PRESENT YOUR FINDINGS
Answering the following questions will help you focus on the outcomes of the experiments.
Experiment 1:
1. What happens to the water in the small tube as the water in the test tube absorbs heat?
2. Why do you think a small tube was used to observe the expansion of water?
Experiment 2:
1. Compare the circumference of the balloon before and after freezing. What is the percent increase in this
measurement?
Combined Results
Write a summary paragraph discussing this experiment and the results. Use the following questions and topics to help
guide the content of your paragraph.
1. Summarize the conclusions that you can draw from this experiment. Use the questions above to guide your ideas.
2. Summarize any difficulties or problems you had in performing the experiment that might have affected the results.
Describe how you might change the procedure to avoid these problems.
3. Describe at least two real-world issues or examples that illustrate the findings of this experiment.

Set up and procedure

Use a glass testtube

Insert a 1-hole stopper in which you insert a glass tube (use a bit of glycerine around the bottom end which makes it slip easier into the stopper)

Fill the testtube with colored water

Place rubber stopper

Make sure there are no air bubbles and that the column in the glass tube is low, as indicated

Place testtube assembly into water which you will heat (hot plate)

Observations

You will observe that the water column in the glass tube moves up as the temperature of the water in the testtube increases. With a 20 mL testtube, and a temperature change from 20 degrees C to 80 degrees C, you should get something like 15-20 cm of change in height.

What do YOU observe?

How do YOU explain your observation?

What is happening there?

Explanation

The water in the testtube expands as it is heated. There is only one direction to expand in, the glass tube. This glass tube is narrow so that a small change in volume will result in a considerable change in height; your signal is amplified.

This is the same phenomenon as in thermometers with a glass bulb on the lower end. Thermometers use a variety of liquids including alcohol (expands more than water) and mercury (is dangerous when spilled).

Explanation: