1.) Fill 2 liter bottle to the brim with water
2.) Place a deflated balloon over the mouth of the bottle
3.) Poke a small hole in the side of the bottle, bear the base, with a nail
4.) Observer the behavior of the balloon
5.) Lift the balloon up into the air and pull up on it several times until it gets pushed down into the bottle. Observer the distance the water travels through the hole as you are dong this.
6.) Once the balloon is inside the bottle and completely inverted, blow air into it to inflate it. Observe the distance the water travels through the hole as you do this. you can also poke it with your finger to observer the same effect.
7.) Give the bottle a good squeeze. observe the balloon
When the deflated balloon is place over the bottle, air pressure acting on it pushes it into the bottle. This is because any water that leaves through the hole creates a vacuum in the space above the water. Air can thus enter the space that the water formerly occupied.
Since air pressure is great on the outside of the bottle then on the inside, the balloon is pushed (Not sucked) into the bottle. However, there is a little air still left in the bottle, because it is never possible to remove all of the air, and a little air was likely present in the bottle from the beginning.
Initially, very little water will flow out of the hole, since the is only a small amount of air in the space above the water. By pulling up on the balloon, the water flow will immediately cease, since the air in the bottle will expand to fill a greater volume, causing it to exert less pressure. when the balloon is allowed to snap back into the bottle, it momentarily compresses the air in the bottle, causing it to exert more pressure and force the water out of the hole.
When air is blown into the inverted balloon, it servers to compress the air already in the bottle, causing it to exert a greater pressure and thus force water out of the hole. The same effect can be observed by poking at the balloon.
If the bottle itself is squeezed, the balloon will inflate and be forced out of the bottle. Water will also be forced out of the hole. This is another way to compress the air in the bottle. By deducing its volume, the air exerts a greater pressure, causing the balloon to inflate. Water is also forced out of the hole.
This experiment serves as a good validation of Boyle’s Law, which states that as volume of gas decreases, its pressure increases, and vice versa. In other words the volume and pressure of a gas are inversely proportional.