This document discusses different materials and their properties. It explains that some materials are better suited for certain purposes than others, like glass being used for windows due to its transparency and bricks being used for houses due to their rigidity. It also covers magnetism, noting that only metal objects are magnetic, and properties of materials like bending, twisting, stretching and squashing. Finally, it distinguishes between natural materials made by nature and manufactured materials made by people.

1. UNIT 9

20. Some materials are
better for a
purpose than
others.

21.  Windows
are made
of glass because
glass is transparent.

22. 
Houses are made from
bricks because bricks
are rigid.

23. Magnetism

24. Some objects are
attracted to magnets.
 These objects are

magnetic.

25.  Only
objects made
from metal are
magnetic.

26. Bending
Twisting
Stretching
Squashing

27. Bend

31. Natural and
Manufactured
materials

32.  Natural
materials are
made by nature.

33.  Manufactured
materials are made by
people.

34.  Many
materials become
hard when cooled and
soft when heated.