Materials Required:
l String, about 40 inches long
l Tape
l Flashlight
l A dark room
Procedure:
- Tape one end of the string to a flashlight.
- Go into the room you have chosen and close the door. Tape the other end of the string to the center of the door at waist height, then turn off the light. (The room must be totally dark.)
- Hold the flashlight in one hand. Step back until the string is tight, then shine the light directly on the door. A circle of light will form. Notice its size.
- Now move to the side, keeping the string tight, and shine the flashlight in the same spot. The circle of light will become larger, forming an oval shape. Can you compare this to something you know about the earth and the sun?
This Is What Happens:
As you move to the side, the light hits the door at an angle and covers a greater area. Since the same amount of light covers a larger area on an angle, that area receives less intense light. The same thing happens when the sun strikes the earth’s surface at different times during the year. In the summer, we receive the sun’s rays more directly, and they, therefore, produce more heat. In the winter, however, we receive the slanted rays of the sun, and the ground and air stay colder.
