Editing Crush The Can (section)

== Why This Works ==

Pressure is when a force is applied over an area. Air pressure refers to the force that the air around us is constantly applying on us. We don't notice how strong air pressure really is, since our bodies push back and we stay un-smashed. But, we can see the effects by using this can.

When we heated the water in the can, we made it boil, and start to evaporate. Liquids take the shape of the container they are in, while gases take up all of the space within a container that they can. The steam caused the rest of the air to leave the can, leaving steam and boiling water in the can. The walls of the can could push back while it had gas (steam) inside to push against the gas (air) outside. When the can was flipped into the water, the steam inside of it condensed back to a liquid. This left a lot of empty space in the can, which we call a ''vacuum''.  Since we had no gas left inside the can, the gas outside could then exert a lot of pressure on the can and crush it!