I'm always looking for things to make my son learn by doing. We did the Baggie of herbs in the window. Worked great.
I had buy green onions for a dish THH likes. Remembering that I once saw you could regrow them I googled and found out how. If you have never heard about it lucky you can learn with us.
All you need is:
Green onions, cut to about the white part
You put the opinions in the jar, full it slightly with water.
Keep it watered and they should grow. Simple enough right? Lets hope it works.