This week's science--Pop a Quarter

Pop a Quarter

Once again K2 and I did a science lesson on a  property of air. 
K2 took a clear, plastic shoe box, added about 3 inches of water and put it in the freezer the night before.  We used this icy container to keep our pop bottles and the air inside of them chilled.

We asked the children to choose a partner and gave each team a pop bottle (don't touch! we don't want to warm the air!), a quarter and a shared cup of water. 

• First dip a finger in the cup of water and wet the top of the pop bottle.

• Set the quarter on top to trap the air, being careful to keep it centered so no air can escape.

• Now carefully, you and your partner wrap your hands around the pop bottle and use your eagle eyes and ears  to monitor what the quarter does.

Warm air takes up more space than dense cold air, so the quarter will "pop" ever so slightly as the warm air seeks escape.  One website I found described this as burping which I'm sure would get the giggles going.  Another suggested slowly lowering the pop bottle into warm water to watch more vigorous quarter action.