Experimenting with Forces : Building a Balloon-Powered-Cardboard Wagon & Testing it on Different Surfaces!

Please download and print the illustrated child-friendly instructions with information about Materials, Tools, Assembly, Experiments.  You'll also need to print the wagon template onto card and follow the instructions: 

MATERIALS = Balloon, Straws, Corrugated Card cut to size of Chassis (14cm x 5.5cm), Barbecue Skewers/dowel (pre-cut by adult to 7cm long), printed wagon template on card, 4 wheels (wooden ones can be ordered eg  or use plastic milk bottle tops or similar), different sorts of material for tyres and track to experiment with forces and friction (eg carpet, sand paper, wood, lino, perspex).

TOOLS = scissors, sticky tape, blu-tak, felt tips or colouring pencils (if you decide to decorate your wagon), and a stop watch for testing the wagon on different surfaces.

ASSEMBLY = put the wagon box on top of the chassis and hold them together with sticky tape.  Then use tape to secure the neck of the balloon to the roof of the wagon.  Arrange it so the straw sticks out the back of the wagon. As the gas escapes backwards from the balloon it produces a force on the wagon which makes it move forwards.

EXPERIMENTS = take your wagon to the test tracks.  Blow the balloon up and set your wagon off on the track!  Try it on a rough track and then a smooth track.  On which track does it run fastest?  Why do you think that is? Now fit different sorts of material to the wheel for tyres with a dab of glue and see how different sorts of material affect how fast the wagon goes.  What sort of material  helps it go faster?   then think how air moves around your wagon when it is moving.  How could you change the shape of your wagon to help air move around it more easily so it goes faster?


Friction is the force between two surfaces sliding against each other.

Friction works in the opposite direction to the motion of a moving object and slows it down.  For example, if you push a block of wood across a carpet, friction slows down the forward movement.

Rough surfaces produce more friction.  Smooth surfaces produce less friction.  For example, ice is very smooth, and it is easy to slide on it because there is little friction.

Heat is produced by friction.  For example, you can rub your hands together and they get warm.  You can rub two sticks together to make a fire.

Air resistance is a type of fricion when air surrounding a moving object slows it down.

Engineers use friction when designing vehicles, tyres and roads.  For example, friction makes brakes work, and stops tyres skidding.

Engineers sometimes need to reduce friction. For example, cars and aeroplanes are designed to be 'streamlined' so the air flows around them as easily as possible and does not slow them down.




How to make a balloon Powered Wagon


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