Machines

A machine is any tool or device that enables us to do work easily, quickly and conveniently.
A simple machine is a tool that allows us to use less force to do work. There are seven types of simple machines.

 
1.  Inclined plane
An inclined plane makes the job of moving loads from the lower to higher area or vice versa easier. For instance, pushing a heavy box to  a higher area needs less effort than carry it up. 
    










2.  Screw
A screw has ridges called thread, cut around it in the form of a spiral and special kind of inclined plane. When a turning force is applied to the head of the screw, the spiral edge of the screw travels a longer distance. This implies that the force was applied over quite a long distance to make the screw moves forward at a very small distance.  




3.  Gear
Wheels with notches and cogs, cut around the edge is called gears. Each gear is fitted to another gear to transfer movement in a machine. A gear is also used to changed the direction and speed of a movement.












4.  Pulley
A pulley is made up of wheel with groove round a rim of the pulley which holds a rope. A rope or pulley does not increase the lifting force but it only changes the direction of force. The force of pulling is equal to the weight of the load.



5.  Lever
A lever is a rigid bar or rod or plank that can swing around a support to transmit and magnify a force which is used to lift a load. The support or point on which the lever turns is called fulcrum. The object that the lever lifts or moves is called load. The force that is exerted on the lever is called effort.











6.  Wedge
When one or two incline planes are put together, back to back, it forms a wedge. A wedge changes the direction of a force and increases the effort. For example, using a sharp knife to cut sweet potato. As the knife moved downwards it creates a strong sideways force that spilts it open. 











7.  Wheel and axle
Wheel is a cylindrical object or circular object that rotates about the axis of the cylinder. The axle is a rigid rod that goes throught the centre of the wheel and lies along the culinder axis. When the two are combined together, it is called a wheel and axle.











 Vocabulary


ENGLISH
BAHASA MELAYU
complex machine
mesin kompleks
daily chores
kerja harian
hand drill
gerudi tangan
Inclined plane
satah condong
lever
tuas
load
beban
pulley
takal
screw
skru
simple machine
mesin ringkas
thread
bebenang
wedge
baji
wheel and axle
roda dan gandar



Before ending this lesson, let' s do some tests.





TEST B - MACHINES

For each of the following complex machine, tick (√) the simple machines found in them.





No


Complex machine
Simple machines found in them
L = Lever
WA = Wheel and axle
IP= Inclined plane
P = Pulley
S = Screw
W = Wedge
G = Gears
L
     WA
IP
P
S
W

G

1
A pair of scissors







2
A bicycle







3
A manual can opener








4
A wheelbarrow







5
A lawn mover








6
A hand drill







7
A G-clamp







8
A hole puncher








9
A step ladder







10
A tower crane











Have a good try!



6 comments:

  1. Thank you for viewing, Jing Yee.
    I have put in some exercises for this topic, You might try to answer.

    ReplyDelete
  2. Here are the answers :
    1. √
    2. X
    3. √
    4. √
    5. X
    6. √
    7. X
    8. X
    9. √
    10. X
    How many correct answers do you get?

    ReplyDelete
  3. I have changed the true or false questions into another form of question as TEST A and added in TEST B. It is more challenging, try it!

    ReplyDelete
  4. I think the students should try out those simple machines, because this may help them alot in their daily lifes instead of playing the meaningless computer games or video games and watching those dramas that could mislead their thinking easily... =)

    ReplyDelete
  5. Koo, you are right, I agree with you.

    ReplyDelete