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Builder's Lab / Week 07 / Tuesday
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Week 07 · Marble Run

Tuesday

Gravity, slope and friction
// A marble run that takes 5 seconds or more
⏱ about 20 min

Tuesday: Gravity, Slope and Friction

Raven props a book ramp up high, then low.

Rocket rolls a marble down each one.

"The high ramp is faster!" Rocket says.

Then Raven lays a towel on the low ramp. The marble rolls even slower.

Nova hums. "I found a pattern. What do you notice?"

Gravity pulls

Gravity pulls the marble down the ramp.

On a steeper slope, the marble goes faster.

On a gentler slope, it goes slower.

Friction slows

Friction is a force that slows things down.

A rough surface, like a towel, makes more friction.

A smooth surface makes less friction.

Try it
Make a book ramp. Roll a marble down.
Make it steeper. Roll again.
Which was faster?
Safety first
Marbles can choke little ones. Keep them away from babies and toddlers.
Marbles never go in your mouth.
Pick up every marble so nobody slips.
RAMP CHECK
  • Read the question.
  • Tap your answer.
Which ramp makes the marble go faster?
What pulls the marble down the ramp?
IdeaTrue or false?
Friction slows a marble down.?
A towel makes less friction than a smooth book.?
A gentler slope makes a marble slower.?
WHY THIS EXERCISESlope and friction are tools for slowing the marble.

Two tools to slow a marble

  • Tool 1: a gentler slope. Less steep means slower.
  • Tool 2: more friction. A rough surface slows it.
  • Too gentle or too rough, and the marble may stop.
SLOW IT DOWN
  • Read the question.
  • Tap your answer.
Raven puts a towel on the ramp. What does the towel add?
Which surface makes less friction?
A ramp is so gentle the marble stops. What went wrong?
Which force makes a marble roll down at all?
FASTEST TO SLOWEST RAMP
  • Start with the fastest.
  • Tap a card, then tap its spot.
1Fastest
2Middle
3Slowest
Try it
Make a gentle book ramp.
Roll a marble down it.
Lay a towel on it and roll again.
Which roll was slower?
Safety first
Keep marbles away from babies and toddlers.
Pick up every marble.
Draw your two ramps. Show which one was slower.

You know how to slow a marble!

Tomorrow, we build version 1.

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