Danny,Jenny and Brian are in the lab.
Brian: Let's do an experiment.I fill a jar with water. I cover the top with a piece of cardboard and hold it there.Then I turn the jar upside down and take my hand off the cardboard.Can you guess what will happen?
Danny: I think the floor will get wet.We should do this experiment outside, Brian.
Jenny: I think the cardboard will hold the water.
Danny: I don't think so.
Jenny: You think the water will pour out,Danny.I think the water will stay in the jar.Let's test which theory is correct.
Brian: Good idea,Jenny.That's called the scientific method.
Jenny: I am so sure of my theory that Brian can do the experiment over your head and I know you won't get wet.
Danny: Well, let's try it!
Brian: Are you ready, Danny?
Danny: No! Wait!(He puts on a raincoat and sits down.) Now I think I'm ready.
Jenny: Brian,take your hand off the cardboard.
Danny: No!
(Danny closes his eyes tightly,and Brian takes his hand off the cardboard.The water stays in the jar.)
Jenny: See,Danny!
Danny: How is that possible?
Brian: The force of the air keeps the water in the jar.It is strong enough to hold the water.
Danny: Wow!
Brian: So what have we discovered?
Jenny: We have discovered that the air pressure helps the cardboard hold the water in the jar.
Brian: Right.What do you conclude,Danny?
Danny: I conclude that air is stronger than I thought.