Roman candles are a common kind of fireworks. They are made in this way: the inside of a hollow tube is divided into several separate little rooms. In the center of each room there is a hollow ball made of powder that will burn. The powder has gum and shellac mixed with it to hold it in shape. It has chemicals mixed with it to give it a pretty color when it burns. Packed around the ball there is loose powder. When the loose powder is set on fire, it explodes and shoots the ball out of the tube of the Roman candle. The powder in first one room and then another explodes. So one ball after another comes out. The balls themselves burn after they have been shot up into the air.
There are fireworks of many other kinds. But they are all made of the same kinds of chemicals and other materials.
Fireworks are dangerous. Most American cities now have laws that keep stores from selling them. Nowadays, instead of having fireworks in their back yards on the Fourth of July, people go to see a fireworks display at some place where there are men who can handle fireworks safely.
