The Moon MEL

The Moon MEL asks students to weigh the connections between evidence and alternative explanations about the formation of the Moon. Understanding how the Moon formed supports understanding of Earth's formation and early history.

Below are links to resources that will help students use the Moon MEL and learn more about fundamental scientific principles related to the Moon and its formation.


This article provides an introduction to the Moon MEL plus suggestions from classroom use including management tips, potential problems, and activity extensions.

TES Moon Article Front Page
Understanding the Formation of the Earth's Moon (Acrobat (PDF) 822kB Jun4 18)

Next Generation Science Standards Performance Expectation

HS-ESS1-6: Earth's Place in the Universe

  • Apply scientific reasoning and evidence from ancient Earth materials, meteorites, and other planetary surfaces to construct an account of Earth's formation and early history.

The Models

Model A: The Moon was an object that came from elsewhere in the solar system and was captured by Earth's gravity.
Model B: The Moon formed after a large object collided with Earth and material from both combined to create the moon.

Student Handouts

Lines of Evidence

Evidence #1: Earth's average density is higher than the Moon's.
Evidence #2: Simulations of other star systems show that planets form when smaller objects collide.
Evidence #3: The Moon's orbit around Earth is tilted compared to Earth's orbit around the Sun.
Evidence #4: The composition of Earth and the Moon is similar near their surfaces. Their cores are different.

Student Handouts

Other Resources

This Plausibility Ranking Task (PRT), which may be completed prior to using any MELs, helps students to understand the role of evidence in supporting or refuting models.