Tuesday, July 28, 2009

How to fight fire in a wok?

I just saw this from the television. This caught my eye simply because it is a chemical thing?!

Problem: A wok of oil was heated and the surface of the oil caught fire.

Hypothesis 1: Use water.
Reason: Use water to fight fire, isn't it what we have always know?

Alright, this is wrong. If we use water, we die faster. Upon addition of water, the water will be evaporated due to the high temperature and become water vapour. Unfortunately, oil, being organic will then be attached to the water molecules and try to escape together (hot air rises), which helps the fire spread rapidly and cover more area. So whoever using water to fight fire with oil will be courting death.

Hypothesis 2: Use the wok cover.
Reason: It acts like a shield.

And yes, we should use the wok cover to cover the wok to prevent air (especially oxygen and hydrogen) from entering the wok, and hence combustion stopped. The effect can be enhanced by adding a wet blanket to cover up the wok, which helps in bringing down the temperature.

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