Equipment

Airtrack
AKA: Friction Free Apparatus

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Fig 1: Basic Airtrack kit including blower and trolleys
Fig 1
Fig 2

Summary

The airtrack consists of a long metal tube with holes along its length. Air is blown from a pump into the tube. The air which escapes through the holes provides a near friction free cushion which gliders can ride on.

Operation

Making sure the airtrack is placed on a completely flat surface, the blower (a small high output air pump) is connected to one end of the tube via a hose. Gliders (V-shaped pieces of metal) are placed on top of the track. When the pump is turned on, the gliders will ‘glide’ on a cushion of air just above the surface of the track.

Gliders move with very little friction and therefore if pushed, will travel at a near constant velocity for a surprisingly long time. This is the basis for Newton’s first law of motion.

The airtrack is essential for demonstrating principles such as acceleration, velocity, change in momentum and measuring speed. When used with light gates and dataloggers, very accurate readings can be produced. It can also be used to effectively show how energy is transferred during collisions and can be used to show the power of magnetic fields. Masses and magnets can sometimes be added to the gliders during these investigations.

Setting up needs to be fairly precise. Make sure the airtrack is as flat as possible using a spirit level (some models have one built in). This ensures the gliders have no bias.

Ensure any rubber bands are new and strong enough (having been left in the storeroom for a while, rubber bands become brittle). The gliders have to run smoothly over the surface of the airtrack and so both need to be clean and dry and free of scratches or dents. It is important when moving the airtrack not to bend or buckle the sometimes thin walls of the device. If the surface is warped only a small amount the glider may not be able to move fluidly.

Safety

 CautionEnsure the air input cavity on the blower does not become obstructed as overheating may occur.

The contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.