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Hi guys! Let's do some revision of the unit Machines.

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In this unit, we have learned that machines in general help us every day to make work and life easier.

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As you already know, there are two types of machines.

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Simple machines and complex machines.

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Remember, simple machines are based on just one element.

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Did you know that there are six different kinds of simple machines?

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Let's see if you can name all of them.

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They are the lever, the screw, the inclined plane, the pulley, the wedge and the wheel and axle.

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Which one of those machines would you use to lift a very heavy sofa from the street

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and get it inside your sitting room through the balcony?

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Exactly, a pulley, which consists of a rope and a wheel.

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On the other hand, complex machines are formed by two or more simple machines, a wheelbarrow,

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A hairdryer or a computer are examples of complex machines.

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In this unit, we have also learned about inventors and inventions.

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Many people throughout history have invented machines.

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These machines have changed people's lives and made work easier.

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What was the name of that amazing mathematician that invented the screw and many war machines?

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Archimedes.

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There have been other inventions like the windscreen wiper by Mary Anderson in 1903.

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The windscreen wiper is nowadays a standard part of all cars.

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Moreover, the pedal bicycle was invented by Kirkpatrick Macmillan and the first power plane was designed, built and flew by the Wright brothers.

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We don't forget to mention Rube Goldberg Machines. We are both looking forward to seeing all your creations.

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Some of the ones we have received are great.

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We hope that you have learned a lot during this unit and that you've had a lot of fun.

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Bye-bye!