Children's Science Encyclopedia Let us know How?

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How does a Steering Wheel make a car Turn?

Every automobile - car, bus or a truck is fitted with a steering wheel. The purpose of this steering wheel is to turn the automobile in the desired direction. In fact the driver uses the steering wheel to guide the automobile. Do you know how the steering wheel turns an automobile?

The steering wheel is connected to a long metal bar. It extends into a metal gear box in the front of the car. When one turns the steering wheel, the bar turns the gear. In many cars the gear is 'worm gear'. This worm gear turns another gear which is connected to a lever. The lever is connected to two rods. One rod is attached to the left front wheel, and the other to the right front wheel. So when the steering wheel is turned, the gear moves the lever. The rods attached to the lever make the car's front wheels turn left or right. This type of steering has a disadvantage: it needs higher steering ratios.

To make steering easy for the driver, without using higher steering ratios, power steering devices were introduced in the early 1930s. Most of the modern power steering systems consist of hydraulic boosts applied to either the steering linkage or the steering gear. Rotation of the steering wheel activates a valve that directs Oil, pressurized by a pump driven by the engine, to act on a piston. The hydraulic boost acts only while the steering wheel is moving.

AMAZING FACT: The carbon and hydrogen in oil can be made to join up in different ways to make more than half a million things. One of these things is petrol which is the most common fuel used to power our cars.

This books contains many more interesting facts about science and technology.