How come a shook up beer does not foam when quarter is pressed to the bottom of can?

When you shake up a can of beer, you create bubbles of carbon dioxide gas. These bubbles rise to the surface and create foam. When you press a quarter to the bottom of the can, you create a pressure difference between the top and bottom of the can. This pressure difference causes the bubbles to collapse and the foam to disappear.

The reason this works is because of the way that bubbles form. Bubbles are created when there is a difference in pressure between two areas. The greater the difference in pressure, the smaller the bubbles will be. When you press a quarter to the bottom of the can, you create a small area of high pressure at the bottom of the can. This high pressure causes the bubbles to collapse and the foam to disappear.

This trick works best with cans of beer that have been shaken up vigorously. If the beer is not shaken up enough, there will not be enough bubbles to create foam. The trick also works best with cold cans of beer. When beer is cold, the carbon dioxide gas is less soluble in the beer. This means that there will be more gas bubbles in the beer and the foam will be more voluminous.

So, if you want to impress your friends with your science knowledge, the next time you open a can of beer, shake it up vigorously and then press a quarter to the bottom of the can. The foam will disappear and you will be left with a perfectly smooth glass of beer.