This is a great little activity and works if you like by mudflats (for lug worms and rag worms) as well as worms in your garden. Just replace the soil and sand with seaside sand and mud!
You will need: An empty jar (larger the better), 1/4 cup of gravel per jar, dirt, sand, leaves and grass clippings, a little water, a little water and a few worms...
Make the jar nice and damp (we will filled it with water, then tipped it out again). Pop the gravel in the bottom of the jar to give you a small base. Then, pop a layer of soil (at least 2 cm deep) in. Add a layer of sand on top (again, 2 cm deep). Now alternate with layers of dirt and sand. (about 2cm each layer). Once you are near the top, make sure the last layer of dirt is double the thickness to give the worms room to start. Add 2 table spoons of water into the jar so it it nice and damp.
Finally, pop the worms into the top, and sprinkle the grass cuttings and leaves over the top. Then set somewhere to let the worms get digging. We put ours into a cardboard box as we found the worms are more lively when its dark, but this is not essential. Revisit every now and again and see if your layers have moved!
Don't forget, if you keep them for more than 24 hours then you need to keep making sure the soil is damp. Keep popping a tablespoon of water in each day. After 5 days (max) the worms will need some outdoor space so make sure you set them free in the garden and then you can do it all over again!