Friction heats things up

The Petersen Automotive Museum's new Cruisin' Classroom is available to schools upon request.
Courtesy Petersen Automotive Museum

Rub your hands together. The pressure and heat you create is called friction. Friction is the measure of the force that two objects or surfaces create when dragged against each other. Friction is created when you pull a box across a floor or when your bicycle tires move against the pavement.

Today, without friction, our cars would not be able to stop. Friction is created inside a car's wheels between the metal brake pads and the metal brake discs. The pads and discs are squeezed together under pressure. This pressure creates friction, which slows the wheels and stops the car.

The harder pressure is applied--like when you jam on the brakes on a bicycle or spin the tires in a quick takeoff--the more friction (and heat) is created. That's why some racing cars "smoke" their tires when they take off quickly. They create huge amounts of friction and heat when their large tires exert enormous pressure on the racetrack surface.

But friction is not always desirable. Auto engineers try to eliminate friction in many areas to reduce wear and tear. The engine, the door locks, even the windshield wipers will operate longer and better if the amount of friction between parts is reduced. Car designers even try to minimize the friction of the outside air flowing over a car's body by creating sleeker, lower designs that move more easily through the air.

You can learn more about this topic and more from the Petersen Automotive Museum's new Cruisin' Classroom, delivered to school campuses in a 1934 Ford panel truck. Teachers are invited to contact the museum at (323) 964-6347 for information on available dates and curriculums.

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