Support it horizontally with two blocks of wood, with one end of the rod against a wall. A pin pushed through the straw about 3 cm from the point where the straw and rod meet and into another block will act as a pivot for the straw indicator. A reference scale drawn on cardboard may be mounted to the back of the block which supports the straw. Heat the rod, using alcohol burners or candles, and watch the free end of the straw for any movement. Ask the students to find out what they can about expansion joints used in bridge construction, sidewalk construction, and other areas.
Students are able to measure a very small change by the use of amplification.
Put it in a freezer or outside if the temperature is below freezing, so that the air inside the jar is cold. Secure the cover with an elastic or string around the neck of the jar. Observe what happens to the latex as the air in the jar warms. Account for this phenomenon. Try heating the jar by placing it in a shallow pan of hot water.