Atoms!!
"All right. This is a picture of an atom. Can you show me which part is the - "
"Miss, what's an atom?"
(blink) "You haven't done atoms? No? Okay... atoms are what all matter is made of. They're like the building blocks that everything is made from. You're made of atoms. I'm made of atoms. The air is made of atoms. There are lots of different kinds of atoms, have a look at this periodic table - "
(peering at his hand) "I can't see any."
"They're very, very tiny. Microscopic. Things don't get much smaller."
"But what if you cut one in half?"
(rashly) "There'd be a huge explosion."
"What?!"
"Um... atoms are held together by powerful forces. If you split one it releases lots of energy. That's where nuclear power comes from. But it's very hard to split them in the first place."
(he turns pale, eyes darting around) "So there might be some atoms in this room?"
"Yes, there's lots - everything is made of atoms."
"Do I have atoms in my eyes?"
"Yeah. Your eyes are made of atoms. Everything is made of atoms."
"So I might have atoms on me right now?" (He's rubbing his arms, to wipe the pesky things off)
"Well, because everything is made of atoms, yes, you do."
"Isn't that dangerous?"
(struggling to keep straight face) "No, it isn't. Don't worry."
"But what if I just did this - " (he pinches his fingers together) " - and split one by accident?"
"Really. Don't worry. It takes huge amounts of energy to split the atom. It's never going to happen."
"But if it did, miss, I'd be in the newspaper, yeah?"
"Miss, what's an atom?"
(blink) "You haven't done atoms? No? Okay... atoms are what all matter is made of. They're like the building blocks that everything is made from. You're made of atoms. I'm made of atoms. The air is made of atoms. There are lots of different kinds of atoms, have a look at this periodic table - "
(peering at his hand) "I can't see any."
"They're very, very tiny. Microscopic. Things don't get much smaller."
"But what if you cut one in half?"
(rashly) "There'd be a huge explosion."
"What?!"
"Um... atoms are held together by powerful forces. If you split one it releases lots of energy. That's where nuclear power comes from. But it's very hard to split them in the first place."
(he turns pale, eyes darting around) "So there might be some atoms in this room?"
"Yes, there's lots - everything is made of atoms."
"Do I have atoms in my eyes?"
"Yeah. Your eyes are made of atoms. Everything is made of atoms."
"So I might have atoms on me right now?" (He's rubbing his arms, to wipe the pesky things off)
"Well, because everything is made of atoms, yes, you do."
"Isn't that dangerous?"
(struggling to keep straight face) "No, it isn't. Don't worry."
"But what if I just did this - " (he pinches his fingers together) " - and split one by accident?"
"Really. Don't worry. It takes huge amounts of energy to split the atom. It's never going to happen."
"But if it did, miss, I'd be in the newspaper, yeah?"