Before we get lost in our exciting homeschool science experiments, let me teach you some things that air pressure can do. The air around you has weight, and therefore it exerts a force on your skin and on everything around you. This force is called air pressure. When the air pressure on an object is the same from all sides, the object is stationary, but as soon as the air pressure changes a little, the object will move- making it seem like magic.The cool breeze you enjoy at the beach is due to a difference in air pressure. When this difference in air pressure gets greater, it can cause cyclones and tornadoes. In the following homeschool science experiments I will show you that air pressure can do some things that are rather magical and contrary to what you expect.Upside Down Water Glass Trick: Fill a drinking glass with water till it is one-third full. Now place an index card or a cardboard on its mouth. Next, turn the glass upside down while holding the cardboard in place with your left hand. If you now release your hold on the piece of cardboard, what will happen? The obvious answer that comes to our minds is that the cardboard will fall and the water will get spilled all over the place.
 
Now release your left hand, while still holding the glass upside down with your right hand. What happens? Magic! The cardboard refuses to fall, holding the water in the upside down glass- exactly opposite of what you thought! How did this happen?
 
Let me reveal the secret! Remember that the weight of air or air pressure at sea level is almost 15 pounds per square inch (psi). This force of 15 psi is actually pushing the cardboard upwards. Now the weight of the water and air in the glass is pushing the cardboard downwards, but is too weak for the atmospheric pressure of 15 psi. The cardboard piece cannot move upwards, and therefore sticks to the rim of the glass.
 
Now we move on to yet another exciting and mind-boggling homeschool science experiment, shall we?
 
The Ping Pong Ball that Won’t Float: And you thought only you could be stubborn; wait till you see the  ping pong ball in this experiment. Take a funnel with its broad mouth pointing upwards and place a ping pong ball in it. Your goal is to get under the funnel and blow upwards in order to make the ball float. Begin! What happened?
 
Try again! Disappointed aren’t you? The ping pong ball won’t float- exactly the opposite of what you thought. How come?
 
Here’s the answer: When you blow air, it moves at a high speed. Air moving at a high speed just wants to rush by and does not bother to push objects in its path. Therefore there is low air pressure under the ping pong ball. The air pressure above the ball is- you’ve guessed it right- 15 pounds per square inch. This air pressure pushes the ball back into the funnel.