UNIT 8: MATERIALS AND MACHINES

UNIT 10: MATERIALS

1. MATERIALS:
  - Natural materials: are found in nature. Ex. wood, leather, cotton, wool and sand.
  - Man-made materials: are made by people. Ex. paper, glass or plastic

Paula! I need your notebook! Sorry:)

2. PROPERTIES OF MATERIALS:
   - Flexible: It doesn't break --> Leather
   - Strong: It can support a lot of weight and force --> Iron
   - Elastic: It can be stretched an it returns to its original shape --> Rubber

   - Light: It does no weigh much --> Aluminium

   - Transparent: Light can pass through it, and you can see through it --> Glass
   - Heat-resistant. It withstands high temperatures --> Steel
   - Waterproof: It doesn't let water pass through --> Plastic
   - Fragile: It breaks easily --> Glass

3. HOW WE USE MATERIALS:
    Some materials are very versatile, they have different uses due to their different properties.
    Ex. Plastics and metals.

4. GREEN MATERIALS
    Green materials are materials that do not pollute the atmosphere and do not take too many resources away from nature. Ex. Bamboo

5. MACHINES
What is a machine? A machine is an object that help us to save time and energy.
How many types of machines are there? There are two types of machines: simple and complex machines.
What is a simple machine? A simple machine is a machine that has no or few moving parts.
What is a complex machine? A complex machine is a machine that has two or more simple machines working together.

Remember, Simple Machines are six: lever, wedge, inclined plane, pulley, secrew and wheel.

LEVER

WEDGE

INCLINED PLANE

PULLEY

PULLEY

SCREW

WHEEL

LEVER

WHEEL

LEVER