MACHINES- We need machines.- Simple machines.- Complex machines.- How a complex machine works.- The Science fair.

We need machines.

• A machine issomething we use to make work easier. We classifymachines as simple or complex.

• Simple machines have few or no moving parts. Allmachines use energy.

Simple machines…

• A lever: is a rigid bar with a support called a fulcrum.

Fulcrum

Simple machines

• A screw: is a type of inclined plane.

Simple machines

• An inclined plane: is a slanting surface that connects a lowlevel with a high level.

Simple machines

• A pulley: uses a wheel and a rope to lift or lower an object.

Simple machines

• A wheel: is a circular object that turns around an axle.

Simple machines

• A wedge: is an object with at least one slanting edge.

Complex machines

• They are made up of a number of simple machines workingtogether.

• Complex machines need energy: people, electricity or fuel.

• Examples of complex machines: Electrical appliances, forms of transport, robots.

• Machines are improving. They are getting quicker, efficientand safer to use.

Complex machines

HOW A COMPLEX MACHINE WORKS.

• A bicycle needs our kinetic energy to work.

• The handlebars are levers.

• The pedals are levers.

• The gears are pulleys…

Bicycles…

• The first bicycle was made of wood and no pedals, then thebicycle with pedals was invented, it was very uncomfortable.

• Next, a bicycle with a very big front wheel, and made of metal, very dangerous.

• After this, both wheels were the same size but still made of rubber.

• Finally, first bicycle with air in its tyres. Much safer.

Bicycles…

THE END…