Simple Machines

Simple Machines
Simple Machines are basic mechanical devices for applying a force and doing work. More complex machines are made up of a bunch of simple machines. 

There are 6 basic types of simple machines: 

Lever 

The lever is made up of a straight rigid object like a board or a bar which pivots on a turning point called a fulcrum. Levers make work easier by using leverage which multiplies the force. When you use a lever, you move a smaller force a longer distance in order to lift a load a short distance. Examples of levers include a seesaw, pliers, crowbars, and tweezers. 

See the above pictures for examples of how a lever is used in a wheelbarrow and construction equipment. 

Wheel and axle 

The wheel and axle is another simple machine. It uses a wheel with a rod attached in the middle as an axle to help it to lift or move loads. In some cases this machine works like a lever to multiply force (like with a doorknob or a fishing reel). In other cases it is used to move objects easier such as with wheels on a bicycle. 

Pulley 

A pulley is a type of simple machine that uses a wheel with a groove in it and a rope. The rope fits into the groove and one end of the rope goes around the load. You pull on the other end. The pulley helps you to move the load or change direction of the force. 

Some examples of pulleys include cranes, flag poles, and window blinds. When multiple pulleys are used together it's called a block and tackle. Another use of the pulley is with a flat wheel and belts. These kinds of pulleys are often used in cars. 

Inclined plane 

An inclined plane is a flat surface with one end higher than the other. This allows for heavy objects to slide up to a higher point rather than be lifted. It is generally easier to slide something than to lift it. 

Examples of inclined planes include slides and ramps. 

Wedge 

If you put two inclined planes back to back, you get a wedge. A wedge is a simple machine used to push two objects apart. 

Examples of the wedge include knives, chisels, and axes. 

Screw 

A screw is a special kind of inclined plane. It's basically an inclined plane wrapped around a pole. Screws can be used to lift things or to hold them together. 

Examples of the screw simple machine include swivel chairs, jar lids, and, of course, screws. 

Fun Facts about Simple Machines

• Simple machines were first discovered and described by Greek philosopher Archimedes.
• The Egyptians likely used the inclined plane to help build the pyramids. Using ramps would have made getting the large stones to the top much easier.
• Galileo was the first to work out a working mathematical theory on how simple machines worked.
• Your bicycle makes use of nearly every kind of simple machine in order to make a more complex machine.
• The wheel and axle was an important invention in the history of mankind. It was first used around 5,000 years ago by the Sumerians.

Motion Glossary and Terms

Motion Glossary and Terms
Acceleration - Acceleration is the measurement of the change in an object's velocity. It is equal to the change in velocity over the change in time. Acceleration is a vector. 

Collision - A collision in physics occurs when any two objects bump into each other. 

Displacement - In physics, displacement refers to an object's overall change in position. It is a vector quantity. 

Energy - Energy is the ability to do work. The standard unit of measure for energy is the joule. 

First law of motion - The first law of motion states that any object in motion will continue to move in the same direction and speed unless external forces act on it. 

Force - Force is the measurement of a push or pull on an object. Force is a vector measured in newtons. 

Friction - Friction is the resistance of motion when one object rubs against another. It is a force and is measured in newtons. 

Gravity - Gravity is a force caused when the mass of physical bodies attract each other. On Earth gravity pulls at objects with an acceleration of 9.8 m/s². 

Impulse - An impulse is a change in momentum. 

Joule - The joule is the standard unit of measure for energy and work. 

Kinetic energy - Kinetic energy is the energy an object has due to its motion. It is a scalar quantity calculated using the formula KE = ½ * m * v², where m = mass and v = velocity. 

Mass - Mass is a measurement of how much matter is in an object. It is usually measured in kilograms. 

Momentum - Momentum is a measurement of mass in motion. Momentum is equal to the mass times the velocity of an object. It is a vector measured in newton-seconds. 

Newton - The newton is the standard unit of measure for force. 

Pascal - The pascal is the standard unit of measure for pressure. 

Potential energy - Potential energy is the energy stored by an object due to its state or position. It is measured in joules. 

Power - Power is a measurement of the rate at which energy is used. Power is calculated by dividing work over time. The standard unit for power is the watt. 

Pressure - Pressure is the force over a given area. Pressure is measured in pascals. 

Scalar - A scalar is a measurement that only measures the magnitude. Unlike a vector, a scalar does not have direction. 

Second law of motion - The second law of motion states that the greater the mass of an object, the more force it will take to accelerate the object. 

Simple machine - A simple machine is a basic mechanical device for applying a force and doing work. Some examples of simple machines include the lever, pulley, inclined plane, wedge, and screw.

Speed - Speed is the measurement of how fast on object moves relative to a reference point. It is a scalar quantity measured by distance over time. 

Third law of motion - The third law of motion states that for every action there is an equal and opposite reaction. 

Vector - A vector is a quantity that has both a magnitude and a direction. 

Velocity - Velocity is the rate of change in an object's position. Velocity is a vector quantity. The magnitude of velocity is the object's speed. 

Watt - The watt is the standard unit of measure for power. 

Weight - Weight is the force of gravity on an object. In physics, weight is measured in newtons. 

Work - Work occurs in physics when a force acts on an object to move it some distance. Work is equal to the force times the distance and is measured in joules.