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Speaker 1: Welcome to brain Stuff from how stuff works dot com

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Speaker 1: where smart Happens. Hi. I'm Marshall Brain with today's question,

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Speaker 1: what do the little recycling symbols that you see on

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Speaker 1: some plastic items mean? And how many different symbols are there?

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Speaker 1: A typical symbol looks like a small triangle with a

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Speaker 1: number inside of it. There are seven of these symbols currently,

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Speaker 1: each one identifying a different type of plastic. Here are

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Speaker 1: the types. Number one is polyethylene tariff thalite or PET.

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Speaker 1: Number two is high density polyethylene or HDPE. Number three

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Speaker 1: is polyvinyl chloride or PVC. Number four is low density

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Speaker 1: polyethylene or l d p E. Number five is polypropylene

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Speaker 1: or PP, number six is polystyrene or PS, and number

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Speaker 1: seven is other resins like a BS. PET is most

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Speaker 1: commonly seen in plastic soda bottles in my lar film.

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Speaker 1: High density polyethylene is what milk jugs are made of,

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Speaker 1: and it's also used in things like plastic gas cans.

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Speaker 1: PVC is the base for any form of vinyl, from

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Speaker 1: vinyl siding to vinyl seat covers, as well as many

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Speaker 1: soft toys. Low density polyethylene is found in things like

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Speaker 1: plastic food, containers. The difference between high density and low

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Speaker 1: density is that low density polyethylene is softer, more flexible,

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Speaker 1: and melts at a lower temperature than high density. Polypropylene

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Speaker 1: is a lightweight plastic and has a relatively high melting point.

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Speaker 1: It's used in things like luggage and plastic trim for cars,

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Speaker 1: as well as some food containers. Polystyrene is commonly known

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Speaker 1: by the styrofoam brand name and is used in everything

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Speaker 1: from coffee cups to coolers. These symbols only scratch the

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Speaker 1: surface of the hundreds of different types of plastics around you.

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Speaker 1: Think about it for a second and you can understand

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Speaker 1: the variety of plastics in use today. A there's nylon, polyurethane, polyurethane, foam,

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Speaker 1: all sorts of non melting plastics used in cookware. There's

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Speaker 1: a poxies, fiberglass, polycarbonates, and so on. We've still got

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Speaker 1: a really long way to go before they're all recyclable.

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Speaker 1: Do you have any ideas or suggestions for this podcast?

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Speaker 1: If so, please send me an email at podcast at

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Speaker 1: how stuff works dot com. For more on this and

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Speaker 1: thousands of other topics, go to how stuff works dot com.