Homemade Water Thermometer Experiment

Materials:
Stove, Drill, Jar with lid, clear straw, frying pan and food coloring.

Safety Precautions: Perform only under adult supervision. Excise caution with hot water. Handle jar bottle with pot holders as the water is very hot.

Procedure:
Drill a hole in the in the top of the jar lid so that a drinking straw will fit snugly through it.
Fill the jar with water to the brim. add a few drops of food coloring.
Place lid on the jar. Insert straw through the hole in the jar lid so that it touches the bottom of the jar.
Place the jar inside a pan half-filled with water. Heat the water on the stove.

Observe the water in the straw as the water is heated.

Explanation:
As water is heated its molecules move faster, causing them to spread farther apart from one another. AS a results heated water expands, causing the water to rise in the straw. Thermometers work according to the same principle. As the liquid (Mercury or alcohol) is heated, it expands and rises. As it cools, it contracts and falls.