Skimmer Regatta 1

Force and Motion

Students are introduced to the air pump, which is used to power the skimmer. They experiment with where to aim the airstream.

• Define force as a push or a pull.
• Experiment and use data to conclude the most efficient way to direct a given supply of air to move a paper skimmer as far as possible.

Newton's first law of motion - the law of inertia - briefly says that an object at rest tends to stay at rest and an object in motion tends to say in motion in a straight line and at a constant speed unless it is acted upon by an unequal force. A force is a push or a pull. The paper skimmer used in this series keeps still by the force of inertia until the student applies a push or a pull to move it. The force of the push or pull is stronger than the force of inertia and resistance of friction. The forces affecting the skimmer become unbalanced and the skimmer moves in the direction it is being pushed or pulled. Inertia keeps the skimmer moving for a time after the push or pull force ends. Friction eventually stops the skimmer.

Air will be the force (push) that students will use to move their skimmers. Directing air at the skimmer so that its force is distributed evenly against the skimmer will keep it moving forward.

NOTE: Skimmers must be constructed before class.

Have students complete Steps 1-4 of the Explore activity in their teams. Be sure every team has correctly labeled their cardboard strip and every student has a record sheet or a copy of the Skimmer Regatta Design Team Log.

Have a student read Challenge! aloud. Tell students they have five minutes to work on the Challenge! activity. After five minutes call an all-class Think Tank meeting.

1. Ask several students to read their record sheets. Record their data on the chalkboard.
2. Help students understand that all of their suggested methods of moving are either pushing or pulling. Challenge them to think of a nonpush or nonpull method. Point out that blowing is pushing and that lifting and carrying are pulling (lifting) and pushing (carrying).
3. Tell students that any kind of push or pull is a force and that force causes movement. On the chalkboard, write "Force is a push or a pull." Invite students to create a poster illustrating this concept.
4. Ask students to name some forces that make objects move. [Wind (pushing); water (pushing); gravity (pulling); springs (pushing); muscles (pulling); explosions (pushing); magnets (pushing or pulling)]
5. Tell students that wind is a natural force and is one of the first forces people learned to use to help them move objects. Explain that people had to experiment to learn how to make the best use of wind force. Stress that some of the information learned about wind force helped people understand and use other forces.
6. Throughout this program, students are asked to do three trials and figure the average result. If you need to review finding averages with your students, now is the time to do so.
7. Have one student read the introduction of the investigate section. Check for students' understanding. Tell students they must use the same amount of air from the balloon each time they test their skimmer. Tell them they will measure the distance around the balloon with string to make sure the balloon is the same size each time they blow it up. Tell students to return to their teams and investigate to find the best way to direct air to move their skimmers as far as possible. Remind students to read each numbered question, experiment to find the answer, and copy and complete the Design Choice Record. You may choose to have students use the record sheets found in the Skimmer Regatta Design Team Log.

Circulate among teams to check on their progress. Make sure students keep the nozzle of the air pump behind line A at all times. Encourage cooperative problem solving, creative experimentation, and neat and thorough record keeping. Make sure everyone gets to participate.

Cut a 9 cm x 12 cm rectangle from manila art paper or an old file folder. Fold each side in (about 1 cm), then unfold to form a crease. Cut on the diagonal from each corner to crease line. Fold all sides up and tape to form a box. Make two skimmers for each team.