Have your students boil pots of water at home or in a lab.
Make them record the results of at least three different measurements of water. The results should include how long it takes the water to boil, the rate of heat increase produced after 2 minutes, and the heat increase after 5 minutes.
Explain to the students that, as water molecules vibrate faster, they heat up and eventually further their distances from each other. Eventually, the intense vibrations cause the molecules to get so hot the water turns into a gas, or steam.
Have the students each gather two sticks or stones.
Have them rub the sticks together rapidly, but carefully. After 10 seconds, have them feel the areas where the sticks or stones were rubbed together. The vibrations produced by friction make the objects slightly warmer than they were before.
Ask the students to rub the sticks or stones together for 20 seconds and note any differences they felt while touching the objects a second time.
Explain to them that, when stuck or stranded without matches or flint, these are some of the basic materials people use to produce enough heat vibrations that a fire ignites.
Encourage the students to discover other things that produce heat when vibrated against each other. Their ideas may include rubbing a paper clip on carpet, rubbing their hands together, or even putting a pencil in the sharpener.
Fill your two bottles 1/4 to 1/2 full with ice. The measurements should be the same in both bottles. Also, use the smallest sized ice possible for the best results.
Fill the bottles nearly to the top with room-temperature water.
Call two students to the front of the classroom and give them the bottles.
Have one student vigorously shake his bottle for 30 seconds. Open both containers. One will not have noticeable changes. The shaken one, however, will have thinner or completely melted ice.
Explain to the students that the bottle-shaking caused both the water student's body to heat up. Thus; the water began to melt from vibrating inside the bottle, and the hands of the student became warmer, aiding the melting process.