Mum signed me and CJ up to an science education web-site where for two years you can watch experiment videos on the computer and they add a new experiment to the site every week. Today I found out how sparklers worked and how to make sparks with iron filings and a candle.
How They Get the Sparks in a Sparkler
Most people have seen the type of fireworks known as sparklers. In fact, in many places they are about the only kind of fireworks that are legal. They consist of a thin wire about 10 inches long, with about half of the wire covered with a grey mixture. When you hold the base and light the other end, it burns and throws off bright sparks. Here, we will find out where those sparks come from.
You will need:
- a steel file
- a large nail or a piece of iron pipe
- a piece of white paper
- a flame (This can be a propane torch, the burner on your stove, or even a candle)
Hold the nail over a piece of white paper and begin to rub the file firmly against it. Soon, you should notice a fine, grey powder on the paper. This is iron that is being ground up by the file. Keep filing until you have a small pile of this powdered iron.
Light your flame. Now, carefully pick up some of the powered iron and sprinkle it carefully into the flame. Sparks! But wait a minute! Metal doesn't burn, does it?
Under normal circumstance, iron does not burn. If you hold a nail into a flame, it will not burn. It may get hot, and if it gets hot enough, it may even melt, but it does not catch fire. In order for iron to burn, it must be VERY hot and it must have quite a lot of oxygen. Both problems can be solved by making the pieces of iron very small.
Imagine trying to heat a large iron bar. It would take quite a while for the entire bar to get hot. Now, imagine using the same amount of heat on the nail. Since there is a lot less metal, it takes a lot less time for it to heat up. The smaller the piece, the faster it heats up. By powdering the iron, we allow it to heat up very quickly.
Powdering the iron also allows much more oxygen to reach the iron. Imagine heating the nail. Only its surface is exposed to oxygen, while most of the iron is on the inside, away from the oxygen. Now, if we powder the nail, much more of the iron is exposed to oxygen. This combination of quick heating and extra oxygen allows the iron to burn, producing bright yellow sparks. Powdered iron is one of the ingredients in the grey mixture on your sparkler.
When I do any more experiments from the site I will post about them.
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Posted by Anonymous 
Jan. 11, 2009 - Untitled Comment
My mom teaches science and has done a few experiments with fire--but nothing as exciting as this!
Thanks for sharing!
Blessings~
Renee