Years 3 & 4 have been learning about how scientists use classification keys to identify living things, based on their observable characteristics (the things that you can see).
We used keys to sort different pond animals, in order to identify them, then made our own keys in order to identify a different set of animals. The skill was in selecting the most appropriate questions, which can only be answered yes or no.
We then went to the wildlife area and found fallen leaves before using observable characteristics such as stem, leaf edge, grouping etc. to sort ourselves into groups according to which leaves we had.