5.2.Simple machines

We use the word machine to describe a series of elements or parts that work together and use energy to perform a task and get a result.

A machine is a device created by the human being to facilitate work and reduce effort. It is characterized by the fact that it needs energy to function, transmits or transforms said energy and is capable of producing different effects (movement, sound, light, heat, etc.).

All the elements that we are going to study can be identified or classified by their principle of operation:

• Inclined plane: Reduces the effort used to raise an object in a vertical plane by increasing the distance travelled. Ramps, wedges and screws are flat inclined.

• Lever: Reduces effort by increasing the distance from a support point. Scissors, tweezers and balance are levers.

• Wheel: It is a circular mechanism capable of rotating around an axis transmitting or transforming the movement. Pulleys, gears and winches are wheels.

A simple scissors is a machine because they use energy created by our hands and transform it into a result: a cut of paper or fabric.

 All machines are composed of the following three components:

•  Driver element: power the machine

• Driven element: receives the force produced by the machine

• Transformer and/or transmitter element: transmits and/or converts the movement from the driver to the driver.

• Linear motion: The object follows a straight line path. For example, a pulley that raises a weight.

• Movement Rotation: Follows a path of circumference. For example, the pedal of a bicycle.

• Alternative movement: The object follows a line path, but forward and backward. For example, the cutting blade of a jigsaw.

• Oscillating motion: Follows a forward and reverse arc path. For example, a pendulum.