Absolute Zero

Student Handout

Building a Bulb Thermometer

Thermometers measure temperature. The first known accurate thermometer was invented about 350 years ago. In this activity, you will be building and calibrating your own bulb thermometer.

Procedure

1. Make your thermometer. Place the straw through the hole in the drink lid and pull it down far enough so that the portion at the top of the lid extends to the height of an index card (see illustration at right).

2. Mold the clay around the bottom of the straw to seal any gaps in the lid around the straw so no air can escape from the "bulb" of your thermometer. Make sure the clay is molded tightly around the straw.

3. Set the lid and straw aside. Fill the drink jar to the very top with room-temperature water. Place four to six drops of food coloring in the water.

4. Put the lid back on the jar and make sure it is screwed on as tightly as possible.

5. Push the edge of the index card into the clay and tape it to the straw as shown.

6. Using the pipette, add more water until the height of liquid in the straw is about halfway up the index card (if you add to much water, you can use the pipette to take some out). Then add another drop of food coloring.

7. Use the "Calibrating Your Thermometer" handout to calibrate your thermometer. Then answer the questions below.

Questions
Write your answers on a separate sheet of paper.

1. What happened when you placed your thermometer in the warm water bath? The ice water bath? What caused the changes you observed?

2. What are the limitations of your thermometer?

3. What other scales could you use to represent the different temperatures you measured?

4. Which of the following temperatures would you prefer outside: 24 degrees Celsius or 70 degrees Celsius? Why?