John: Balloon, fly away!
Roy: haha John. The balloon won’t fly away like that.
John: huh? The balloons flew away with a house in cartoon.
Roy: Those are probably filled up with helium gas. You are exhaling carbon dioxide.
It is heavier than oxygen, so it will not fly.
John: Oh! So, is helium lighter than oxygen?
Roy: That’s right!
John: Oh, I see. I thought the balloons will always fly in the sky!
Roy: I’m fully soaked!
John: Roy, Is it raining on the moon?
Roy: The moon has no air and water, so it never rains.
John: Aha! And everything in space floats. So will my balloon be floating in the space too?
Roy: There is air that you blew in, and the moon is in a vacuum state. What will happen?
John: Well? Will it shrink?
Roy: No, think more
John: Hm… BOOM?
Roy: That’s right! BOOM! There is a difference in pressure between outside and inside the balloon, so the balloon gets bigger to equalize the pressure outside. Later it will explode!
John: Oh my goodness! My balloon!
Roy: A human trying to wear a spacesuit has a similar reason too. Astronauts wear a spacesuit to protect their body!
John: Oh, I didn’t know that, I thought astronauts in spacesuits will trying to be look nice.
Roy: John. Didn’t you say you want to be an astronaut?
John: That’s right! I want to be an astronaut, not a scientist. Yes! Science is always mysterious! It’s so fun!
Roy: Alright. I think going to our next class is what we have to do right now.
John: Oh no! It’s time already! Let’s move on!