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Can you give more information on how you can set a one dollar bill on fire but it does not burn if you soak it first in a alcohol solution.
Question Date: 2002-04-08
Answer 1:

As you know, dollar bills are made out of paper. For something to burn, its temperature needs to reach a point known as its ignition temperature. If you soaked a dollar bill in a pure alcohol solution and then lit it, I am pretty sure that it would burn the dollar bill.

what happens if the alcohol is diluted in water.

I think the "classic" science demo is to mix a 50:50 solution of alcohol and water together, and then soak the bill in it. When you try to light it on fire, you should see a flame, but then it will eventually go out and the dollar is still fine (wet and warmer, but not burnt). The key to this is the ability of water to absorb a large amount of heat. When you ignite the alcohol/water-soaked bill, only the alcohol will burn. The water absorbs the released heat, and thus keeps the temperature of the water-bill relatively cool. Now, if there isn't enough water present, the burning alcohol could heat the water until the water evaporates, in which case the heat from the burning alcohol could then heat the bill and cause it to ignite.

If you can experiment with this, you could try mixing differing amounts of alcohol and water together to find out at what concentrations the bill (here I'd suggest just using paper!) will ignite. Additionally, you could also experiment with different types of alcohol as well.

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