Each group needs:

• 1 ft² (0.1 m²) piece of cardboard
• 1 tennis ball
• 4 aluminum cans
• 12 sheets of newspaper
• 4 750-ml plastic bottles (such as soda bottles)
• 6 plastic yogurt cups
• 5 ft (1.5 m) string
• 5 ft (1.5 m) masking tape
• 1 pair of scissors
• 1 stopwatch
• Recycled Towers Worksheet, one per student

To share with the entire class:

• fan
• computer with projector to show the Recycled Towers Presentation