Answer:
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:
hope this helps
