Fahrenheit and Celsius: What's the Difference?

Fahrenheit and Celsius: What's the Difference?
Martha Washington: Science, Medicine, Inventions and tech

Skill: Elementary School
Time Required: One to two class periods


The 18th century, during which Martha Washington lived most of her life, was a time of great scientific inquiry, invention, and discovery.  Science was becoming the best way of understanding the universe, and lots of people were busy trying to do just that.   Among the many close observers of nature (which is another way to say “scientist”) were Gabriel Fahrenheit in Germany and Anders Celsius in Sweden.  Together, they gave us the answers to the question: “So, what’s the temperature going to be today?”


Students who participate in this lesson will learn about both the Fahrenheit and Celsius temperature scales and about the men to developed them; in addition, they may conduct their own temperature observations over time.

Materials Required:

Access to the Internet; a large Celsius and a large Fahrenheit thermometer or facsimile; notebook and pencils for recording temperatures.


1.  Introduce the lesson by discussing with the students the temperature outside on the day you do this lesson.  If they know that it’s “hot,” or “cold,” do they know how hot or how cold?  How do they know that?
2.  Divide students into four groups, and, using the websites listed below, assign each group the following task:

  • Group 1 – research the Fahrenheit scale
  • Group 2 – research Gabriel Daniel Fahrenheit
  • Group 3 – research the Celsius scale
  • Group 4 – research Anders Celsius

3.  Ask students to take notes on their research so that they can share their information with the rest of the class.
4.  When the research is complete, each group should report its findings: Groups 1 and 3 should use the actual (or model) thermometers you provide to explain the two scales; Groups 2 and 4 should describe the lives of the two scientists, comparing and contrasting their lives and discoveries.
5.  As a concluding activity, have each group measure the temperature of a bowl of water with a Fahrenheit thermometer and with a Celsius thermometer; make sure the water in the four bowls is of significantly different temperatures. 

Extending the Lesson:

This lesson might be extended by installing the two kinds of thermometers outside a classroom window, and having students record the daily temperature at a certain time every day for several months, or for the whole year.

Sources & Resources:



Gabriel Daniel Fahrenheit


Anders Celsius


This lesson was developed by Averil McClelland, Kent State University.