Re: How could I best re-create the moon's surface for teaching purposes?

How can you replicate the Moon’s surface in the classroom? This is an excellent question! The lunar surface is very different from the surface of the Earth. There is no water on the Moon to erode and redeposit rocks. There is no atmosphere on the Moon, to burn up meteorites before they hit the lunar surface. For these reasons, you can basically think of the lunar surface as having been bombarded by meteorite after meteorite, each breaking up the rocks a bit more and a bit more, for 4.5 billion years. So, the top ten meters of the surface is a very fine powder, with some sand-sized particles intermixed. Below this layer (called the regolith), there are larger pieces of broken up rocks and below that even larger pieces. You might imagine that, if the entire surface were solid, and meteorites hit it from above many, many times, then the top part would be completely destroyed and very fine-grained, while the layers below would be progressively less destroyed and therefore larger grained. The important thing to realize is that the part of the Moon’s surface that the astronauts walked on was very powdery. So powdery, in fact, that their suits were covered with dust all the time, as if they were walking on flour or chalk dust. There are larger rocks within and on top of the fine-grained regolith that the astronauts could pick up and bring back to Earth, but essentially the part they walked on was dust.

My first suggestion for creating the lunar surface in your classroom would be to create a larger scale model out of papier mache that would show craters and lava flows. Although the texture wouldn’t be correct, the general vision of what the Moon looks like (from orbit, for example) could be created from looking at various photos of its surface.

My second suggestion would be to create a cross-sectional column of the Moon’s surface. This might be a large clear tube filled with various materials to show the progression from larger rocks deeper in the Moon to the fine dust that covers its surface. I would recommend starting at the bottom with very large (hand-sized) rocks, then a layer of smaller stones, then a layer of coarse pebbles, then a layer of sand and finally a layer of flour or some other very fine-grained material (chalk dust or talc). As you add the next smaller-grained layer, shake the tube well so that the smaller rocks fall down and fill in the spaces between the larger rocks. When you get to the sand section, really try to fill in as many gaps as possible. This tube will be a cross-section of the Moon’s surface and show the different textures that exist at depth (up to about a half mile deep).

Finally, the best way to show your students what the Moon’s surface would look and feel like is to get a large plastic container and fill it with a mixture of about 75% flour and 25% sand. Then toss in a bunch of other sized rocks, from pebbles to larger hand-sized rocks. Even though the surface is very fine-grained, the astronauts (and your students) could still walk on it. The fine-grained material will also stick to your students’ hands, just as it did to the astronauts’ suits. And the extra rocks within the fine-grained powder will serve as the samples that the astronauts picked up to return to Earth. You can even use a small garden rake to "pick up" the samples, just as the astronauts did on the Moon (see the photo in the Teacher’s Guide referenced below). An added bonus would be for you to get a pair of thick winter gloves (not knit, but water-resistant) and have your students "feel" the lunar surface with those gloves on, since this is what it would have "felt" like to the astronauts!

Many good educational ideas and information can be found by searching the NASA web sites for "lunar regolith education" or some other combination of words like "Moon soil." Two I found in particular are A Teacher’s Guide to the Moon, which has a wonderful section on the lunar surface, soil, and regolith and includes many great images; and a class exercise compares the regolith on the Moon and Earth.