Potential energy is stored energy, and kinetic energy is the release of energy as it does work. Make a ramp by setting one end of a 3 foot long plank up on a brick in order to raise it 2 to 3 inches. Fill a 2 liter plastic soda bottle with water, another with small stones and leave a third empty. Lay each bottle on its side. One at a time, place each bottle at the top of the ramp and let it roll down the inclined plane. When each bottle comes to a stop, use a tape measure to determine how far each bottle has rolled from the ramp. From your results, make a statement about the mass of an object and its potential energy. Go one step further and demonstrate a "transfer of energy" by placing the empty bottle on its side at the bottom of the ramp and rolling the water-filled bottle down the ramp. When the water bottle hits the empty bottle, energy is transferred and causes the empty bottle to roll. Measure how far the empty bottle travels. Repeat the experiment substituting the water-filled bottle for the one with small stones, and measure the distance the empty bottle travels. Use the measurements to determine which bottle has the most mass and is capable of transferring the most energy to the empty bottle.
Light travels at about 186,000 miles per second, while sound travels only about 1,100 feet per second through the air. Find a straight section of road that is at least one mile long. Mark a spot safely on the shoulder of the road were you will stand with an unobstructed view down the road. Have someone drive a car one mile away from the mark where you are standing and park safely on the side of the road with the car facing toward you. Prove that light energy travels faster than sound energy by having the driver beep the car's horn at the same time he turns on the car's headlights. You will hear the sound lag behind the light by several seconds. Use a stop watch to determine the lag time, and record this time.
Solar energy is used to heat homes, businesses and even swimming pools. There are times, however, when heat from the sun is undesirable, such as on a hot summer day when it beats against a home or shines through a window, creating a greenhouse effect. Prove that natural objects, such as trees and grass, help lower temperatures from the sun's solar energy. Hold a thermometer 4 feet from the ground and measure the temperature as you stand on an asphalt driveway during a hot, sunny day. Stand so that your shadow falls on the thermometer, keeping it out of the sunlight. Immediately after you take the measurement, stand under the shade of a nearby tree surrounded by grass. Again, hold the thermometer 4 feet above the ground and measure the temperature to show how the tree and grass have a natural cooling effect.
Windmills are becoming a popular alternative energy source used for generating electricity. To be efficient, these windmill generators are placed high atop towering structures. This is because the wind is typically stronger as you get above the ground. Prove that the wind has a faster velocity at greater heights by tying a piece of ribbon on the rope of a tall flagpole and raising it to the top. At 2 feet from the ground, tie a similar piece of ribbon to the flag pole. As the wind blows, compare the position of the ribbons to each other, and compare how much they extend out from the flagpole, like a windsock. Use a camera to take photographs that you can use in making your science fair project display.