Materials and their properties.
We take many materials around us for granted. Everyday we use things without knowing very much about them. This session we are going to classify materials into two groups. Natural and Man-made.
Natural materials
These are materials that are found around us. We may have to dig them out of the ground, grow them, or take them from living things
These are some of the Natural materials around us that we use everyday:
Wood
Wood is very useful to us. Wood can be cut into different shapes. It is hard wearing. It is abundant (easy to get at), reasonably cheap and very attractive.
Think of some ways in which we use wood every day
Furniture
Frames for doors
Shelves
Are some of the ways in which we use wood. I bet you thought of many more!
There is a drawback to using wood. It takes many years to grow trees. We are cutting down trees that should really be left alone. Remember every tree is the home to something?
Many trees are now being planted to be cut down, so that the natural forests remain.
Leather
Leather comes from animal skins. It is very useful for making hard-wearing clothes and shoes.
Oil
Crude Oil is one of our most precious resources. It is found underground and needs to be piped out from deep below the Earth's surface We depend very much on oil, oil is used to help keep the transport system moving. It is used to make petrol and it is even needed to make soap! Oil is used to make plastics.
Now look around you and see how much plastic there is near you. Imagine how mush plastic there is in the world. You can see how much oil we need.
Crude oil is not the only oil we use. We can get oils from plants (sunflower oil, olive oil, walnut oil. All these oils are useful to us.
Coal
Coal is a valuable fuel for us. Coal is dug out from underground mines. We use coal to keep our power stations running and providing us with electricity.
Cotton and silk
We grow cotton on plants to make clothes for ourselves. Silk is taken from the cocoons of moths and spun into a very fine material for clothes.
Iron
Iron is dug out from the ground. We use iron in making strong buildings.
Man-made (synthetic) syn-thet-ic
We can use many natural materials and by working with them change them into man-made substances.
We have all ready talked about oil (natural) being changed into plastic (man-made).
Here are some more:
Sand (natural) being heated and made into glass (man made). The silicon chip inside this computer is made from sand.
Wood (natural) being made into paper (man-made).
Oil (natural) being made into nylon (man-made).
There are a great many man-made substances that we use everyday.
Remember if we change them into something else, they are man-made.
Here is a list of materials can you say which ones are natural?
Click the natural materials
Well that just about covers natural and man-made materials. How did you do?
Here is the table again and the natural materials are in bold.
|
Wood |
Leather |
Nylon |
|
Paper |
Oil |
Rayon |
|
Chalk |
Gold |
Cotton |
|
Fibreglass |
Coal |
Sand |
|
Silk |
Plastic |
Tin |
Good luck