Science Notes: Bubbles

Wild Thing's bath time lately is almost entirely devoted to experiments with air pressure. He doesn't know that's what it's called--not yet!--but his favorite pastime is to hold a sippy cup under the water and watch the bubbles come out. "They're filled with air!" he says, quite pleased with himself. He pulls the lid of the cup off. "Where did all the air go?" he asks with a sly grin.