Celsius or Fahrenheit?

Celsius or Fahrenheit? lesson plan

Why do some thermometers show two different temperatures? Create your own dual-scale thermometer.

  • 1.

    Thermometers are instruments that measure temperature using Fahrenheit (F) and/or Celsius (C) scales. The freezing point of water is 32 degrees F and 0 degrees C. Compare thermometers with both scales. Then invent your own. Here are some ideas.

  • 2.

    <STRONG>Draw a thermometer</STRONG>. Use Crayola® Erasable Colored Pencils to draw a mercury-style thermometer on posterboard. Punch holes in the top and bottom. Mark F for the Fahrenheit side and a C for the Celsius side. Write in numerals and degree lines with a Crayola Fine Line Marker.

  • 3.

    <STRONG>Decorate it.</STRONG> On construction paper, draw and color items that represent hot and cold weather such as snowflakes, penguins, or sunglasses. Cut them out with Crayola Scissors. Attach them to the poster with a Crayola Glue Stick. Design a border.

  • 4.

    <STRONG> Add the "mercury."</STRONG> Measure and cut one red and one white ribbon that are each as long as the distance between the two holes. Tape one end of each color together. Thread through the holes and tape the other end.

  • 5.

    <STRONG>What’s the temperature?</STRONG> Find out the current indoor or outside temperature. Display it on your thermometer.


  • Students compare and contrast the two measurement scales of Fahrenheit and Celsius.
  • Students calculate the temperature using both measurements.
  • Students demonstrate their understanding of these systems by creating a dual-system thermometer showing both Fahrenheit and Celsius measurement.


  • Research a third system of measurement (Kelvin). Create a chart depicting the uses of each system.
  • Draw outdoor scenes. Exchange papers with classmates and estimate the temperature.
  • Take daily temperature readings in Celsius and Fahrenheit at the same spot and at the same time. Plot a graph showing results.
  • Students with special needs may need assistance to assemble the thermometer.
  • Assessment: Exchange thermometers and ask students to verify accuracy of their markings.