ITEEA The Elementary STEM Journal, Vol. 23, Issue 4
PublisherInternational Technology and Engineering Educators Association, Reston
ReleasedMay 1, 2019
The Elementary STEM Journal, Volume 23, Issue 4 - May, 2019

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Activity: Worlds of the Solar System


Worlds of the Solar Systemimage.png

by Douglas Lecorchick and Charlene Detelich


This lesson aims to help students gain a better understanding of how diverse the worlds in our solar system are and give them a sense of scale as to how many solar system objects there are. Students will research a planetary world and record a few facts, just as an actual planetary scientist would. They will also cut, color, and fold paper printouts of the different worlds into a sphere. Once the entire class is finished with their cutouts, they will turn them in to the teacher who will hang them around the classroom, along with the research sheets, so the students can visually understand how vast our solar system is.


Common knowledge is that our solar system has eight official planets, but what is and is not a planet? The rules to become a planet are decided by the International Astronomical Union (IAU) (IAU resolution B5) and include:

  1. The world is in orbit around the sun (any planets orbiting other stars are technically not planets, and by this rule, there are only eight planets in the entire universe).
  2. The world must have enough gravity to pull itself into a sphere (a video on astronauts using water in space to make spheres may be helpful).
  3. The world must have “cleared the neighborhood around its orbit,” meaning there is nothing in its path of substantial size.

This is why the large spherical bodies in the asteroid belt are termed “dwarf planets” rather than “planets"—because they have not cleared their neighborhood. Pluto was demoted from planethood in 2006 mainly because it has a moon, Charon, that is almost half of Pluto’s size (Stern et al., 2015). It is so large that it technically shares an orbital center with Pluto rather than the moon simply orbiting around the dwarf planet. Some scientists consider this a binary system (Richardson and Walsh, 2005), and because Pluto orbits around this invisible point, it does not technically orbit around the Sun. Pluto also orbits in the outer asteroid belt, also termed the Kuiper Belt, and because of this it has not “cleared its neighborhood.”

It is important for students to realize that these rules were arbitrarily created by a team of astronomers rather than geologists, and that geologists consider almost every spherical body in the solar system a planet. The field of “Planetary Geology” studies all bodies in the solar system down to the smallest asteroids and comets. By this definition, there are far more than only eight planets in the solar system, including moons and dwarf planets, some of which are larger than the planet Mercury (Showman and Malhotra, 1999).

This lesson aims to teach students about the worlds of our solar system beyond the main eight planets by focusing on worlds that are spherical. It is important to note, however, that the solar system is vast and consists of over 200 large bodies orbiting the Sun and orbiting other, larger, bodies.

worlds of the solar system lesson plan

Begin the class by explaining to students what the IAU rules for planets are (rules outlined in the background section). Once students understand what the official rules for a planet are, assign each student a solar system world from the list below to research (can be adjusted for class size). Be sure to hand each student a planet map template to color, cut, and fold into a 3D world:






























Students should spend 20-30 minutes researching (using the computer/iPad) and recording their findings (with pencil and research worksheet) about their world. Once students are done researching their world, students should use a pair of scissors to cut out the map of their world and use a glue stick to fold and assemble the tabs of the map to create a 3D model. Finally, the student will turn their planet in to the teacher who will attach the planet to a string and hang it somewhere visible around the classroom.

After the students have all turned in their worlds, discuss with the class how many different types of worlds there are across the solar system, from rocky planets, to gas planets, to ice worlds; emphasizing that the solar system is incredibly diverse. Be sure to also discuss with students the vast amount of worlds in the solar system and how there are almost eight times as many worlds as they created. A good comparison to use may be that the entire grade level (depending on the size of the school) would need to create a world to represent all of the worlds in the solar system. There are so many that there are still hundreds of worlds that humans have yet to visit with spacecraft, and we do not even know what they look like yet.


  • Research worksheets for each student (Figures 1 and 2). Available at:
  • Computer/iPad - internet access
  • Planet cutouts (15 faces model)
  • Scissors
  • Glue sticks
  • Hole punch
  • String (enough for all planets)

Worlds in the Solar System worksheets-p.1.jpg

Worlds in the Solar System worksheets-p.2.jpg

learning objectives

Learn the official definition for what is and is not a planet.

Understand the diversity of the worlds in the solar system.

Understand that there are more than just eight worlds in our solar system


Students will recite rules of what makes a planet.

Student will be able to describe what makes their world unique from others.

Student will be able to tell the teacher how many worlds exist across the solar system.


IAU 2006 General Assembly: Resolutions 5 and 6 (PDF). IAU. 2006-08-24.

Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., … Zirnstein, E. (2015). The Pluto system: Initial results from its exploration by New Horizons. Science, 350(6258), aad1815.

Richardson, D. C. & Walsh, K. J. (2006). Binary minor planets.

Showman, A. P. & Malhotra, R. (October 1999). The Galilean satellites. Science, 286(5437), 77–85.


Douglas Lecorchick is an Assistant Teaching Professor at North Carolina State University. Any questions or comments regarding this manuscript should be directed to

Charlene Detelich is an undergraduate student studying geology at North Carolina State University and has previous experience researching Mars as well as one of Saturn’s moons.