To see how design effects a boat's speed and ability to carry cargo.
Three-fourths of Earth's surface is covered with water. One of the properties of water is BUOYANCY, how well something will float. An object which floats will move aside, or displace, enough water to weigh as much as that object does. Design effects function.
Teacher's Lab Notes:
The only thing you'll have to provide for this activity is a body of water to hold the regatta in. A child's wading pool works easily. You may also be called on for advice and encouragement during construction.
1. Construction materials: Wood, plastic, foam, paper, polystyrene.
2. Size: the size of your "lake" will determine the necessary size limits. For a pool that's 1 meter in diameter, a maximum size of 20 cm in length and width is appropriate. Boats larger than the limit should be penalized by adding time onto its fastest trial run.
3. There must be space to carry cargo.
4. Types of power boats: Sailboats which are powered solely by wind; Rubber-band Boats which are powered by one or more rubber bands attached to one or more propellers; Jet Boats which is powered by a balloon or other non-combustion jet (water jets, baking soda and vinegar, antacid tablets, dry ice). Either use all three methods or give students the option of only one power source.
5. Use class time to discuss motion, forces, and fluid behavior, and shipbuilding history and technology.
6. Have the students begin the regatta by making detailed drawings of their ideas. Remind them of the boat architect's drawings they saw at the Franklin Institute. The construction of the boats should take place at home, but have discussion and review of drawings in the class before the regatta.
7. Give three to four weeks for construction.
8. On race day, each contestant makes at least 3 trial runs in the speed category, against the clock. Time the boats from a starting signal until part of the craft touches a designated area at the opposite side of the pool. Use each entrant's best time to determine the winner.
9. Repeat the trial runs in the speed with cargo category. Have students load small weights such as pebbles, marbles, or pennies. Determine the winner. If there is time, have the students compete to find whose boat stays upright and afloat with the most weight.
10. Have an awards ceremony and for each category have ribbons, extra credit, or whatever is appropriate.
Have the students discuss how they saw that a boat's shape determines how fast it can go and how much it can carry. Did the boat which went the fastest look like the boat that could hold the most weight? What do you change or lose if you design a boat for speed versus a boat to carry cargo?
Most regattas have strict limits on the type of boats which enter. A good example is the Americas Cup. Research the controversy around the race where the American Team sailed a Catermeran, a two-hulled boat. The race sailed the regatta into the courts and an international controversy.
The speed trials in this activity were adapted from Robert McDonald's "Wading Pool Regatta" which appeared in March 1990 Science and Children, pp. 16-17. He offers wonderful suggestions to tie the regatta into mathematics activities.