

Purpose: Build a weather instrument that can measure the temperature

What you need:

-          A clear glass bottle

-          A straw

-          Red food coloring

-          Water

-          Measuring cup (something to pour water)

-          Rubbing alcohol

-          Modeling Clay


1.       Fill the clear glass bottle with one cup of water

2.       Pour a cup of rubbing alcohol inside the glass bottle

3.       Place a few drops of red food coloring inside the bottle

4.       Mix the solution together inside the glass bottle

5.       Insert the straw but make sure the straw doesn’t touch the bottom of the glass bottle

6.       Use the modeling clay and place it around the top of the bottle to hold the straw in place.

7.       Now you have made your thermometer! Let’s test it out!

8.       You can use a hair dryer to warm up the liquid inside the bottle or an ice pack to cool the liquid inside the bottle

9.       Observe findings

Results: A functioning thermometer that can measure whether the temperature has warmed or cooled. When it is warmer, the liquid inside the straw rises and the opposite happens when it cools.  

Conclusion: The thermometer is an easy yet important tool that can be used to detect changes in the temperature.