You have probably seen your parents vacuuming around the house. You may have used a vacuum, yourself, to clean up messes. While they may seem like mundane systems, they are actually pretty cool. Check out this vacuum chamber video!
Pierre wasn't so lucky. What happened? When the vacuum pump started to pump, the much of the air in the vacuum chamber was removed. By removing the air in a constant volume at a constant temperature, the pressure in the chamber decreases. Pierre the Peep is full of air. The marshmallow has pores that trap the air, but allow the air to escape from the Peep slowly. The air that is trapped in the peep has a higher pressure than the air in the rest of the chamber, making the peep expand. The air in the peep slowly escapes. Once air is again allowed in the chamber (the vacuum is broken), Pierre shrivels, since the air that made him nice and fluffy was pumped away.
You now may be thinking, "Who cares?" Scientists who use vacuum systems care. Certain experiments and processes can only be done at extremely low pressures (high or medium vacuum conditions). It takes time for gas trapped in materials to escape from them and, if the gas escapes to quickly, the materials can crack or break. Also, if materials keep on letting out air (or other materials), it can take impractical amounts of time to reach the low pressures required for the experiment.
I keep on talking about processes. What am I talking about? Watch this video demo showing of sputter deposition. We do processes like this in our laboratory. Sputtering is a process that can be used to lay down thin layers of material. We use sputtering to deposit some of the materials used in our solar cells.
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