Ramps, gradients and friction

Today's activity is all about ramps, gradients and friction. We're going to investigate how the distance travelled by a toy car is affected by the gradient of the slope and the surface of the ramp.

You'll need

A ramp - we used a shop bought ramp set, but you could make your own with cardboard or wood and a stack of blocks or books.

Carpet or another rough surface.

Cars - LEGO or DUPLO work well.

Chalk

Tape measure

ramp with two DUPLO cars at the top ready to race down for a gradient and friction investigation

Things to think about

We're investigating two different things in this activity, so we need to be very careful to only test one at a time and keep the other variables constant.

Do not push the car, just let it go without any force behind it.

Method

How does gradient affect distance travelled?

Variables to keep constant

Use the same car and the same ramp.

Record the distance travelled using chalk by the car for three different gradients, what do you notice?

DUPLO cars at the top of a ramp covered in carpet for a friction investigation

How does the surface of the ramp affect distance travelled?

Keep the car and gradient constant this time, but record the distance travelled using a smooth and rough surface on your ramp. What do you notice?

The rough surface could be bubble wrap, carpet or a large sheet of felt.

Gathering data

We repeated each test 3 times and found the average distance travelled by the cars then recorded the data in a table.

Results

Our cars travelled further if the gradient was steeper, this is because a steeper gradient allows the car to pick up more speed.

The cars travelled less far when we used the carpet surface than when we used the smooth surface. This is because there is more friction between the car and the carpet than between the car and the smooth surface.