Re: How do fireworks work ?

Dear Doug,


That's great that a young guy like you knows about  different elements 
making the different colors, WOW!
To answer your question about how the fireworks are made, here goes.
Fireworks are made with black powder, or what used to be known as 
gunpowder.  Gunpowder, as you know explodes; but only if it is put into a 
small space and packed very tightly.  In the case of a firecracker, and the 
shells that explode in the sky on the fourth of July, the gunpowder is 
packed very tightly.  The rockets that shoot the shells into the air use 
gunpowder as well, but one end is not packed tightly.  This allows the 
burning hot gases that are formed when the gunpowder burns to have a place 
to get out.  This is usually at the bottom.  The force that is created (its 
called thrust) moves out of the bottom, downward.  The reactant force in 
the opposite direction (See Issac Newton's Laws of Motion) causes to rocket 
to go upward.  

Back to the gunpowder.  Gunpowder does not explode, it only burns real 
fast.  Because it burns instead of exploding, it can be used to propel the 
rocket, and then packed differently to make it explode in the shell in the 
sky.