A simple hovercraft experiment.
Basic principle:
If we lift an object off the ground using air, we reduce the force needed to move the object.
- Attach a balloon to a piece of card using a small piece of tube.
- Inflate the balloon.
- Put the card on a flat surface and let go of the balloon.
- The air will rush out of the balloon and lift the card.
- It will be very easy to move.
Why does this happen?
It happens because the card is now longer resting on the surface so it is not affected by surface friction.
On a flat, smooth surface the object does not need to be lifted very far off the ground to reduce the surface friction but in reality most of the surfaces we want to travel over are not very flat or very smooth. To travel over rough surfaces the vehicle has to be lifted higher to clear obstacles.
The early 'craft did this by using hugh fans to blow an enormous amount of air beneath the 'craft to lift it several inches of the ground. The more modern solution to this problem is to use a flexible skirt. The skirt is attached around the 'craft and enables it to travel over uneven ground and to clear obstacles.