Science project idea on how wheels are used in doing work.
Wheels Doing Work Science Project Idea
How wheels are used in doing work. Wheels are so commonly used in machines that when most of us think of machines and machinery, we also think of wheels. Like the lever, they may be used to gain force at the expense of distance or speed, or may be used to obtain speed or distance at the expense of force, or may be used to change the direction of the action of a force as in the beveled cogwheels used in transmitting the power of the crank shaft to the inner axle which turns the wheels of an automobile. The Windlass 
One of the most easily understood examples of the action of the wheel and axle is the case of the windlass which is used to draw water from a well, raise the anchor of a ship, or move buildings. Most of us have seen the delivery man on a coal wagon raising the bed of the wagon containing several tons of coal by turning a crank at the side of it. It does not seem difficult, although he is raising a weight many times greater than he would be able to lift unaided. The reason for the use of the crank, which is really only a spoke of a large wheel, may be understood by considering it as a lever. Comparing this with a lever, what may be considered to be the fulcrum, what the power arm, and what the weight or resistance arm? Explain the advantage in the use of the windlass, and its modifications in pulling or lifting heavy weights. Explain the ease with which the grains of coffee are crushed by the hand coffee grinder, and with which meat is chopped by the kitchen meat chopper.
Cogwheels and Wheels Moved by Belts 
In machines much use is made of cogwheels. With these, as with other simple machines, power may be gained at the expense of speed, or speed may be gained at the expense of power. The high and low speeds of the automobile illustrate this fact very well. Along the level road the car runs in high gear; but as soon as it begins to climb a steep hill, the driver, by means of a lever at his side, shifts the gears so that a different cogwheel (a smaller one) engages the crank shaft. The machine now has greater power, but less speed. Most automobiles have three speeds; first, second, and third, and the force exerted by the machine is in inverse ratio to the speed. In bicycles and in some motor trucks, a chain is used to transfer the power exerted by the pedals upon the sprocket wheel to the axle of the rear drive wheel. In this case as in cases of cogwheels that are in contact or mesh directly, the greater the size of the sprocket wheel, the greater the speed the machine possesses, with, however, correspondingly less power to climb hills. 
Belts are very commonly used in factories to convey power to machines. By a graduated series of wheels, the speed and the force exerted by the machine may be regulated. A very simple example is seen in the foot power sewing machine. The heavy rim of the small wheel, because of its inertia (the tendency of a body to remain in the condition of rest or motion in which it is), makes the running of the machine much more even, just as does the flywheel on an automobile. Why is the belt wheel on an engine that runs a threshing machine large, while the belt wheel of the threshing machine itself is small? Belts are able to move the wheels because of friction between the belt and the wheel.
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