1. MACHINES UNIT 3 MACHINES MOVE THE WORLD Marta Vidal Vidal
L8 L9 L10 L11

2. IS A/AN ….. A MACHINE?
CHEESE GRATER u
AXE
SEE-SAW/

3. Let’s bet! Is a/an………..a machine?
Write questions for all the objects and bet (from 1 to 5).
Question
Yes, it is a machine.
No, it isn’t a machine.
BET
LOSS
GAIN
1. Is a TV a machine? 5 2. 3. 4. 5. 6. 7. 8. 9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20. Are scissors a machine?
TOTAL:
Is a drier a machine?
Is a cheese grater a machine?
Is a computer a machine?
Is an apple a machine?
Is a screw nut a machine?
Is a tow truck a machine?
Is a book a machine?
Is a washing machine a machine?
Is a telephone a machine?
Is a corkscrew a machine?
Is an axe a machine?
Is a see-saw a machine?
Is a well a machine?
Is a slide a machine?
Is a radio a machine?
Is an artichoke a machine?
Is a police car a machine?
Is a dog a machine?
Grand total=

4. IT CAN WORK WITH MECHANICAL ENERGY
WHAT IS A MACHINE?
It is a device designed to make work easier.
IT CAN BE SIMPLE
IT CAN WORK WITH
WIND ENERGY
IT CAN BE COMPLEX
OR COMPOUND
IT CAN WORK WITH
ELECTRICITY
IT CAN WORK WITH MECHANICAL ENERGY
IT CAN WORK WITH
SUN ENERGY
IT CAN WORK WITH CHEMICAL ENERGY

5. WHAT IS WORK?
WORK is done when a FORCE moves something. If you use a PUSH or a PULL to move an object you are doing WORK.
PUSH
PULL
FORCE
OBJECT

6. When we do work we use energy.
Law of conservation of energy.
“Energy can neither be created (produced) nor destroyed by itself.
It can only be transformed.”

7. HANDS ON! EXERCISE 1 LEVER
CAN WE LIFT THIS PENCIL?
CAN WE LIFT
THIS CHAIR?
CAN WE LIFT
A CAR?

8. CAN BOB LIFT THIS BIG ROCK?
Let’s see !!

9. Bob needs a little help
He needs a long stick
and
a small rock

10. Let’s see !
A big rock
Bob
Long stick
Small rock

11. LOAD
A big rock
LOAD
Bob
EFFORT
Long stick
LEVER
Small rock
FULCRUM
Yes, Bob can lift the rock with the help of the stick and the small rock. A STICK + A SMALL ROCK= A SIMPLE MACHINE IT IS CALLED A LEVER
EFFORT
LEVER
FULCRUM

12. At an appropriate distance the big rock moves easily.
LOAD
EASY TO MOVE
EFFORT
LEVER
At an appropriate distance the big rock moves easily.
FULCRUM

13. At an inappropriate distance the big rock doesn’t move.
LOAD
DIFFICULT TO MOVE
EFFORT
LEVER
FULCRUM
At an inappropriate distance the big rock doesn’t move.

14. HANDS ON! LEVER Ask some questions about the experiment.
PROBLEM:
Can we do the same work with less effort?
How many rulers do we need?
We need two rulers: one long and one short.
What do we do with the rubber?
We use the rubber as a fulcrum for doing a lever.
What is the big book for?
We use the big book as a load.
Which ruler do we use first?
Start with the short ruler and then do the same process with the long ruler.
What are the small books for?
We use the small books as an effort.
What is the ruler for?
We use the ruler as a lever.

15. HANDS ON! LEVER MATERIALS
Write down the materials that you need to create the lever.
Long ruler
Short ruler
A rubber
A big book
Small books
A pencil

16. HANDS ON! LEVER
STEPS
1. Predict: What is the best position of the rubber (as a fulcrum) to lift the big book with less effort (less small books)?
Predict: Which is the best ruler for lift the big book with less effort?
2. Prepare all the materials.
3. Start with the short ruler.
4. Try different positions for the rubber (fulcrum).
5. What is the best position of the rubber (as a fulcrum) to lift the big book with less effort (less small books)?
6. Change the short ruler for the long ruler and repeat the process.
7. What is the best ruler to lift the big book with less effort?

17. What is the best position of the rubber (as a fulcrum) to lift the big book with less effort (less small books)?
Known as
Position number 1

18. What is the best ruler to lift the big book with less effort?
It is the long ruler because it multiplies the effort applied.

