With hammer, hit one clay piece. Record what happened. Compare the cooked clay to the uncooked clay. The clay cracks or breaks. The clay shatters.
Cooked clay is ridged and breaks easily.
Uncooked clay can be molded and shaped. It does not shatter but it can be pulled apart. A dried clay object is likely to break if someone drops it or hits it hard. Have them compare list and speculate on what the objects would be made of if there were not ceramics.