Carson Greene
G Block Pressure Vs. Volume Essay Over the past few weeks, we have been studying the relationship between pressure and volume in a gas. We have used many demos which display the inverse relationship between pressure and volume. An inverse relationship means that as one of them (pressure or volume) increases, the other one decreases, and vice versa. When the volume increases, the pressure decreases and when the volume decreases, the pressure increases. Pressure is the force created by the number of collisions of molecules in a certain volume. A force is a push or a pull. Volume is the amount of
3­dimensional space in an enclosed object or shape. The relationship between pressure and volume can also be known as Boyle’s law, and we see this in everyday life. For example, when your ears start to pop as you get deeper in water, this is due to the imbalance of air pressure inside and outside of your ear drums. As you go from an area of high pressure to low pressure your ears are not ready for the change so they pop.
These are some terms that you will need to know in order to grasp the concept of pressure vs. volume in a gas.
In the first take home experiment you had to tie the center of a paper clip to the end of some string and thread the string through the opening in a CD so that you could lift the disc, then you make a small hole in newspaper and pull up fastly on the string

and see what happens. My prediction was that the CD would end up ripping right through the newspaper, but I was wrong. When I pulled the string the paper crumbled up to the center of the disc. This happened because when you pull the string it creates an air bubble, increasing the volume, and decreasing the pressure due to the inverse relationship. The end result of low pressure in a high volume meant that the only place for the paper to go was to the center of the disc.
In the second take home experiment, one that most of us have probably seen before, you had to fill a straw with water and then put our finger on the top of the straw, and then take your finger off the straw and observe what happened. My prediction was that the water would stay in the straw after a couple of drops came out of the end. My prediction for the second part of the experiment was that the water would fall back into the container once you lifted your finger off of the end. Both of my predictions ended up being right and the reasons what happened were all due to pressure and volume. For the first one, when the couple of drops came out, the volume decreased and my finger created a seal of high pressure which kept a little air and the water in the straw. When I took my finger off the end, the exact opposite occurred. The volume increased and the pressure decreased leading to gravity pulling the water back down to the container.
The third take home experiment was where you had to slightly overfill a glass of water and then put a file card over the top, then tilt the glass over and see what happens to the file card. Then you had to repeat the experiment but then next time with a half glass of water. I predicted that the notecard would stay stuck for the full