Friction

Is it helpful (good) for us?  Is it not helpful (bad) for us? 

Part 1: A Little Less Friction

Follow instructions in Forces and Rocketry book (p. 7-10) to play the air puck shuffleboard game.  In advance of class, the teacher follows procedure steps 1-6 but uses whiteboard markers directly on tables instead of butcher paper for the game board.

• As a class, read together Forces and Rocketry book p. 7, and observe the teacher demonstration of a toy car rolling down a ramp onto a table and stopping. 

• As a class, read together Forces and Rocketry book p. 8 "Overview" and then "Procedure" steps 7-15.  

• Students follow procedure steps 7-15 to play the game.

After playing, answer the following questions as a discussion and/or in your journal.

1. What does Newton's First Law of Motion say?

2. Newton said that an object should move in a straight line at the same speed forever.  However, on Earth things slow down and stop.  Why?

3. How is friction helpful (good) for us?

4. How is friction not helpful (bad) for us?

5. What are three ways to reduce friction?

6. Describe the differences between playing with a non-air and an air puck.

Optional: see this video for an explanation of classical mechanics theory and Newton's Laws.

Part 2: Frictionless Game

Follow the instructions in the Forces and Rocketry book (p. 11-14) to design a frictionless game.

See past student samples of Frictionless Games.

Part 3: Friction Movies

a: Magic School Bus

Watch Magic School Bus: Plays Ball (season 3, episode 5) - 22 minutes.

While you are watching, in your journal answer the following prompts at these times.

7:45 - Describe what would happen to one of your favorite activities if there were no friction.

15:00 - What are examples of forces (1 push and 1 pull) that you have used today?

22:30 (end) - How has friction helped you during this lesson today?

b: Bill Nye Friction

Watch Bill Nye Friction (Season 3, Episode 8). Complete the worksheet.

Part 4: How to Fall Out of a Plane

Read page 19 in the Forces and Rocketry book.  Then watch a few minutes of Skydiving highlights (start at 1:24).  

Follow this procedure:

1. Cut out 1 skydiver & attach a 2g flat clay backpack (this is the experimental control).

2. Have one person hold the skydiver and another person use the timer.

3. Drop the skydiver from a certain height when the timer starts.

4. Observe, measure and record the drop time (round to one-tenth of a second, like 0.7) on your assignment sheet.

5. Repeat steps 3-4 two more times.

6. Repeat steps 3-5 two more times with modifications to the skydiver.

   1. Modification Options: No backpack, 2 backpacks, squirrel suit, bending arms/legs, parachute, etc. **Include at least one parachute.**

7. Clean up: 2 clay balls in bag/tape/timer/parachute/scissors/calculator/books in bin, skydiver and paper scraps in recycling

Complete the How to Fall Out of a Plane assignment sheet, then debrief this as a class.

Optional at the end of class: at least one of the following movies: Mythbusters penny drop (1:20 to 13:40) or Objects falling crash course movie.

See this completed sample "How to Fall out of a Plane" assignment sheet here to use for debriefing answers with class.  For absent students: use this sample "How to Fall out of a Plane" data to complete the assignment.

Friction Extension: Bill Nye Friction

Watch Bill Nye Friction (Season 3, Episode 8). Create a worksheet with at least 12 questions for students to fill in while they watch this episode.