A CENTS OF FLOATING

Objective: Students should build a raft which is sufficiently stable not to sink.

Props: 10 drinking straws for each team of two,

50 inches of masking tape for each team,

1 or 2 pans with about one inch of water in them

100 pennies.

Step by step instructions

1. Have each student in your group pair up with a partner.
2. Give each team 10 drinking straws and 25 inches of masking tape.
3. Explain that they will have seven minutes to design and build a raft. They may only use the straws and masking tape that they were given.
4. The object is to build the raft so that it will hold the most pennies before sinking.
5. When they are finished, they are to bring the raft up to the pan of water for their “official float.”
6. Have the teams build their rafts.
7. Do not let them try to see how well they float before the official float. They may use the entire seven minutes you have given them, or they may come up and do the official float before the seven minutes are up.
8. For the official float, they will put their raft in the pan of water. Then the team members themselves will take pennies and place them one at a time on the raft. They may put the pennies anywhere on the raft that they want to. They will keep adding pennies, one at a time, until the raft goes under water. The total number of pennies on the raft before it sank is their official total.
9. Now give them a second try. They will have to use the same ten straws, but you can give them a new 25 inches of masking tape. All of the rules stay the same for the second try.

 Debrief

1. How many pennies did you float on your first try? Your second try?
2. Was it hard for you and your partner to agree on the design?
3. Did you stick with your original design concept? If not, what changes did you make?
4. Did you watch other teams to see what they were doing? If you looked, did you get any good ideas from them?
5. Is it permissible to watch others and get good ideas or should all of your ideas just come from you and your partner?
6. Is getting ideas from others called “cheating?”