UNIT 14. MACHINES AND TECHNOLOGY (Natural Science, 4º E.P.)

14 MACHINES AND TECHNOLOGY

SIMPLE MACHINES

What is a machine?

A machine is a device which uses energy to exploit and direct a force.

The first machines were very simple and used human and animal energy.

Simple machines:

-          The lever: a rigid bar with a support which lifts objects.

-          The pulley: a wheel with a channel through which passes a rope to lift objects.

-          The wheel: a disc which spins around a central axle to push heavy objects.

-          The ramp or inclined plane: reduces the force to move a heavy object.

COMPLEX MACHINES

What is a complex machine?

A complex machine is the combination of many different simple machines.

At first, some complex machines used energy from human beings or animals. Then, complex machines used energy from the wind and water. Now, there are machines with motors that use fuel, electricity, etc.

MOTORS

What is a motor?

A motor is a machine capable of transforming energy into movement.

All motors work in a similar way:

-          They move using a source of energy.

-          They move by levers, wheels, pulleys, gears…

-          They move objects or carry out a task.

MACHINES OF THE PRESENT AND FUTURE

Automatic machines

An automatic machine is a machine which works and carries out its task by itself.

Robots are the most complicated automatic machines. They can receive and analyse information and then carry out a task.