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Lesson · Grade 5 · Science

Ramps, Wedges and Screws

  • Grade 5
  • Science
  • 1 min 15 s
  • British Columbia
  • BC5-SC-11

A ramp lets you lift a box with less force by pushing it a longer way, and two ramps placed back to back make a wedge that turns a push down into pushes that split a log apart. A long ramp wrapped around a post becomes the thread of a screw, so a small turn pushes the screw into wood: wedges and screws are ramps in disguise.

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In one sentence

The question this lesson answers

What do a ramp, a wedge and a screw have in common?

A ramp, or inclined plane, is a slope.

Transcript

What the lesson says

What do a ramp, a wedge and a screw have in common?

A ramp, or inclined plane, is a slope.

Lifting a heavy box straight up takes a big force.

Pushing it up a ramp takes less force.

But the box has to go a longer way to get up.

Now put two ramps back to back.

Together they make a wedge.

Push the wedge down into a log.

Its sloping sides push the wood apart.

So a wedge turns a push down into pushes out to the sides.

Now wrap a long ramp around a post.

Its slope winds around to make the thread of a screw.

Each turn moves the screw only a short way into the wood.

So a small turning force pushes the screw in hard.

So a wedge and a screw are really ramps in disguise.

Curriculum

Where this fits

British Columbia, Grade 5

Science, Physics: properties of simple machines and their force effectsBC5-SC-11

Previous: Pulleys: Changing the Direction of a PullNext: Complex Machines: Simple Machines Working Together

The outcomes and strands follow the British Columbia curriculum.

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