Speaker 1: Welcome to Brainstuff from house stuff works dot com where
Speaker 1: smart happens. Hi. I'm braining with today's question, how do
Speaker 1: plastics work and what is actually in a plastic? What's
Speaker 1: it made out of? If you were to crawl under
Speaker 1: your house and poke around, chances are that you would
Speaker 1: find quite a bit of a white plastic pipe. This
Speaker 1: pipe is made of a very common, long lasting, strong
Speaker 1: plastic called PVC or polyvinyl chloride PBC. Plastic can be
Speaker 1: found in lots of other places around the home, including
Speaker 1: vinyl siding and vinyl windows. Then there's the fake leather
Speaker 1: made of vinyl, found in everything from furniture to jackets,
Speaker 1: to shoes, and many toys are made of vinyl as well.
Speaker 1: And that is just one kind of plastic. Polyethylene is
Speaker 1: even more popular. You find polyethylene and everything from plastic
Speaker 1: container is two plastic bags, from garbage cans to garbage bags.
Speaker 1: You can even make bulletproof protection out of it if
Speaker 1: you make it thick enough. There are many other types
Speaker 1: of plastics in common use. There's pet plastic, for example,
Speaker 1: founding clear plastic bottles for soda, as well as carpet
Speaker 1: and clothing abs. Plastic makes everything from pipes to lego bricks.
Speaker 1: Polystyrene makes styrofoam as well as plastic forks and containers.
Speaker 1: The bottom line is that we find these different plastics
Speaker 1: everywhere we look, in almost any product we touch on
Speaker 1: a daily basis. To understand how useful plastic is, think
Speaker 1: about where we would be if plastic had never been discovered.
Speaker 1: Let's say you want a container for some shampoo. If
Speaker 1: there's no plastic, what do you use to make the container?
Speaker 1: There's wood, paper, pottery, glass, fabric, and metal. You can
Speaker 1: make the container out of glass, but what if you
Speaker 1: drop it? Or what about a computer keyboard? You can
Speaker 1: make it out of metal, but now it's a lot
Speaker 1: heavier and more expensive. Plastics are obviously handy, they're inexpensive, lightweight,
Speaker 1: and strong. Where do they come from and what makes
Speaker 1: them so popular? Let's start with polyethylene, since it is
Speaker 1: both the most common plastic as well as the simplest.
Speaker 1: A plastic like polyethylene starts with crude oil. If you
Speaker 1: look at crude oil, it contains chains of carbon atoms
Speaker 1: decorated with hydrogen atoms. Polyethylene begins with an ethylene molecule
Speaker 1: derived from crude oil. And this molecule contains two carbon
Speaker 1: atoms and four hydrogen atoms. To make polyethylene, chemists have
Speaker 1: to link these ethylene molecules together into long chains that
Speaker 1: are hundreds of units long. That's where the name polyethylene
Speaker 1: comes from. Your chaining together these ethylene molecules to make
Speaker 1: incredibly long chains. The long chains then knit together to
Speaker 1: create a strong, flexible plastic. If you think about it,
Speaker 1: polyethylene plastic is really nothing more than solidified gasoline. It
Speaker 1: contains exactly the same atoms, just slightly rearranged and organized
Speaker 1: into much longer chains. Therefore, polyethylene is going to cost
Speaker 1: about the same as gasoline by the pound, and it's
Speaker 1: also going to burn like gasoline. There's even a company
Speaker 1: that makes a machine to turn plastic bags back into
Speaker 1: liquid oil to be reused. PVC is very similar to polyethylene,
Speaker 1: except one of the hydrogen atoms is replaced by a
Speaker 1: chlorine atom. About half of the weight of PVC comes
Speaker 1: from chlorine, so you need less oil to make PVC,
Speaker 1: and that chlorine atom also adds some concerns when PVC
Speaker 1: gets thrown out. When PVC is incinerated, it produces dioxins,
Speaker 1: which are good for neither animals nor people. Some countries
Speaker 1: are therefore working to phase out PVC, either altogether or
Speaker 1: in certain kinds of products. The environmental problem is the
Speaker 1: only real down side to most plastics. One of the
Speaker 1: things that makes plastics so appealing is that they're strong
Speaker 1: and long lasting. But if plastics escape into the environment,
Speaker 1: those assets become liabilities. The plastics can last for centuries,
Speaker 1: and they are accumulating in the Pacific and the Atlantic
Speaker 1: oceans in areas called garbage patches. While the patches grow,
Speaker 1: there's no real proposed solution to eliminating them. The best
Speaker 1: defense against plastic pollution is collection and recycling. If labeled
Speaker 1: with a recycling symbol, it's easy to tell what kind
Speaker 1: of plastic you're holding in your hand. The symbol one
Speaker 1: or the letter's PET denote pet plastic. HDPE or two
Speaker 1: is high density polyethylene PVC, or three is polyvinyl chloride
Speaker 1: l DPE or four is low density polyethylene pp or
Speaker 1: five is polypropylene ps or six is polystyrene, and seven
Speaker 1: stands for everything else. The next time you pick up
Speaker 1: or touch a piece of plastic, which will probably be
Speaker 1: about three seconds from now, keep in mind what you're holding.
Speaker 1: It's a piece of solidified crude oil molded into the
Speaker 1: object you need. Be sure to check out our new
Speaker 1: video podcast, Stuff from the Future. Join how Stuff Work
Speaker 1: staff as we explore the most promising and perplexing possibilities
Speaker 1: of tomorrow. The House Stuff Works iPhone app has arrived.
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