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Speaker 1: Welcome to brain Stuff from how stuff works dot com

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Speaker 1: where smart Happens. Hi. I'm Marshall Brain with today's question

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Speaker 1: why is it so hard to start some cars in

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Speaker 1: the winter? The whole starting your car and cold weather

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Speaker 1: thing could be a big problem for people who live

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Speaker 1: up north, and especially for people who live in really

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Speaker 1: cold places like Alaska. There are three reasons why cars

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Speaker 1: are hard to start when it's cold. First reason is

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Speaker 1: that gasoline, like any other liquid, evaporates less when it's cold.

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Speaker 1: You've seen this. If you pour water on a hot sidewalk,

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Speaker 1: it will evaporate a lot faster than it will from

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Speaker 1: a cooler place like a shady sidewalk. When it gets

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Speaker 1: really cold, gasoline evaporates slowly, so it's harder to burn it.

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Speaker 1: Sometimes you'll see people spray ether into their engines and

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Speaker 1: cold weather to help start them. Ether evaporates better than

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Speaker 1: gasoline and cold weather reason too. Oil gets a lot

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Speaker 1: thick or in cold weather. You probably know that cold pancakes,

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Speaker 1: syrup or cold honey from the refrigerator is a lot

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Speaker 1: thicker than hot syrup or honey. Oil does the same thing,

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Speaker 1: So when you try to start a cold engine, the

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Speaker 1: engine has to push around the cold, gooey oil, and

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Speaker 1: that makes it harder for the engine to spin. In

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Speaker 1: really cold places, people use synthetic motor oils because these

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Speaker 1: oils stay liquid in cold temperatures. Reason three has to

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Speaker 1: do with batteries. Batteries have problems in cold weather because

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Speaker 1: a battery is a can full of chemicals that produce electrons.

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Speaker 1: The chemical reactions inside batteries take place more slowly when

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Speaker 1: the battery is cold, so the battery produces fewer electrons.

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Speaker 1: The starter motor therefore has less energy to work with

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Speaker 1: when it tries to start the engine, and this causes

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Speaker 1: the engine to crank slowly in cold weather. All three

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Speaker 1: of these problems can make it impossible to start an

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Speaker 1: engine in really cold weather. People either keep their cars

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Speaker 1: in heated garages or use block heaters to get around

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Speaker 1: these problems. A block heater is a little electric heater

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Speaker 1: that you plug into the wall to keep the engine warm.

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Speaker 1: Do you have any ideas or suggestions for this podcast?

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Speaker 1: If so, please send me an email at podcast at

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Speaker 1: how stuff works dot com. For more on this and

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Speaker 1: thousands of other topics, go to how stuff works dot com.