Learning Planet Sizes


In this activity, learners use the concepts of greater than, less than, and equal to, in order to classify student height, object size, and planet size. They will build scale models of the planets based on their discoveries of planet size.

In the extension, advanced learners download images of the planets and use NIH Image to identify and describe their size by comparing them to one another.

Learner Outcomes 

The learners will:

  • measure and compare sizes of other classmates, classroom objects, and planet images by using different measuring units.
  • learn and distinguish the differences between the greater than, the less than, and the equal to signs.
  • compare the size of Earth to other planets.
  • list planets in order according to size.
  • represent planets by making selections for "scale models" from various balls and other spherical objects.
  • build their own "scale models" of the planets from clay, paper mache, balloons or other appropriate materials.
  • National Science Education Standards

    National Mathematics Education Standards

    Materials and Technology

    Scientific Background

    Teacher Lesson Plans

    Activity One: Develop background for understanding less than, greater than, and equal to by using familiar objects
    Activity Two: Measuring the size of a variety of objects 

    Activity Three: Comparing the Sizes of the Objects Measured 

    Activity Four: Concept Application: One to One Correspondence of Objects 

    Activity Five: Exploration of Scale Models 

    Activity Six: Concept Application: Scale Models to Planet Size