19. LEVER
EFFORT
SMALL BOOKS
LOAD
BIG BOOK
FULCRUM
RUBBER

20. “Give me a lever long enough; a fulcrum strong enough and I’ll move the world.”
Archimedes

21. LAW OF THE LEVER
“Magnitudes are in equilibrium at distances reciprocally proportional to their weights.”
Archimedes
Força, Equilibri, Valor i Seny!
Force, equilibrium, courage and wisdom!

22. LEVER
It’s a rigid object that is used with an appropriate fulcrum to multiply the effort applied on a load.
Fulcrum: a support on which a lever pivots.
Load: resistance force (weight and gravity).
Effort: force needed to move an object.

23. THERE ARE 3 KINDS OF LEVERS

24. Identify in the pictures: FULCRUM: green dot EFFORT: red arrow LOAD: blue arrow/dot        
BOTTLE OPENER

25. Simple machine: LEVER FIRST CLASS LEVER SECOND CLASS LEVER
THIRD CLASS LEVER
NUTCRAKER
TWEEZERS
PLIERS
SEE-SAW
WHEELBARROW
SHEARING SCISSORS
SCISSORS
BOTTLE OPENER
TONGS

26. Other simple machines

27. INCLINED PLANE
It is an inclined surface used to raise an object. It decreases the effort.

28. WHEEL AND AXLE
It is a wheel with a rod, called and axle, through its centre: both parts move together.

29. SCREW
It is an inclined plane wrapped around a central shaft. The Rotational motion of the central shaft causes a linear upwards motion of the screw.

30. PULLEY
It is a wheel or set of wheels around which a single rope passes to move a load with a smaller effort.

31. WEDGE
Wedges are moving inclined planes which split or separate a load.

32. MACHINES SIMPLE MACHINES LEVER SCREW PULLEY WEDGE
HOW IT HELPS US WORK?
MACHINES
SIMPLE MACHINES
PLIERS
SCISSORS
TO LIFT OR TO MOVE LOADS
LEVER
THINGS MOVE UP OR DOWN IT
INCLINED PLANE
TO MOVE LOADS
WHEEL AND AXLE
TO HOLD THINGS TOGETHER OR TO LIFT
SCREW
TO MOVE THINGS UP, DOWN OR ACROSS
PULLEY
TO CUT OR SPREAD AN OBJECT APART
WEDGE

33. They are any combination of simple machines.
To know more about
Simple machines
Compound machines
They are any combination of simple machines.
Two levers
Two wedges
SCISSORS

34. LET’S FIND MACHINES IN OUR SCHOOL
PUPIL
ITS NAME
WE CAN USE IT TO…
WE CAN USE THE……. TO…
NAME OF THE SIMPLE MACHINE
 MARIA
JOSEP
1 SCISSORS
WE CAN USE THE SCISSORS TO CUT DIFFERENT THINGS LIKE PAPER. 
 2 LEVERS
2 WEDGES 2 3 4 5 6 7 8

35. A COMPOUND MACHINE

36. OUR SIMPLE LAWN-SPRINKLER
A ROCKING CHAIR ( A )
SQUEEZES A BULB ( B )
SPRAYING A SHIRT ( C )
THIS CAUSES IT TO SHRINK AND PULL THE STRING( D )
TIPPING THE SHELF (E)
THE HOMEMADE BISCUIT ( F )
FALLS HEAVILY INTO THE NET (G )
CAUSING THE ROD ( H )
TO RAISE A COVER ( I)
EXPOSING A MOUSE ( J )
A CAT CHASES THE MOUSE ( K )
THEREBY REVOLVING THE PLATFORM (L)
EACH TIME THE LAUGHING HYENA (M )
REVOLVES HE IS TICKED ON THE NOSE BY FEATHER BALL ( N )
CAUSING HIM TO LAUGH SO HARD HE CRIES – THE SPEED OF THE REVOLUTIONS SCATTERS TEARS OVER LAWN CAUSING THE GRASS TO GROW.

37. Some examples of compound machines
Some school projects
Different materials
Pythagoras switch
Advertisements
To look at the purpose To look at the materials To look at the idea Amazing !

38. Step-by-step process to build a compound machine
Phase
Step
What do you do?
Choose two partners 1
First
Second
Choose a theme for the machine
Third
Make a drawing/ sketch of a machine
Fourth
Write a list of materials and tools needed. 2
Fifth
Make the machine.
Sixth
Make two lists one for the verbs and one for the nouns.
Seventh
Use verbs to describe the action of the parts of the machine.
Order the different parts of the process.
Eighth
Write the steps of the movement of the different parts of the machine.
Ninth 3
Explain the machine function to other groups.
Tenth
Finally
Give your opinion as a group about the process of building the machine.