What you need:
- 4 tuna, or similarly sized, cans with top and bottom removed
- 1 sheet of colored construction paper
- 4-inch-square filters (clear plastic wrap, waxed paper, newspaper, gauze, cloth, aluminum foil, etc.)
- tape
What to do:
- Invite your child to choose at least three different kinds of filters to use in this experiment. Tape three filters onto each can, leaving one can uncovered.
- Divide the construction paper into quarters.
- Label one square "No Filter" and the others with the kind of filters you chose. Ask your child to predict which filter will block out the most sunlight and which will block out the least. Be sure to write down both of your predictions.
- Put the cans on top of the corresponding squares and carefully tape them in place. Set the construction paper and filters in a sunny windowsill.
- Leave the filters in the sun for a week. Then remove the filters and compare the results. How close were you to your predictions? What happened to the paper with no filter?
- Discuss with your child how the filters are like the ozone layer — they block out some of the sun's rays. You might want to use library or Internet resources to find out more about the ozone layer and how people can help preserve it.
Learning benefits:
- develops observation and experimentation skills
- explores how the ozone layer filters the sun's rays
