Recycling makes you feel good -- but what actually happens to all the plastic bottles?

This ...

Does not happen.

Bottles do not magically become fresh new bottles.

The story is actually much more interesting.

We're going to focus on polyethylene terephthalate or PET, the type of plastic with a "1" printed on the bottom.

The ethylene terephthalate refers to this.

String a bunch of these together and you get polyethylene terephthalate: a durable, flexible plastic that can be heated up and molded into lots of convenient shapes.

After you recycle a plastic bottle, it gets hauled off and sent to a recycling plant.

They take off the labels and clean it and separate all of the PET bottles, not just from the glass and metal and paper, but also from the other kinds of plastic.

That's because different types of polymers do NOT always play well together.

For example: polyvinylchloride [PVC], which most of the pipes in your home are made of, can totally ruin a batch of PET.

You have to heat up a batch of PET so much just to soften and mold it that the PVC will start to chemically break down and produce hydrochloric acid, which can actually degrade the PET.

So sorting is super important, and so is cleaning to remove as much impurity -- in this case, things like that last, spitty sip of soda, or other types of plastic -- as possible.

That's one major factor in why it's hard and expensive to recycle bottles into more bottles.

But when the plastic isn't good enough for recycling into more bottles, it's still sometimes good enough to spin into fiber for clothing or carpets or...whatever else you need fiber for.

Which, incidentally, is now called polyester even though chemically, it doesn't change.

That's right folks, most polyester and PET plastic are chemically the same thing.

The plastic is just ground and shredded and melted until it can be spun into thread and then woven into fabric.

This type of recycling is sometimes called downgrading, because once the plastic becomes fabric, it can no longer be recycled again.

There is also a form of recycling that changes the chemistry of PET.

And is in fact called... chemical recycling.

It requires putting enough energy into the plastic to break the chemical bonds holding the polymer together, converting PET back into its individual parts.

These molecules can be used to re-make PET, or even made into different types of plastic.

But chemical recycling is really expensive so we don't do it much.

So that's why bottles become clothes, and not new bottles: because making bottles requires super clean plastic, and that's tough to get.

But even though going from a plastic bottle to a handbag is technically a downgrade, at least it's much cuter now, right?...

right?