Lesson 1: Will It Roll?

45 minutes

Setup

Set up space for Racer Ramps. Secure the upper ends of the ramps to chairs (all at the same height) so that when racers roll down, they have plenty of space for trial runs (+/- 20 ft for hard floor, +/-15 ft for carpet). A nearby playground or gym or hallway would work if there isn’t space in the classroom.

Collect the materials for building racers in accessible classroom location. Each team gets one car body, one bamboo skewer, and access to all the non-consumable tools, as well as tape, hot glue, scissors, markers etc.

Collect the measuring devices in accessible location, not distributed to teams (teams will come get what they want to use to measure).

Have the timing device available to time the 35 minutes of work time. It is your choice whether to display the timer, or call out time reminders; it is also your choice to decide how strict to be on the timing.

Narrative

During this activity, students in their teams will build racers from the supplied materials, aiming to construct one that will travel at least five feet from the bottom of the ramp when released. The students will spend their time talking about and grappling with mechanical aspects of the building: How to get the wheels to spin? How can we make it go farther, or straighter? Productive struggle and shared discovery is the goal, not a quick path to a “successful” racer.

Launch

• Teams of 3
• Hand out lab sheets
• Introduce their task (see task statement)
• Point out the materials and the ramps and invite them to come see (but not yet touch) what is available.
• Emphasize that gravity is the only propulsion method allowed—no pushing
• 3 minutes of solo think/sketching time.
• 35 minutes of building time as a team (scouting encouraged after 15 minutes)
• You can try your racer on the ramp any time
• Open source ideas: If another team comes looking, you have to show them what you are trying.

Task Statement

Your challenge is to build a racer that will travel at least five feet from the bottom of the ramp, when you release it (without pushing it) at the top of the ramp. You are limited to 4 wheels.

Orchestrating & Monitoring

It is important to focus on maker mindset-building time here: resist the urge to prompt them with solutions that you know will work. If teams struggle, encourage listening to others’ ideas, learning from what other teams are trying while scouting, and trying different things.

• Monitor staying on task and adhering to constraints:
  • Only 4 wheels per team.
  • No pushing at top of ramp
• Encourage:
  • Listening to others’ ideas
  • Trying different thingsv
  • Discussion about challenges
  • (after 15 minutes) Scouting other teams’ racers
  • Decorating their racers (helps build buy-in)
• Mathematical ideas
  • Measurement: How are students measuring their racers’ distance? In the discussion at the end, different techniques will be discussed. It is not necessary to have a consistent measurement technique at this stage, but it is useful if the teacher is aware of strategies in the classroom (issues: starting place, ending place--rear of car or front or?, and path--straight line or path of car)
  • It is tempting to direct students’ efforts with questions like “have you tried…?” Instead, ask “what is causing that problem?” This fosters students’ and teams’ productive struggle and independent troubleshooting, and helps break a pattern of student over-reliance on teacher problem-solving.
  • Allow teams to get another corrugated cardboard sheet and/or bamboo skewer (but not a third!) if they want to start over
  • Watch for, take photos/brief videos of, and make notes for discussion at the end:
  • Discussions about measuring: where to start (bottom of ramp); what path to measure (straight line vs path followed by car)
  • Discussions about how to make the racer go farther
  • Challenges overcome
  • Different alternatives tried
  • Noticings about what worked

Discussion

See lesson synthesis

Anticipated Solutions

See pictures for ideas about what might turn up. Bamboo skewers cut in half, inserted through the corrugations in the plastic, make good axles. Wheels with ⅛” holes fit tightly on the axles. Three-wheel and four-wheel designs are common.

Anticipated Misconceptions and Challenges

Some teams may have trouble getting their car to even roll down the ramp. Encourage them to scout what other teams are trying

Some students glue or tape their wheels so that they don’t spin. Encourage them to scout other teams and listen to other ideas in their team

Images for Classroom Use

Lab sheet

When most/all teams have racers that travel five feet, gather the class’s attention for a brief (5-10 minute) discussion to bridge to the next activity:

• Do you expect your racer to go exactly the same distance every time you run it?
• How many runs do you think it would take to have a good idea of what to expect from your racer?
• [Settle on at least 7; probably not much more because of time constraints]
• Did we all measure in the same way?
• What reasons can you think of for why it might be useful for us all to measure the same way? [primarily for comparability]
• If not all the same, discuss methods; and for next activity, settle on measuring from the bottom of the ramp to the rear of the racer in a straight line so that measurements are comparable. Settle on a common unit (inches or centimeters)
• Without modifying your racer, next time we will gather some data

Also next time, we want to explore simple changes we might make to racers, to make them go farther. What are some things you tried, or things we might try?

Record ideas, without evaluation, and have teams store their racers--unmodified--for next time.