1. Divide students into 6 groups. Each group will get 1 lettuce leaf or 1 kale leaf.
2. Poke 2 holes on either side of the cup, near the top. Thread one end of the string through the holes. Thread the other end of the string through the paper clip. Tie the ends of the string together.
3. Assign a student to hold the leaf so the tip is facing down. (Make sure to hold it still!)
4. Use a paper clip to poke a hole about an inch from the top of the lettuce leaf. Put one prong of the paper clip through the hole so the paper clip and cup hang down from the leaf.
5. Add pennies to the cup one at a time. Keep adding them until your leaf rips and the cup drops.
6. Weigh the cup with the pennies inside. Then weigh the empty cup. Record each weight in grams.