This demonstration consists of a glass bottle filled with water that's been dyed dark blue. The top of the bottle is stopped with a rubber stopper, and a glass capillary tube (formerly part of a thermometer) is stuck into the stopper.
This demonstration shows the elasticity of a material usually thought of as brittle and inflexible. Demonstrates the measurable strain produced in glass as a result of force exerted by squeezing the bottle.
This demonstration can be finicky at times, you may notice that the water level will increase even as you hold it.
Only a very small change in the volume of the liquid is necessary to produce a substantial change in the height of the liquid in the capillary tube, so it's very sensitive to the environment. This effectively means that, in addition to providing an effective reading of the small changes in volume of the bottle, it's also an effective thermometer and barometer.
The bottle has an internal volume of 375ml, and the visible part of the capillary tube has a length of 7.5cm and an internal diameter of 0.3mm. (somewhere between 0.25mm and 0.5mm, this is a guess.) This means that to go between the capillary being empty and the capillary being full, there must be a reduction of the bottles volume of 5.3 microliters, or a change of 0.00141%.
If you do some math, you'll find that to achieve a similar change via expansion due to heating an increase in temperature of only 0.068ºC is required.3)
Demo room information