A toy car speedway is a fun and engaging activity for primary school children but also has plenty of opportunities for learning. This activity can be used to allow children to learn about the principles of gravity and friction and how they affect speed but also to practice a wide range of skills relating to maths, science, team work and communication.

## You will need:

• Practising timing the toy cars and how long they take to travel down the ramp.
• Race the toy cars down the ramp. Which of the cars is the fastest, can the children explain why.
• Try changing the height of the surface of the ramp to see whether this makes the cars go faster or slower. Can children see a pattern?
• Are there any other materials that the ramp could be covered with to effect the speed of the cars e.g. sand paper or bubble wrap?
• Try measuring the height and length of  the friction ramp. Can they use these measurements to calculate the gradient?
• Can children combine the time and distance to get a measurement of speed?

## The Science Behind the Toy Car Speedway

There are a number of forces acting together on the toy card speedway:

Gravity is the effect of pulling together of 2 objects and its strength depends on their mass (weight). As the earth is so large objects are pulled towards it (or downwards) by gravity. Some examples of gravity at work include an apple falling from a tree, a toy car moving down a ramp and water running from a tap. The effect of gravity on a larger or heavier apple will be greater and therefore it will fall to the ground quicker than a smaller apple.

Friction is a force that slows moving objects. It is greater on rough surfaces and less on smooth surface, therefore a rough surface will slow down the movement more than a smooth surface. This is why children move quickly down a slide because it has a smooth surface. The slide wouldn’t work as well if it was covered in grass.

Gradient is another word for the slope. The gradient can be calculated by dividing the horizontal length by the height of the ramp. The higher the number the steeper the slope. The steeper the slope, the greater the relative force of gravity and the less the relative impact of friction.

Can the children find any other examples of gravity or friction at work?

## Designing a Scientific Investigation

For a more advanced activity, children could design and carry out their own scientific investigation about gravity,  using the toy car speedway. Some useful questions to get started include:

• What hypothesis would you like to test? what do you expect to happen?
• What will be the variable and how will it be measured. Choose just one e.g weight of car, height or gradient of ramp, smoothness or ramp?
• How will the results be measured?
• What should be done to ensure that they are a fair test? (what needs to be kept the same?)
• What is the most appropriate way to present the data?
• Do the results prove or disprove the hypothesis?
• Using what you already know about gravity and friction, can you explain the results?

## This activity can cover the following areas of the Primary curriculum:

• Working scientifically – KS 1 and 2 – Setting up enquiries, making observations and measurements, presenting data, recording findings, using scientific language, drawing conclusions, making predictions, using evidence to support findings.
• Forces and magnets – KS2 – explaining gravity and friction
• Maths – KS1 and 2 – Measurement and statistics