its about science and machines

3. Lever
 It is a long rod that can be used to cut things,
move heavy objects, or open tins.
 for example :hammer, bottle-opener, a pair
of Scissors etc.

4.  A pulley is made up of a grooved wheel and a
rope. It is used to lift loads.
Machines such as cranes and sailboats make
use of pulleys.

5. Wheel and Axle
Wheel and axle is made up of a wheel through
which a rod is called axle passes. Such a
combination helps to move objects or change
their direction.
 Machines such as cars, roller skates and door
knobs make use of wheel and axle.

6. Inclined Plane
Inclined plane is used to lift heavy loads to a
height easily. An inclined plane makes
movement easier.
Some examples are ramp , slanted road , path
up a hill , slide etc.

7. WEDGE
A wedge is a simple machine used to push two
objects apart.
A wedge is made up of two inclined planes .
These planes meet and form a sharp edge. This edge
can spilt things apart.
Some examples are knives, axes, forks, nail ,etc.

8. Screw
A screw has ridges and is not smooth like a
nail .
Screws are also used to hold objects together.
They are used in key rings , bottle caps ,
fountain pen caps, etc.

9. Whenever you pick up anything heavy, your
elbow acts as the fulcrum of the lever, and
your arm bone acts as the lever itself.
 Natural body levers first developed
in fish around 440 million years ago.
 people used the lever in some form, for
moving heavy stones or as digging sticks for
land cultivation.

11. Questions

12. Fill in the blanks.
----------------- is a wheel and axle.
 A well is a --------------.
A ---------------- is made up of a grooved
wheel and a rope.
Ramp is a example of ---------------
Roller skates are example of ---------------
Wheel barrow is an example of ------------