# Earth & Space Science: Session 7

## Lesson and Curriculum

Lesson at a Glance:
Curriculum:
Project ARIES
Topic: Moon’s distance from Earth

Kathy taught a lesson from Project ARIES, an astronomy-based elementary-level curriculum that she’s been working with since 1993, when she was asked to help pilot it with her students. “Project ARIES… gives the kids a reason to read, and they keep a journal, so they have a reason to write, so it incorporates a lot of our language arts skills and we have math right there too, especially with the scale and distance.”
The subject of the lesson was the Moon’s size and its distance from the Earth. In preparation for the lesson, Kathy had her students keep Moon journals in which they note the Moon’s shape, its location in the sky, and its distance from the horizon. She also engaged her students in informal discussions about the Moon — what did they know about it, how did they think it worked — and recorded their ideas.

In the first part of the lesson, the students, working in pairs, selected two balls or balloons that they felt represented the relative sizes of the Moon and Earth, and then stood a distance apart from one another that they felt represented the relative distance of the Moon from the Earth. After measuring that distance, the students took their objects outside, and Kathy explained how they could measure the angular size of the Moon with their pinky fingers, which is about half a degree. Kathy then had the students who were holding the model Earths stand against a wall while their partners, who were holding the model Moons, backed up until the model Moons appear as half a degree in angular size—that is, the same size as the real moon. Then, Kathy gave them a chance to trade the size of their objects, and had them work out how far away the Moon was from the Earth in Earth diameters.

After the lesson, Kathy observed, “In the first model they made, the Earth and Moon were very close together, and it wasn’t until they used angular size that they realized, that’s a lot farther than I thought. That’s a hard concept for them to gather… and it’s not something you can just tell kids, because they have no conception those kinds of distances and sizes.”

Kathy wanted her students to take three things from the lesson: that the distance to the Moon is farther away than the students thought it was; that the Moon is one-fourth the size of the Earth in diameter; and that the Earth is about 30 diameters away from the Moon.