Opening

BUILD · SCIENCE · Lesson 7 of 7

Which surface should stop the sliding block sooner?

Learning intention

Compare a sliding block’s movement on different surfaces and explain the effect of friction using a controlled test.

Predict from evidence.

Keep the release the same.

Success looks like

Describe friction opposing this block’s sliding.
Compare repeated run-out distances.
Name the changed surface and important controls.

Retrieval

BUILD · SCIENCE · Lesson 7 of 7

Retrieve pushes, pulls and comparisons

1. What can a push change?

2. Name one thing to keep the same in a test.

3. What unit can measure a short distance?

I do

BUILD · SCIENCE · Lesson 7 of 7

I distinguish motion from force

The block slides right.

Friction on it acts left.

Contact with the surface matters.

Friction opposes sliding at the contact

Diagram description

A wooden block is already sliding to the right on a stationary horizontal surface after leaving a ramp. Friction on the block points left. The movement arrow is distinct from a force arrow; vertical forces are omitted from this simplified focus diagram.

I do

BUILD · SCIENCE · Lesson 7 of 7

I keep the start conditions fixed

Same block, face and ramp.

Same release mark; no push.

Change only the level surface.

Change the horizontal test surface only

Diagram description

Side-view fixed ramp feeds a sliding wooden block onto a horizontal test surface. The same block is released without a push from one marked point; ramp angle, release point, transition and block face stay fixed. Run-out is measured from the ramp end to the same chosen block edge when stopped.

Continue within this stage’s shared time.

I do

BUILD · SCIENCE · Lesson 7 of 7

I use repeats before choosing

Compare all three runs.

A longer run-out means less slowing here.

Compare distance after the same release

Diagram description

Horizontal bars start at zero and show constructed means: card 60 cm, cloth 23 cm, rubber 15 cm. They summarise three supplied repeated runs on each surface, not universal material constants.

Continue within this stage’s shared time.

We do

BUILD · SCIENCE · Lesson 7 of 7

The surface-selection meeting

Go to interactive investigation

Read the three runs.

Choose the shorter stopping zone.

Use two readings in your reason.

Constructed sliding-block data; same ramp, block face and release
Surface	Run 1 (cm)	Run 2 (cm)	Run 3 (cm)
Card	58	60	62
Cloth	22	23	24
Rubber	14	15	16

My response — say it, sketch on paper or type

Replay the surface evidence

Choose a surface and reveal the supplied run-out. This is a data replay, not a timed physical simulation. The paper table gives every run.

Compare stopping-distance records

Constructed means of three runs. Same wooden block/contact face, fixed ramp and flush transition, marked release without a push. Change only horizontal test surface. Distances describe this setup, not universal material constants.

This is an illustration of the supplied endpoint, not a force or speed simulation. It cannot predict a new surface. With reduced motion, use Show endpoint.

Decision 1 of 3

After release the block slides right. Which way does friction on it act?

Choose, test, then explain together. Evidence diagrams appear only after your test. Diagram transitions explain the model; they do not represent real elapsed time. Use Pause model to stop transitions and model controls, or your device’s reduced-motion setting. The printed We do activity provides the paper route.

We do

BUILD · SCIENCE · Lesson 7 of 7

Repair a changed release

A team pushes only the rubber run.

Can we compare it fairly?

Name the repair.

My response — say it, sketch on paper or type

Hinge

BUILD · SCIENCE · Lesson 7 of 7

The block slides right after release.

Which friction statement fits this setup?

You do

BUILD · SCIENCE · Lesson 7 of 7

Choose your science route

Read and select a surface.

Write an evidence-based recommendation.

Review the strength of the test.

My response — say it, sketch on paper or type

You do

BUILD · SCIENCE · Lesson 7 of 7

Make your own evidence record

Use the shared evidence.

Explain one choice.

Check a label or number.

My response — say it, sketch on paper or type

You do

BUILD · SCIENCE · Lesson 7 of 7

Check what the evidence can show

Point to the clue you used.

Remove an unsupported claim.

My response — say it, sketch on paper or type

Continue within this stage’s shared time.

Review

BUILD · SCIENCE · Lesson 7 of 7

Lundy loop: improve the shared account

Choose how to share.

Hear one evidence-based challenge.

Improve or defend one idea.

What made our surface choice defensible?

My response — say it, sketch on paper or type

Review

BUILD · SCIENCE · Lesson 7 of 7

Keep the useful change

What changed in our account?

Which evidence helped?

My response — say it, sketch on paper or type

Continue within this stage’s shared time.

Exit

BUILD · SCIENCE · Lesson 7 of 7

Three final checks

E1. What does friction oppose in this test?

E2. Which supplied surface gives the shortest run-out?

E3. Name one start condition to keep the same.

My response — say it, sketch on paper or type

My science task sheets

Choose one route with your teacher. Shared evidence and the exit sheet appear in every route. Your work stays here while the page is open; save it before closing.

Shared evidence • Constructed surface test

Same small wooden block and contact face; fixed low ramp and release mark; no push. Only the level test surface changes. Measure from ramp end to the same trailing block edge at stopping.

Surface	Run 1 (cm)	Run 2 (cm)	Run 3 (cm)
Card	58	60	62
Cloth	22	23	24
Rubber	14	15	16

Mean run-out: card 60 cm; cloth 23 cm; rubber 15 cm. These are summaries of supplied teaching data, not universal properties of every material pair. Friction opposes this block’s sliding.

W1. Which surface best fits a short model stopping zone? Use evidence.W2. Why must we repair a run given an extra push?

Route 1 • Choose using the readings

Word bank: rubber / card / same / opposite / cm.

S1. The shortest run-out is on... Card Cloth Rubber

S2. Give one reading supporting your choice.

S3. The block slides right. Friction on it acts... Right Left

S4. Name two things the fair test keeps the same.S5. Would you give one run an extra push? Why?

Route 2 • Write a surface recommendation

Recommend a material for this model stopping zone, using repeated evidence.

M1. State the changed factor and measured outcome.M2. Compare card and rubber using their repeated ranges.M3. Explain friction’s direction and effect after release.M4. Write a short method with a consistent release, distance rule and repeat.

Route 3 • Review the test quality

A designer claims: “Rubber always has the most friction, so our result proves the safest surface for every purpose.”

T1. Limit the claim to the actual object and setup.T2. Explain why a different material pair or condition could need a new test.T3. A model needs a long sliding distance instead. Which supplied surface fits that purpose?T4. One cloth strip bunches up and stops the block. How should the team record and investigate this?

Exit and reflection

Point, draw, write or tell an adult.

E1. What does friction oppose in this test?E2. Which supplied surface gives the shortest run-out?E3. Name one start condition to keep the same.R1. Which idea did you improve or defend? What evidence helped?R2. What useful question would you investigate next?