Airflow
Calm amidst the storms.
Safety
- Carefully review the general safety advice on the back of the box cover before starting the experiment.
- Read the "Working with Batteries" section of the safety guidelines carefully before proceeding. Always disconnect the setup after finishing the experiment.
- Disassemble the setup after the experiment.
Step-by-step instructions
The perforated plug—the flow straightener—changes the direction of the air flow coming from the propeller. Protect the propeller with a restrainer.
Turn on the propeller and watch the ball levitate!
Do you want the ball to hover even higher?
Which ball will win and be able to stay in the stream?
Disposal
- Dispose of solid waste together with household garbage.
- Dispose of used batteries in accordance with local regulations.
Scientific description
As they collide with solid objects, the moving parts 
of the air change their direction 
. Therefore, as it passes through the flow straightener 
, the vortex 
transitions into a straight upward flow 
.The flow consists of air parts accelerated by the propeller 
. These parts slow down when they collide with the still air around them. The farther the flow travels from the propeller, the more collisions it experiences, and the more it weakens.
The straightened flow pushes the ball 
upwards, while gravity pulls the ball down. As a result, the ball hovers at the height where the flow force is strong enough to hold it. The ball cannot hover at other heights. When colliding with the ball, parts of the airflow go around it and support it in the center. Two identical balls 
cannot stay in the stream because they are competing for one spot. As a result, one of the balls 
will take this place, and the second 
will fall out of the stream.
When the pipe is installed, the ball can hover at a greater height. The flow is not weakened as much in the pipe, as this limits its contact with the surrounding air.
