Is Air There????!

To learn the wonderful subject of air pressure, I did a lab called Is Air There. This lab involved a cup, two rubber bands, and a plastic bag. I used this to measure where air pressure is and observe what affects it has on the plastic bag. Firstly, I had to set up the plastic bag over the mouth of the cup, tightly secured by rubber bands. Next, I had to attempt to push the bag into the cup, but I could not do so, because there was air pressure when I pushed on the bag, resisting me from pushing the bag into the cup. Next, I inserted the bag into the cup, and tightly secured the bag into the cup with the rubber bands. Then, I had to attempt to pull the bag out of the cup, but I could not! The reason is because the air pressure is now on the outside of the bag, so when I attempted to pull the bag, the air pressure resisted me to do so. As a response to the Thinking It Over, by using the plastic bag to cover the cup, the air pressure was inside, so I could not push the bag inside the cup. When I inserted the bag into the cup it was just the opposite, the air pressure was on the outside, so I could not pull the bag outside the cup. Also, the Thinking It Over asked what would happen to a balloon if it increased altitude. Well, the answer is that that air pressure, as the balloon increased altitude, it would be deflated from the increased air pressure. I found this lab to be very interesting, and education. This was a simple lab, but there was a whole lot of science to it.