I finished my podcast script and we recorded it on monday at lunch.
I’m starting work on another about crude oil
Here’s the script:
ALLOYS AND THEIR USES PODCAST
A: Hello! This is the C1A Revision Podcast on Alloys and their Uses.
B: An alloy is a metal which has been mixed with another element to give it better properties for a certain job.
A: One problem with pure metals is that they are too easy to bend because they are made of only one type of atom and arranged in a regular structure made of lots of layers which can easily slide over each other.
B: An example of this is iron. Pure iron is too soft for most uses so we alloy it with other elements to make steel.
A: Iron is usually alloyed with carbon and some other things depending on what the resulting alloy is supposed to be like.
B: Adding non iron atoms disrupts the regular structure because the atoms we add are a different size from the iron atoms already there.
A: This means the atoms aren’t in layers and can’t slide over each other very easily. We will now focus on the different types of steel.
B: Firstly low carbon steel is made of iron and a small amount of carbon, which is why it’s called low carbon.
A: It is cheap to make and easy to shape so it’s used in mass production.
B: Things like containers, cars, knives, machinery and ships are made out of it.
A: Moving on, high carbon steel is made from iron and has quite a lot of carbon in it.
B: It’s more expensive than low carbon steel. It’s strong and brittle and is used in cutting tools.
A: The third type is stainless steel.
B: Stainless steel is made from iron and contains 12.15% chromium and nickel.
A: It is hard, strong and resists corrosion. In other words, it doesn’t rust. We use it in cutlery and containers for corrosive things.
B: Steel isn’t the only type of alloy we use every day: bronze and brass are alloys made from copper.
A; Pure copper is soft and reddish. It is a good conductor of both heat and electricity.
B: If you add tin to copper, you get bronze, which is low friction and used in statues and bearings.
A: Brass is made by adding zinc to copper. It’s much harder than copper but is workable. We use it in musical instruments.
B: Gold is used in jewelry but it’s too soft to use when it’s pure. To make it harder it is alloyed with metals like zinc, copper and silver.
A: Doing that also makes it cheaper and makes it look better. Aluminum is a low density metal which is easily shaped and a good conductor of heat and electricity. Density is how much matter is packed into a certain amount of space.
B: Aluminum has hundreds of alloys, all with different properties. Mainly though we alloy it to make it stronger and to go in aircraft.
A: The final topic in this Podcast is Smart Alloys, the ones that remember their shape.
B: Their technical name is Shape Memory Alloys or SMAs for short.
A: They remember their original shape so if you deform it (or bend it out of shape) it will return to normal after it is heated.
B: SMAs have lots of interesting uses, especially in medicine where they are used in braces and things to hold blood vessels open.
A: Unfortunately, they are more expensive than normal alloys and metals.
B: That concludes C1A Alloys and their uses. Thanks for listening and good luck!
I’ve been thinking about setting up a revision blog. (I used to be thinking about writing a revision guide but I decided a blog would be much easier and more accessible since I probably wouldn’t be able to get the guide published.