After the kids took left over silt from the vials and looked at them carefully, we had to wonder if there is a rock particle smaller than silt.
We read a book about rocks, and moved on to the next activity in the FOSS module. We investigated the properties of even smaller rock particles in clay!
After the kids were playing with a ball of clay for a while, they looked at their hands and discovered the very thing layer of dust made by dry clay particles.
We learned that clay is made of pieces of rock even smaller than silt. The pieces of rock are so small, it is not possible for us to see them with the naked eye, or the hand lenses.
We investigated further by creating a pea-sized ball of clay and putting it in a vial.
The kids were extremely excited to use the clay to create figures. Big Sister made the horse above.
Here the kids had added some water to the vial containing the pea-size ball of clay. They ran around, once again, vigorously mixing the contents. It turned to a murky gray color. We set aside the mixture to rest overnight.
The next day, they observed a layer of clay at the bottom of the vial. They also observed their clay ball become smaller, and the water remained murky gray.