We use the wheel and axle in gears. Gears have teeth around the outer rim. When the teeth of two gears fit together and one gear turns, it will cause the other gear to turn, but in the opposite direction. When the gears are the same size and they have the same number of teeth, they both turn at the same speed. If one gear is larger than the other, however, the smaller gear will turn faster. We use gears to regulate speed and direction of motion in complex machines and to increase/decrease the force applied. Machines that use gears include clocks, bicycles, cars, eggbeaters and other small household appliances. A crank is the handle of a machine that is connected at right angles to an axle. It is used to transmit motion. On a bicycle, the pedal attached to the gears is a crank. Cranks are used for turning, for example, the spinning wheel, eggbeater, peppermill etc. f) A Pulley Pulleys are wheels with grooves around the rim. The pulley turns as a string moves over the wheel and a load is raised as the string is pulled. This is a fixed pulley which doesn't change position. A fixed pulley makes work easier by changing the direction of the applied force. With a fixed pulley, the force required to lift the load remains the same as lifting it by hand, but realize how much easier it is to raise a flag or sail from the ground, as opposed to climbing up the pole or mast. If a force needs to be applied around a corner, a pulley allows us to overcome friction. With a moveable pulley, both the load and the pulley move; the load moves in the same direction as the applied force. Moveable pulleys allow you to use less force to raise an object than if you used only your hands. The amount of force required depends on the number of supporting ropes. The greater the number of pulleys and supporting ropes, the smaller the force required.
We use the wheel and axle in gears. Gears have teeth around the outer rim. When the teeth of two gears fit together and one gear turns, it will cause the other gear to turn, but in the opposite direction. When the gears are the same size and they have the same number of teeth, they both turn at the same speed. If one gear is larger than the other, however, the smaller gear will turn faster. We use gears to regulate speed and direction of motion in complex machines and to increase/decrease the force applied. Machines that use gears include clocks, bicycles, cars, eggbeaters and other small household appliances. A crank is the handle of a machine that is connected at right angles to an axle. It is used to transmit motion. On a bicycle, the pedal attached to the gears is a crank. Cranks are used for turning, for example, the spinning wheel, eggbeater, peppermill etc. f) A Pulley Pulleys are wheels with grooves around the rim. The pulley turns as a string moves over the wheel and a load is raised as the string is pulled. This is a fixed pulley which doesn't change position. A fixed pulley makes work easier by changing the direction of the applied force. With a fixed pulley, the force required to lift the load remains the same as lifting it by hand, but realize how much easier it is to raise a flag or sail from the ground, as opposed to climbing up the pole or mast. If a force needs to be applied around a corner, a pulley allows us to overcome friction. With a moveable pulley, both the load and the pulley move; the load moves in the same direction as the applied force. Moveable pulleys allow you to use less force to raise an object than if you used only your hands. The amount of force required depends on the number of supporting ropes. The greater the number of pulleys and supporting ropes, the smaller the force required.
Integrated%20unit%20Simple%20machines%20senior%20classes.docx