MAKE – 2b. Materials & Components (Functional properties)
All Materials have key features, functional properties, that describe how they behave when work is done to it e.g how tough, hard, flexible, malleable the material is.
How do you workout what material you have?
It’s about practice and building up a knowledge base.
Hopefully you know what Metal, Plastic and Timber (Wood) looks like, well after that you start to look for other clues.
With metals does it have iron in it? If so it is from the ferrous family so it will be magnetic otherwise it will be non-ferrous and non magnetic.
Timbers can be broken into three main types, Softwoods, Hardwoods & Manufactured boards. Softwoods are more often pale in colour and the grain (lines) are wider apart, while Hardwoods are mostly darker and the grain quite close.
Manufactured boards are man made so are bits of old timber that has been glued together to make big panels e.g chipboard.
Can you explain some of the technical terms so it is easy to understand?
When talking about resistant materials, Metals, Timbers and Plastics, you will hear terms such as Strong, Hard, Soft, Brittle, Tough, Ductile, Malleable, Resists wear, Good / Bad Conductor(heat or electricity), Close grain, Open grain, Straight grain, Stiff and Flexible. All of these terms describe what happens to the material when work is done to it; basically if it is hit, squashed, or twisted. Check out the PowerPoint on this page for the terms above to be described in full.
Why do different materials behave differently?
It’s all about the science! Materials are natural forms, take trees did you know they grow? They drink, eat, breathe and grow. When they are cut down you have to wait for the moisture to dry out before you do anything with them otherwise they will twist and bend. Once they have dried out (seasoned) they will behave differently depending on the way they have been cut; this is down to the direction of the grain (lines). You need to think about what strain the design product you are making will be under and what you need it to do. When it comes to Metals and Plastics, think about a Lego structure you know how to make them stronger and weaker, well it works a little like that but a lot more maths and science.
Can you mix different materials together?
Easy answer is yes, well sort of. When you mix metals together you get something called an alloy. You can pick the best properties from different materials and bring them together but you also bring their weakness with them as well. When is comes to timbers we are talking manufactured or engineered boards. You can make the boards lighter by making them hollow, doors are a good example. Try knocking a door and listen to the sound, the doors at school will probably be heavier and sound heavy, while the inside doors at home could be lighter and sound hollow when knocked. Plastic materials are treated just like the metals. The best properties of a group of polymers can be brought together to perform at their best for a job they have been designed to do. When you look at your clothes it might say natural fibres or man made or a combination of them. The fibres have been combined to suit the job they have been designed to do. When it comes to food as a material it’s a piece of cake, or is it bread or pastry…… basic ingredients combined together in different quantities and orders. It’s what we’ve been talking about.
Saw Mill Tips and Identifying Wood.
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