Try this fun science experiment at home:

Materials

• Four index cards
• Four pieces of string cut into 12" lengths
• Double stick tape cut into 3" lengths
• Pen or felt tip marker
• Hole punch
• Magnifying glass

Procedure

1. Label each index card "inside", "outside", "outside 1", "outside 2".
2. Punch hole on one edge of each index card.
3. Tie a string through the hole of each index card.
4. Stick two 3" pieces of double stick tape on the unlabeled side of each index card.
5. Hang "inside" card on a light fixture inside your home (example: light fixture).
6. Hang remaining three cards in three different areas outside (examples: from a tree, fence, lamppost or gutter). Be sure to write down and remember where you hung all of your cards.
7. After 48 hours (two days), take cards down and look at them using a magnifying glass. Compare and contrast what you observe.
8. Answer these questions: Which card had the most dirt particles? Why do you think this card had more particles than the other? Are the particles different sizes? If yes, why do you think they are different sizes?
9. Where do you think the dirt particles came from?