• Levers can make it easier for people to lift heavy objects or open things.

• The object being moved by a simple machine such as a lever is called a load.

• You would use less energy using a lever than if you simply tried to lift a rock.

• A wheelbarrow and seesaw are examples of levers.

• There are two types of pulleys a movable pulley and a fixed pulley.

• A single fixed pulley makes work easier by changing the direction of the effort force.

• When pulleys are used they can decrease the effort force needed to lift a load.

• A wedge changes a downward or forward force into a sideways force.

• A wedge is two inclined planes back to back.

• The blade of an ax is a wedge with a sharp edge.

• A wedge is a moving inclined plane.

• Movers use inclined planes to slide heavy objects in and out of their trucks.

• Inclined planes are also used to make it easier for handicapped people to get around.

• An inclined plane is a simple machine that only has one part.

• A screw is an inclined plane twisted into a spiral.

• When a screw is turned,

It moves forward.• You have to keep turning

a screw for it to move a short distance.

• You need only a small effort force to turn a screw.

• When you turn a doorknob, you are using a wheel and axle.

• A Ferris wheel is a wheel and axle.

• The wheel and axle has 2 parts, a wheel and the bar that passes through the center of the wheel.

• A screwdriver is a wheel and axle.