Plants need sunlight to grow. Sunlight is also the main reason why leaves are green. Help the children find a small patch of green grass. Lay a one-foot square piece of plywood over the grass to block the sunlight from getting to it. Once a day, lift up the board and look for any color changes in the grass. Keep track of how many days it takes before the green color changes to white.
A magnet is a special rock or piece of metal that attracts other metals and pulls them toward it. We can't see this magnetic force, but we can see its effect. Help the children put different kinds of materials between a magnet and some paper clips to discover which materials can block this invisible force. Try cardboard, paper, glass, aluminum foil and plastic.
Ice turns to water when its temperature rises above 32 degrees Fahrenheit. The hotter the temperature, the faster the ice will melt. Light colored things reflect light, and dark colored things absorb light. When an object absorbs sunlight, it also absorbs some of the sunlight's heat. Place an ice cube in a cereal bowl and lay a piece of white paper over the top of it. Place another ice cube in a second cereal bowl and cover it with a piece of black construction paper. Set the bowls in a sunny window. Tell the children you are going to see if the bowl with the black construction paper absorbs more of the sun's heat than the bowl with the white paper. Have the children check the bowls every few minutes. If the bowl with the black paper absorbs more of the sun's heat, the temperature in the bowl will rise faster than the temperature in the white-covered bowl, and its ice cube will melt more quickly.
The sun, rain, wind and other weather elements can deteriorate many materials. Test the effect of the sun and weather on the ability of a rubber band to be stretched. Fill an empty soda can with sand. Loop a rubber band over a clothesline and around the can's metal opener tab so that the can will hang down from the clothesline. The rubber band is stretched. Leave it outside and take the children out to look at it once a day. Keep track of how many days it takes before the rubber band loses elasticity and develops cracks.
On a hot summer day, people sometimes sit in chairs or swing in hammocks under big trees because it is much cooler under the trees. Shade from trees is a natural air conditioner. On a hot, sunny day, hold a thermometer and stand in a sunny spot. Hold a small piece of cardboard or a playing card over the thermometer's bulb to keep the sun from shining directly onto the bulb. After two or three minutes, check the temperature. Now stand underneath a nearby tree and hold the thermometer for two or three minutes. Watch the temperature goes down.
On a large piece of paper, draw 30 circles. You can trace around a quarter to make the circles, and then number them from 1 to 30. Have the children look at the moon every night for one month. Each day, help the children shade in a circle to show how part of the moon was shaded the night before. The pattern will go from a moon that has no shading to being completely shaded and not being seen at all, back to being fully bright again. These are called the "phases" of the moon. When the chart is completed, notice that the shading goes from one side to the other.