Heat energy is a fundamental concept in physics that all students should be familiar with. Happily, thermal energy lends itself to some simple, observable and fascinating experiments to expose young students to the science of heat. Experiments can demonstrate heat absorption of different colors, fire-proofing, the creation of work, and the role of insulation, just to name a few.
Color and Heat
One of the simplest thermal energy experiments involves demonstrating how different colors absorb solar energy differently. First, wrap several identical drinking glasses in paper of different colors. Then fill each glass with the same amount of water. Next, leave the glasses in direct sunlight for one hour. Finally, check the temperature of each glass of water.
Thermal Energy and Work
Although we can't see it, thermal energy can do work for us. To demonstrate this, put a balloon and a 1-liter bottle in a freezer for five minutes. Next, fill a bowl with lukewarm water. Put the mouth of the balloon over the opening of the 1-liter bottle and place the bottle in the bowl of warm water. The balloon should inflate as the air inside the bottle warms up. Next, with the balloon still stretched over the mouth of the bottle, place the bottle in a bowl of ice water. The balloon should then shrink down and deflate. The work of inflating and deflating the balloon has been accomplished through thermal energy.
Demonstrate the conduction and convection of heat by filling two balloons: one with cold water and one with air. Light a match and hold it under the air-filled balloon -- it should rupture. Light another match and hold it under the water-filled balloon. It should stay intact as the water inside the balloon is carrying away heat from the surface of the balloon. This conduction and convection of heat prevents the balloon rubber from reaching a melting temperature, meaning the balloon does not burst.
Insulating an Object to Prevent Loss of Thermal Energy
Insulation can be used to keep thermal energy from either entering or leaving a substance.To determine the effectiveness of various types of insulation, start by pouring the same amount hot water into four different glass jars. Take the temperature of the water in each jar. Next, cover each jar the same, but with a different type of insulation: aluminium foil, newspaper, bubble wrap and a wool sock. Let the jars sit for 10 minutes, then take the temperature of each jar to see which type of insulation retained the most thermal energy.