# Simple Machines

## Levers

A lever is one of the six simple machines. It contains two parts: The handle and the fulcrum.

On the handle, there is a resistance (effort) and an applied (load) force. There are three types of levers: 1st class (top), 2nd class (middle), and 3rd class (bottom). An example of a lever (1st class, hopefully) would be a seesaw. The fulcrum is the stand in the middle and the handle is the bar you sit on.

## Pulleys

A pulley is another simple machine. The pulley contains: wheel(s), axle(s), and a rope. Pulleys are commonly used to lift heavy objects. Pulleys make work easier by increasing the distance between you and the weight, using a longer rope and more pulleys. An example of this could be operating an old elevator or simply lifting a heavy object. There are three types of pulleys: 1) fixed pulley (far left), movable pulley (middle), and block and tackle (far right).

## Wheel & Axle

The wheel & axle contains two parts. Can you guess which? I know, it's a hard question. Who would've thought that a wheel and axle contains a wheel and axle? Anyways, an example of a wheel and axle would be a screwdriver, in the sense that the handle is the wheel and the actual driver is the axle. Wheel and axles don't have a variety like levers and pulleys, but they cover a lot of ground; things you'd never even think of, like the wheels on a car, are wheel and axles. This machine makes work easier by increasing distance (you keep turning the wheel instead of going straight down), but decreasing the force needed. When you increase a wheel and axle's wheel (radius) and/ or decrease the size of the axle, the work gets even easier.

## Screw

A screw contains threads (those are the little grooves in a screw) and the head (the top, flat part of a screw). Screws are most commonly seen as an accomplice of the wheel and axle. The screw changes the direction of the screwdriver's force; it turns the circular motion into a straight-forward motion. However, this isn't always the case. If you're driving up a mountain, you go around the mountain several times while gradually going up. The road is a screw in this situation. It changes the direction of the car's force, making the work easier.

## Inclined Plane

An inclined plane is very, very simple. An inclined plane is just a flat slab of wood, metal, etc. that is angled to create a slope. Inclined planes help when you need to lift something up. Instead of lifting the object all at once, you can divide the the force needed and multiply the distance. An example of an inclined plane is a skating ramp or a wheelchair ramp. Instead of lifting the bike, you can ride it up the ramp; the only problem is there's more distance to go.

## Wedge

Also wedge, in a way, is a compound machine, which will be explained later. It is made up of two inclined planes. These two inclined planes are formed to create a triangle shape: one side is thick, the other is thin with a point. Wedges are commonly used to separate two items, or to cut an item into two pieces. An example of this could be a doorstop or a knife. The knife can cut, or separate an apple. Personally, I'm very glad we have wedges like knives. Could you imagine having to break am apple in half with your bare hands (if you weren't highly skilled in karate or something)? Me neither.
Dana's Six Simple Machines.wmv

## Compound Machines

The video above is a great example of a compound machine. A compound machine is simply a combination of two or more simple machines. Am example would be a bike, which is filled with several wheel and axles, levers, pulleys, inclined planes, screws and wedges. Another example is this very high-tech balloon popper. Now, you'd think compound machines are way better than simple machines, but there's a bad side to everything, well, everything except Batman. Batman is awesome. Anyway, that dark side is friction. When there's more machines, there's more friction, leading to a decrease in mechanical effiency. But, we'll just have to say, "oh well" and be lazy with our compound machines :)