Machines

are devices that allow us to use less force

to make work easier and faster

Simple Machines

wheel and axle

levers

wedge

pulley

screw

gear

inclined plane

Complex Machines

made up of two or more

simple machines

Life Without Machines

Many tasks cannot be done easily.

Life will be tough and difficult

Everything have to be done by bare hands.

Designing Machines

Identify problems

Planning

Making the model

Wheel and Axle

well

screwdriver

steering wheel

windmill

The wheel and axle is made up of a large wheel

connected to a rod called an axle which rotates on the centre point of the wheel; to lifts or moves loads.

tap

ferris wheel

skateboard

rolling pin

sharpener

doorknob

Wedge

A wedge consist of one or two inclined

planes joined together to form a V shape or a

sharp edge.

a knife is used to cut a cube of butter

an axe used to splita wood into two

a chisel is used in woodworking

a zipper used to fastenor separate two objects

a doorstop that is wedged under a door to prevent it

from moving

a crowbar is used to lift heavy objects

Pulley

A fixed pulley is a pulley that does not

move. When the rope is pulled, the load is

pulled up. The pulling force is the same as the weight

of the load.

A movable pulley moves with the load. The force needed to pull a load is half the

weight of the load but have to pull

upwards.

Combined pulley system is a

combination of fixed and movable pulleys. It enables us to use less force to lift the

load.

A pulley is made from a wheel and a rope.

The rope fits into the groove on the wheel; to raise, lower or move a

load.

Gears

Gears are wheels that have 'teeth'. The teeth fit

together so that when one gear turns it also turns the other gear.

Sometimes the gears fit right together, and

sometimes they work together through a

chain or a belt.

a hand drill

wrist watch

an egg beater

Screw

an aluminium can with screw lid

nut and bolt

a spanner

bicycle tires have threads on the stem to

screw the cap on

Closer threads have longer

inclined plane, less force to move

the load.

A screw has a spiral inclined plane called

thread. Screws can be used to hold things together, lift heavy

loads or drill holes on objects.

a bulb

a G-clamp

a car jack

Far apart threads have shorter inclined plane, more force to move the load.

a corkscrew

a drill bit

Inclined Plane

escalators

An inclined plane is a sloping surface which

connects two other surfaces at different levels; to reduce the effort needed to raise

or lower an object over a vertical height.

a lorry ramp

stairs

a wheel chair ramp

a flyover

Complex Machine

wheelbarrow

lever wheel & axle

coconut shredder

wheel & axle screwwedge

paper cutter

lever wedge

wheel & axle gears screw wedge

hand drill

Produced by combining together two or more simple

machines to perform a certain task.

ais kachangmachine

screw wheel &

axle wedge

wheel & axle screw

G-clamp

wheel & axle gears

wrist watch

corkscrew

wheel & axle screw lever wedge

lever wedge

nails clipper

lever wheel & axle

gears

bicycle

lever wedge

scissors

Lever

Is a rigid bar that rests on a turning part.

Consist of 3 parts.

Fulcrum (F)

( the turning point )

Load (L)

( the object that is moved by the lever )

Effort (E)

( the force used to move the object )

The effort used to move the load depends on:

the position of the fulcrum

The closer the object (load) is to

the fulcrum, the easier it is to move the

load.

The further the effort is

from the fulcrum, the easier it is to

move the load.

the size of the lever

The longer the lever is, the lesser is

the effort needed to move the

load.

Uses of Levers

In lifting heavy loads with less

effort.

Moving things a greater distance.

Increasing the speed of an

object.