Simple machines make it easier for people to perform tasks, such
as lifting or pulling, which would be difficult to do with muscle
strength alone. There are six types of simple machines: the wheel,
the screw, the lever, the pulley, the inclined plane, and the wedge.
These machines change a force into a bigger or smaller force, or
alter the direction in which a force acts. The most basic tools, such
as crowbars or spades, are simple machines.Machines
(^1) WHEEL (GEAR)
Gears are toothed wheels that mesh
and turn together, changing the
strength, speed, or direction of a
force. A force on the axle of a small
gear driving a large gear will lead
to a bigger turning force on the
axle of the large gear.
(^2) SCREW
The spiral thread on a screw
changes a turning force into a
much stronger up or down force.
The screw has to be turned many
times to create just a small up or
down movement.
(^3) LEVER
Most levers magnify the force
applied to them, making it easier to
move a load. A lever turns around a
fixed point called a pivot. The further
from the pivot the force is applied,
the easier it is to move the load.
The downward
motion of the
wedge splits the
tomato in two
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The second lever falls,
bringing the wedge
down onto the tomato
The turning motion of the
wheels is converted into
linear motion, moving the
cart up the slope
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