Defy Gravity and make the glow-in-the-dark ball float mid-air while learning about bernouli's airflow principle. Perform interesting air experiments. Includes parts, ball and instructions. Requires two AAA batteries (not included). Recommended for age 8 years and up.
Some things to try once you assemble your Space Air Engine:
- Place the lightweight ball (like a table tennis ball) in the air stream and experiment with interrupting the airflow with your hand. When the air is flowing freely, how high does the ball ‘levitate’ above the top of the blower?
- Try blocking just part of the airflow with your hand or a card -- if the ball can still stay suspended, how high is it now?
- Adjust the angle of the blower slowly with the ball in the air stream, so instead of pointing straight up, it slowly tilts toward the side. How low can you make the angle and still suspend the ball? Fun challenge -- try to get the ball to fall out of the stream into a ‘target’ zone or container.
- Can you suspend just the light plastic dish in the airstream? What about the dish while it is holding the ball? If something is different now, think about the shapes and the airflow -- how could that make a difference?
- If you have another light ball, can you get more than one object suspended in the air stream? If you add a small weight to the ball (like a paperclip or penny taped on, or a little piece of clay) or if you have a heavier ball (like a bouncy ball), what happens then?
Bernoulli’s Principle is a rule that describes how fluids act. A fluid is just something that doesn’t hold its shape, so air and water are both fluids even
though water is a liquid while air is a gas, and they act similarly in some ways. When air (or any other fluid) is moving more quickly, you end up with lower pressure in that area. The air in the stream that the blower is blowing is moving faster than the air surrounding it, so the air in that air column is at lower pressure than the air around it. You probably noticed some wobbling as the ball floated in the airstream -- whenever it wobbles out toward the more stationary (and higher pressure) air, the higher pressure pushes the ball back to an area of lower pressure -- back in the air column, so it mostly doesn’t escape the flow.
Other things to try with Bernoulli’s principle:
- Blow up two balloons and attach them to short strings. Get someone to hold the strings to the balloons so they hang down and are close to each other but not touching (maybe a couple centimeters or an inch apart).Try blowing gently through the space between them and see which way the balloons move (in or out?) -- a straw may help direct the air if nothing is happening.
- Are there other things you could pull together (really you’re letting the air pressure push them together instead!) using this same trick?
- For heavier objects you could try using a hair dryer to move more air faster than you can, but lighter objects that roll will usually work best.