SIMPLE MACHINES

 WHAT ARE THE SIMPLE MACHINES?

Simple machines make the work easier by reducing the effort needed. They usuallly have 1 or 2 parts.

TYPES

Levers (Palancas)

A lever is a rigid bar (barra rígida) with a pivot point (punto de apoyo), where the lever turns. 

The object we need to move is the load (carga) and the person using the lever applies a force, called the effort (esfuerzo).

Pulleys (Poleas)

A pulley has 3 parts: a wheel (rueda), an axle (eje) and a rope (cuerda). The axle passes through the centre of the wheel and the rope runs around the outside of the wheel. 

Pulleys make easier to lift (subir) or lower (bajar) heavy objects. Two or more pulleys together make it even easier.

Inclined plane (Plano inclinado o rampa)

An inclined plane is a ramp used to lift or lower objects and it only has 1 part. It increases the distance we move an object but reduces the effort needed. 

A screw (tornillo) is an inclined plane wrapped around a pole (entrelazado alrededor de un tubo). 

A wedge (cuña) has two inclined planes, like an axe (hacha)

SOUND ENERGY

 Why can you hear things?

When we make an object or substance vibrate, sound energy is produced.

What is sound energy?

Sound is the form of energy that allows us to hear things. It travels in waves and makes the air vibrate. 

These air vibrations travel in all directions and very fast through different materials, and finally enters our ears. 

Some curiosities

Unlike (al contrario que) light energy, sound can not travel through a vacuum (en el vacío del espacio), because there are nothing to transmit the vibration.

Machines and transport can produce sounds that are harmful to human and animal life. This is called noise pollution.