Teaching Science: How Do You Classify a Group of Items?

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Prelab Discussion

Have students read the entire lab. Discuss these points before beginning the activity.

  • Discuss the five-kingdom classification system.
  • Discuss how physical characteristics can be used to classify things. Give examples from students' experience.
  • Ask students if they think there is a single best classification scheme.

Materials and Preparation

Materials needed:

  • container of assorted washers and nuts
  • piece of butcher paper
  • pencil

Download a copy of the classification chart and replicate it on the butcher paper. Leave room to make the chart larger. Show all your groupings of objects in the chart.


  1. Pour the contents of the container onto the table. Divide the contents into two groups based on similar characteristics.
  2. Record the name and characteristics of each group on your chart.
  3. Divide each of the two groups into two or three smaller groups. The items in each group must share at least one common characteristic. Give a name to each group based on the group’s characteristics.
  4. Record the characteristics of each group on your chart.
  5. Continue to separate the items into smaller groups until each group contains only one type of item. Remember that items in a group must have characteristics that make them different from the items in the other groups.
  6. Record the characteristics for each of the groups that you make on your chart.
  7. Share your chart with your classmates. Communicate what characteristics you chose to distinguish each group.


  1. How is your chart different from those of your classmates? (Answers will vary, but should mention and describe other groups' charts.)
  2. Which groups were the easiest to distinguish between? The most difficult? (Students should give their first major grouping, such as washers versus nuts, or big versus little.)
  3. Observe: Choose one item. Using the chart, record all of the characteristics for that item based on all the different groups it belongs to. How does the name you chose for that item reflect its characteristics? (A useful name will include characteristics that distinguish the item from all other kids of nuts or washers.)
  4. If someone picked an item from the group at random, how would you describe to that person how to classify it the same way you did? Write a set of step-by-step directions that someone could use to classify any item from the group. (Directions should clearly describe each trait that corresponds to a division on the chart. The most complete sets of directions will function like dichotomous keys.)
  5. How does your chart model the classification of organisms in an evolutionary tree? (The chart models an evolutionary tree because it groups items based on similar characteristics and it moves from less similar to more similar as you read outward.)

Ideas for Extending the Activity

Imagine that your washers and nuts are organisms and that they have evolved to reach their present forms. Describe all the steps in the evolutionary process you recorded in your chart.

For an extension activity, make a classification chart for other items, such as nails and screws, or items in a desk.