3º NS Unit 6 – MACHINES AND INVENTIONS (Student´s Book and Activity Book SOLUTIONS)

HOMEWORK:

1. Check the solutions to the exercises you did last week from the books of N.S. (Student´s Book and Activity Book).

UNIT 6 Natural Science – MACHINES AND INVENTIONS

3º NS STUDENT´S BOOK (solutions)

PAGE 91

SOLUTIONS

1 Lorry, trolley, lever, cutter, camera, pulley, computer, etc.

2 Lorry, trolley, lifting jacks, etc.

3 Pupils' own answers, for example:

Simple machines have few or no moving parts (guillotine, ramp, chair).

A complex machine is made up of simple machines that work together (printing press, lorry, digital camera).

4 Pupils' own answers using ideas from the picture.

5 Scissors, phone, trolley, hammer, computer.

PAGE 92

SOLUTIONS

1 - c, d, b, a.

PAGES 94, 95

SOLUTIONS

1 - a.2; b.3; c. 1.

2 A simple machine is a machine that makes work easier, but having few or no moving parts. It needs the energy from the person using it to work. For example: screw, lever, etc.

3 Possible answers:

Wedges can be used to keep doors open and they are also used as the cutting edges in scissors. Tweezers and wheelbarrows work using levers and fulcrums.

A skateboard uses wheels and axles.

4 a. wheel and axle - b.lever - c.wedge

PAGE 96

SOLUTIONS

1 Cars, and any other examples of road vehicles.

2 Wind or human-powered vehicles and machines, etc.

3 Pupils' own answers.

PAGE 97

SOLUTIONS

1 1700; the steam train was invented 104 years later.

2 Burning coal or diesel.

3 It uses magnets to travel at 350 km per hour.

3º NS ACTIVITY BOOK (solutions)

PAGE 32

SOLUTIONS

1 – A machine is something you use to make work easier. – A simple machine has few or no moving parts. – A complex machine is made up of simple machines.

2 – inclined plane – wheel and axle – lever – wedge – pulley – screw.

3 – a. wheel and axle – b. inclined plane – c. wedge – d. pulley – e. screw – f. lever.

PAGE 33

SOLUTIONS

4 – a. wheel and axle – b. wedge – c. pulley – d. lever, screw – e. inclined plane – f. screw, lever.

5 – people – electricity – fuel – electricity – fuel – people.

PAGE 34

SOLUTIONS

6 – compass – telephone – wheel – lightbulb – internet.

7 – lightbulb (artificial light) – telephone (speaking to people in different places) – wheel (land transportation) – internet (world wide network of computers).

PAGE 36

SOLUTIONS

1 – Student’s own answers. OPEN answers.

PAGE 37

SOLUTIONS

1- b. complex – c. of a finger – d. levels