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K-Zone reader Jeff asked Dr. Rob Bell, presenter of Scope on Channel Ten this cool science question:


Question: Dear Dr. Rob: Why do flames sometimes come from the exhaust pipes of race cars? - Jeff, 12, NSW

Answer: Nice question Jeff! It might look like something out of a cartoon, but when flames shoot out the exhaust pipe, this is known as a backfire.

This can actually happen in any car, but happens more often in racing cars. When an engine works normally fuel is explosively burnt up and the gases produced are sent out the exhaust pipe. When a backfire happens some extra fuel remains unburnt, and exits the engine to the exhaust pipe as a gas.

Once there is enough oxygen again, and heat the extra fuel can burn off.  This usually this happens at the end of the exhaust pipe, shooting some flames out and often also making a small exploding noise!

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Scope airs Thursdays at 4pm on TEN.