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.