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force applied. The circular motion

helps to move things upward and

downward.

A screw holds things together for a

longer distance with a stronger grip.

We attach doors and windows of our

rooms to walls with screws. A screw is Screw Screw Jack
used to lower and raise things and to

hold objects together. Screw jack is also a simple machine which is used to lift up the

side of a car or bus while replacing its wheel or tyre.

Let’s Discuss

How are simple machines useful to us? Do they make our work easier or
difficult? Discuss about it in the class!

Aim: To show that a screw is an inclined plane.
Materials required: Piece of paper (10 cmx 10cm), scissors, pencil, crayon, tape.
Method: Take a square piece of white paper (10 cm × 10 cm) and cut it into two
triangles. Use a crayon to mark the longer edge and wrap the paper around a nail or a
pencil and fix the ends with a tape. The coloured edge of the paper looks like the
threads of a screw.

Wheel and Axle

A wheel and axle has two parts to it. They are the
wheel and the axle. The axle is a rod that goes through
the wheel. This lets the wheel turn. A wheel and axle
helps to move objects. The faster the axle is turned,
the faster the wheel spins. The idea of a wheel and axle
was created when past societies like the Egyptians and
Aztecs used round rocks under heavy objects to move
them. The two examples of wheel and axle are
rollerblades and gears in Clocks. Rollerblads are made up of many wheel and axels.
They are machines because they help people move faster. The hands of a clock move

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