Classifying activity


  • The most basic science process skills include the following (NARST):
  • • observing
  • classifying
  • • measuring
  • • predicting
  • • inferring
  • • communicating
  • Classification is defined as ordering or sorting according to some criterion or rule. For example
  • • arranging fractions or metric units from smallest to largest (serial sort)
  • • sorting objects by living/not living (binary sort)
  • • use a dichotomous key to classify leaves or flowers
  • • arranging the elements into a periodic table


  • Exercise i: Provide students with a set of rocks (or buttons or pasta). Have students sort the objects into two sets and be able to explain the criteria that they used in their decisions.
  • Exercise 2: Discuss the different criteria that were used by each group. The teacher can add additional properties such as density or function. Students should then classify their samples according to the new criterion.
  • Exercise 3: Have students create a sorting tree (dichotomous key) so they can assign a unique set of properties to each object.
  • Exercise 4: Trade sample sets and/or keys and have them identify each object.


  1. Classification activities (links to a variety of activities)
  2. The Mendeleev Puzzle (complete activity)
  3. Classifying galaxies (from NASA, includes cards)
  4. Enchanted Learning - make a dichotomous key (includes a graphic organizer to make a binary tree)
  5. Creating a dichotomous key of shoes (activity)
  6. Rock sorting introductory activity (college level)
  7. Search Science NetLinks for specific activities that involve classification.
  8. Also see card sorts and compare & contrast