Floating Ping Pong Ball Model

Quick Answer: The Floating Ping Pong Ball Model is a fan-driven demonstration in which an upward air stream inside a clear tube holds a ping pong ball floating at a steady height. A speed control lets students raise or lower the ball and see how drag from moving air balances the ball’s weight.

Keeping a Ball in the Air

The listing image shows the floating ping pong ball model as a boxed base with an on-off switch, an indicator light and a speed control knob, with a transparent tube standing on top over a small fan. When the fan runs, air is blown up the tube and the light ball rises. At the right fan speed the upward drag of the moving air equals the ball’s weight, the forces are balanced, and the ball hovers in place.

Turning the speed control changes the airflow and moves the ball to a new height. Inside the tube the ball partly blocks the flow, so air speeds up through the gap around it, and the ball settles where drag, weight and the pressure difference across it are in balance. If the ball rises out of the top of the tube into the open jet, it tends to stay centred in the stream, an effect usually explained with Bernoulli’s principle that faster-moving air has lower pressure.

A floating ball gives a visual starting point for balanced and unbalanced forces, air resistance and the pressure effects used in aircraft wings, spray guns and carburettors. The power supply and any spare balls should be confirmed at enquiry.

Care & Handling

• Keep small objects, paper and fingers out of the tube; the fan draws debris in.
• Start the floating ping pong ball model at low speed and increase gradually.
• Clean the tube with a soft cloth and mild soapy water, and dry it before refitting.
• Keep a spare ball, since a dented ball flies unevenly.

Demonstrations

• Showing balanced forces when the ball hovers at a constant height
• Changing fan speed to show how drag depends on air speed
• Comparing a ping pong ball with a slightly heavier ball of the same size
• Introducing Bernoulli’s principle, lift and the design of aircraft wings

Specifications

Why Choose LabEquip

Primary and secondary teachers use a floating ball model to introduce forces and air pressure with an effect that holds attention from the first second. LabEquip lists it in the STEM kits range, and the Bernoulli Equation Verification Apparatus takes older students on to measured pressure and velocity. Use the contact page for enquiries.

Frequently Asked Questions

Why does the ball stay at one height?

At that height the upward push from the moving air exactly balances the ball’s weight, so there is no resultant force. If the ball drops, it moves into faster air nearer the fan, the upward force grows and the ball rises again, making the position stable.

What happens when the fan speed is increased?

Faster air produces more drag, so the ball rises until it reaches a new balance point higher up the tube, or is blown out of the top if the air is fast enough. Lowering the speed lets it sink.

Why does a ball in an open air jet not fall out sideways?

If the ball drifts to one side, the airflow around it becomes uneven. The resulting pressure difference pushes it back towards the centre of the jet. This is usually explained using Bernoulli’s principle, that faster-moving air has lower pressure.

Would a heavier ball float too?

Only if the air stream is strong enough to provide drag equal to its weight. A ball of the same size but greater mass hovers lower or not at all, which shows students that the balance depends on both weight and air speed.

Is the model related to how aeroplanes fly?

It shows the same physics of moving air exerting forces. An aircraft wing is shaped and angled so that air flowing over and under it produces a pressure difference and deflects air downward, giving the lift that balances the aircraft’s weight.

Is the model safe for children to use?

Yes, under supervision. The fan is enclosed in the base, but students should not push fingers or objects into the tube. Switch off before removing or replacing the ball.

Last Updated: September 2026