Choose one task, model or clip within the current lesson stage. These resources support the existing two separate 40-minute lessons; they do not add another lesson or extra time.

Week 4 · Monday: Levers, pulleys and gears

Name: ____________________ Date: ______________

Worksheet PDF

Include worked explanation when printing

We Do · think together

Mechanism detective

Match each example to a mechanism, then give the deciding feature.

Use the model to explain or predict. Only record observations and practical steps that actually happened.

A: A seesaw turning on its middle support.
B: A rope over a fixed wheel lifting a flag.
C: Two toothed wheels turning together.

Discuss, point, draw, write or dictate a first explanation. Choose one example first; extend only if there is time.

Our first reason

Reveal a worked explanation after an attempt

A is a lever: a bar turns around a pivot. B is a pulley: the rope passes over a wheel and changes pull direction. C uses gears: the teeth transmit rotation. A name alone does not explain the effect.

One change to our explanation

Give a smaller support cue

Look for a bar and pivot, a rope and wheel, or teeth. Point before naming.

Writing stays in this open page only. It is not saved or sent. Copy any record you want to keep before leaving.

Apply it

Use the current workshop

Sketch and label a lever’s pivot, effort and load. Explain one change made by a fixed pulley or a pair of gears.

Teacher model · compare with the pupil’s evidence

A lever turns around the pivot; effort is applied to lift or move the load. A single fixed pulley changes the direction of the pull. Meshing gears turn in opposite directions and can change turning speed and turning force.

I Do · explain and model

Look, explain, check

A simplified teaching model. Distances, sizes and arrow lengths are not measurements unless explicitly stated.

A lever is a rigid bar turning around a pivot. Mark the effort and the load.

A fixed pulley can let a downward pull lift a load upwards.

Meshing gears have teeth that transmit turning. Different sizes trade turning speed and turning force.

Connect the ideas

For the same load, a longer effort arm on a lever can reduce the effort needed.

The effort then moves through a greater distance for the same load rise.

For meshing gears, a smaller driven gear turns faster but supplies less turning force in an ideal system.

Quick check

A fixed wheel at the top of a flagpole changes the direction of the pull. Does it automatically halve the effort?

Check the explanation

No. A single ideal fixed pulley changes the pull direction; it does not by itself halve the effort.

Optional clip or still

Watch the gear teeth

Question: Find two meshing wheels. How do their teeth transmit movement?

Optional local clip. Play only when ready; the question and still scenario also work without playback.

The same science without video

One frame from the supplied clip. The still identifies the apparatus; use the described scenario to reason about motion.

Imagine the driver gear turning and one tooth pushing the neighbouring gear tooth. In this directly meshing pair, what turning direction must the neighbour have? Use the model to explain; the still does not measure speed or force.

Teacher explanation for the video or still scenario

A tooth pushes a neighbouring tooth, transmitting turning. Directly meshing wheels turn in opposite directions. The close-up does not by itself measure force or establish a gear ratio.

Use a short extract or the still scenario in place of part of the modelling time. A video or model is not evidence that pupils completed a practical.

For the adult

Preparation and a likely misconception

Use the labelled diagram and an adult-held ruler lever with a light secured load. Keep fingers away from any moving gear teeth or pulley. Do not open paint tins or use pupils as seesaw loads.

Watch for: The inherited wording can imply greater force and greater speed together. Explain the trade-off and distinguish fixed pulleys from pulley systems.

Exit question and model answer

What should you ask when a mechanism makes a task feel easier?

Reveal a worked explanation after an attempt

What changed, what stayed the same, and whether the effort must travel farther or the output moves more slowly.