2014138
Description
Flashcards by Khadijah Mohammed, updated more than 1 year ago
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Created by Khadijah Mohammed
almost 10 years ago
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| Question | Answer |
| What are hydrocarbons made up of? | Hydrocarbons are made up of chains of carbon and hydrogen atoms only |
| Name 3 fossil fuels | Coal, crude oil and gas |
| How are fossil fuels made? | |
| What's the difference between natural and synthetic materials? | Natural materials occur by other living things and synthetic materials are made by humans |
| Give examples of natural materials from plants | Wood and paper are both made by trees Cotton comes from the cotton plant |
| Give examples of natural materials from animals | Wool comes from sheep Silk is made by silkworm larva Leather comes from cows |
| Give examples of synthetic materials | All rubber used to come from the sap of the rubber tree. We still get a lot of rubber this way (e.g. for car tyres) , but you can also make rubber in a factory. The advantage of this is that you can control its properties, making it suitable for different purposes, e.g. wet suits |
| What synthetic materials are used in clothing? | A lot of clothes are made of man-made fabrics like nylon or polyester. As with synthetic rubbers, the properties of synthetic fabrics can be controlled by the manufacturer - e.g. you can make fabrics that are waterproof, super-stretchy or sparkly |
| Why is paint synthetic? | Most paints are mixtures of man-made chemicals. The pigment (the colouring) and the stuff that holds it all together are designed to be tough and to stop the colour fading |
| What is a melting point? | This is the temperature where the solid material turns to liquid. E.g. the melting point of water is 0 degrees Celsius |
| What is strength? | Strength is how good a material is at resisting a force. You can judge how strong it is by how much force is needed to either break it or permanently change its shape (deform it) |
| What is one of the types of strength? | Tensile (or tension) strength: How much a material can resist a pulling force. Things like ropes and cables need a high tensile strength , or they'd snap |
| What is the second type of strength? | Compressive strength: How much a material can resist a pushing force. Building materials like bricks need good compressive strength, or they'd be squashed by the weight of the bricks above them. |
| What is stiffness? | A stiff material is good at not bending when a force is applied to it. This isn't the same as strength - a bendy material can still be strong if a big force doesn't permanently deform it. |
| Give examples of stiff materials | Materials like steel are very difficult to bend - they're very stiff Some kinds of rubber are very strong but they bend and stretch very easily - they're not stiff. |
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