Earth Day ideas using knitting

My assistant principal has asked me to put together an Earth Day program for our k-6. I’m almost finished with the power point on the history, etc. but I need some demos. I want to use plastic bags cut into strips and knit something small (maybe square coasters). Should I use a certain type of needle? Plastic is not that easy to work with. I’m also thinking of using strips of material. This is just 2 of my ideas (I want to show off my knitting). Any ideas will be appreciated and needle recommdations really appreciated.

I recently saw this on knitty gritty.

Here’s one using crochet - http://www.marloscrochetcorner.com/Plastic%20Bag%20tote.html

You could use the same technique and needle size and try out a coaster if you don’t want to do something as big as a tote.

Good luck!