Object: a pencil and a diamond ring

Good morning, boys and girls. How many of you own a pencil? Pencils are very handy things to have, aren't they? Are pencils very expensive? No, they are very cheap. They don't cost a lot of money at all. Now what about this diamond ring here. Do you think it's very expensive? Yes, it is. It cost a lot of money. Would you be surprised if I told you that pencil lead and diamonds are made of the same stuff? It's true. Pencil lead is made up of something called carbon. Obviously, pencil lead is made from very soft carbon, otherwise you wouldn't be able to write with it.

Diamonds are also made from carbon. But a diamond is one of the hardest things on earth. What makes the difference between a penc…