A researcher rolls some clay into a ball and shows it to Zian, then squishes the clay into a pancake. Zian understands that the amount of clay is the same in both. The researcher makes a row of 10 coins, then makes another row of 10 coins beneath it but spreads out the row so the coins are farther apart. Zian says the spread-out row has more coins in it. This seems to confirm the phenomenon Piaget called:
