How Does that Work: Is All Plastic the Same?

Go through your recycling and pull out several different plastic containers. Cut up the different types and place each in water.

What happens?

Sorry - the PET disappears in the water, but it's there, on the bottom.

PET plastics (soda bottles, #2) will sink. HDPE plastics (milk jugs, #1) will float.

There are lots of different directions you can go from here:

-What do PET and HDPE stand for?

-What are they each made of?

-Why does milk get packaged in HDPE but soda and water in PET?

-Is the recycling process different for the different types of plastics?

-Is one type of plastic more environmentally sound than another?

I'll admit, I don't entirely understand the differences, but that doesn't stop me from sharing things with my students.  It's a great opportunity for us to learn together.