2. •
A machine is something we use to make work easier. We can classify machines
as simple machines or complex machines
• Simple Machines: Have few or no moving parts.
Pliers
3. • There are six simple machines:
• 1) A pulley, uses a whell and a rope to lift or lower an object.
• 2) An inclined plane, move objects up or down.
4. • 3) A Srew, is a hold things together or lift objects
• 4) A Wheel, turn around an axle. We use it to lift or move objects
5. • 5) A Wedge, we use a wedge to cut objects.
• 6) A Lever is a rigid bar with fulcrum. We use it to lift or move objects.
6. • Complex Machines are made up of a number of simple machines
working together.
• Complex machines need energy. This energy can come from people,
electricity or fuel. We use complex machines every day,complex machines
are everywhere.
7. • Electrical appliances: Some examples are: Washing machines, cookers and
calculators in our schools.
• Which energy do they use? They use electrical energy. And some electrical
use energy from batteries.
• Forms of transport: Some examples are: Buses, cars, lorries and bicycles.
• Wich energy do they use?
• They use the fuel energy, but bike uses people energy. Some are electrical
energy.
8. • Robot at work:
• What do we use them for?
• They use robots to make mass-produced products, and they do jobs
dangerous for people.
• What are the advantages of robots?
• The advantages are that are more efficient and safer to use.
9. • A bicycle is a complex machine because it´s made up of some simple
machines working together. It needs kinetic energy.
– 1) Handlebars. They are levers that help us change direction.
– 2) Pedals. They are levers. They make the wheels turn around when we push them with
our feet.
– 3) Gears. They are pulleys that help us when we have to go up or down a hill.
– 4) Gear Controls. They are levers in the handlebars that are connected to the gears
through cables.
– 5) Brakes. They are levers that help us slow or stop the bike. They are in the wheel.
– 6) Brakes Levers. They are in the handlebars and are connected to the brakes through
cables.
11. • 1.- The first bicycles were made of wood. They had no pedals and used
their feet to walk at the same time.
• 2.- A bicycle with pedals was invented. This bicycle had metal tyres.
• 3.- A bicycle with a very big front wheel was invented. Its tyres were made
of solid rubber.
• 4.- Both wheels were the same size, but wheels were still made of solid
rubber.
• 5.- The first bicycle with air in its tyres was invented
