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Year 3 Science

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A Simple Machine - The Inclined Plane

inclined plane

The world we live in today depends on many tools. With tools, we build and dig, we lift and cut, we grip and carry. What tools can you name? Did you think of a hammer, screwdriver or pliers? What's a hammer for? To whack in a nail. What's a screwdriver for? To twist a screw. What are pliers for? To grip and pull. With the right tool, you can do a lot more than you can with just your hands alone.

We use tools to help us do things; we also use machines. When you hear the word 'machine', you may think of something like a sewing machine, or a washing machine, or a bulldozer. Those are one kind of machine, but there's another. We call this other kind simple machines. They make a lot of work easier for us to do. Let's learn about the inclined plane, which is a simple machine that helps people every day.


The Inclined Plane

Imagine you're pushing a heavy load in a wheelbarrow—maybe your sister and your dog (be careful, now!), or a pile of rubble you've collected. You come to a kerb, and you can see that it's going to be hard to push your loaded wheelbarrow up that kerb. How can you get the wheelbarrow up the kerb easily? Luckily, you see a wooden plank nearby. You place it so that your wheelbarrow can roll right up the plank and over the kerb. There, that was easier!

When you used that plank, you made a simple machine called an inclined plane. 'Inclined' means slanted or leaning. A plane is a flat surface. When you pushed your wheelbarrow up the plank, the inclined plane helped spread out the work of lifting the loaded wheelbarrow over the kerb.

Did you know that a wheelbarrow is also a machine? It is a lever attached to a wheel and axle (learn more about these three other simple machines in What Your Year 3 Child Needs to Know. The handles are a lever to help you lift the load. The wheel lets you roll the load once you have lifted it. Rolling a wheelbarrow up the plank is three machines working together.

People in wheelchairs also use inclined planes—ramps. Ramps make it possible for people in wheelchairs and for people with baby buggies to get in and out of buildings, and to roll smoothly on or off a pavement. Look for these inclined planes at the buildings near where you live.

At home or in your classroom, experiment with ramps and inclined planes. Either with a set of blocks or using items around your house (books, cereal boxes or tissue boxes could be good for this), experiment with making a ramp from the ground up to a higher level. Can you make a set of stairs with your blocks and make a ramp up them? Use a toy car if you have one to see how the ramp helps it zoom to the top of the stairs!


This activity is adapted from pages 312 - 316 of What Your Year 3 Child Needs to Know, which can be purchased here.