Rocks Tell Us the Moon's Story
How do we know about the Moon's long history? The rocks themselves record it. Children can see snapshots of the Moon's history and hold an important artifact of American history with a Lunar Sample Disk. Earth rocks and soil of similar types as the lunar samples may be provided and explored with hands, eyes, noses, and tools! This activity may stand alone, but it is recommended as a station in Growing Up Moon.
What's the Point?
- The lunar samples collected during the Apollo missions are a national treasure and provide invaluable scientific insights into the age and nature of our Moon.
- Scientists are continuing to investigate the lunar samples using new techniques and tools.
- The samples have unique features, which were shaped by processes in the Moon's history and ongoing impacts by asteroids and comets.
- Similar types of rocks exist on Earth, shaped by processes of melting, volcanism, and impacts.
- Weathering and plate tectonics destroyed Earth's oldest rocks.
- The Moon has rocks older than any that have been found on Earth, and they record a valuable early piece of the Earth and Moon's shared history.
For the group:
- Lunar Sample Disk
- 2 (or more) magnifying glasses
- Optional: stereo microscope and an electrical outlet
- Optional: Earth rock samples, including anorthosite, basalt, and breccia, ordered from a natural science catalog such as WARD'S Natural Science
- Optional: 1 local soil sample in a small, open container
- Images of the oldest rocks
For the facilitator:
- Background information
- Shopping list
- Snapshots of Distant Time
- Optional: a partnership with the geology department at a local university, museum, or science center
- Contact the Lunar and Meteorite Sample Disk Program at the NASA Johnson Space Center. Request participation in a training program to become a certified user of the disks. Following the training and at least six weeks prior to the requested loan date, submit a written request to borrow an educational sample disk. The Johnson Space Center Curatorial Office, Lunar and Meteorite Sample Education Disk Program will respond via email with further information.
- Identify a secure location to store the Lunar Sample Disk when it is not in use. NASA requires the disk to be stored in one of the following locations, which may not be at a personal residence.
- Safe, with built-in combination lock
- Steel cabinet, with lock bar and combination lock
- Vault, with combination lock
- Non-private bank vault
- Police Station
- If desired, contact the geology department at a local university, museum, or science center to coordinate on your program. They may be able to supply a guest presenter or lend a stereo microscope or Earth samples of basalt, anorthosite, and breccia (rock types which are also found on the Moon).
- Provide an area where the children can gather around the Lunar Sample Disk and take turns looking at the samples. Set out magnifying glasses, and if available, stereo microscopes near an electrical outlet.
- Collect a local soil sample from your nearby (perhaps from a field, a flower bed, or the area near a stream) and place it at the station for the children to investigate.
- Print the images of the oldest rocks and set them out with the Earth rock and soil samples in a nearby area. If possible, create a slightly separated area so that there are two centers of activity and not all of the children are waiting for a turn to see the lunar samples. Provide magnifying glasses at this location as well.
- Refer to Snapshots of Distant Time for talking points about the different lunar samples.
- The disk must be secured, while not in use, in a safe or vault-type safe or cabinet with a bar and combination lock; must be sent via registered mail to and from locations; and, must be under constant surveillance while in use.
A Word on Words . . .
The term "soil" is being used in this activity because children are familiar with "soil." "Regolith" is a more appropriate term and is explored in the activity The Scoop on Moon Dirt.
Soil: the unconsolidated (loose) top layer of material on Earth's surface that is made of minerals and, usually, organic matter in which plants grow.
Regolith: a general term for the layer of loose rock material that forms the surface of a planet — including Earth! — and covers the rock. Soil is a type of regolith. Other types of regolith include volcanic ash, materials deposited by a glacier or river, sand dunes, the red rocky surface materials of Mars, and the layer of material on the lunar surface.
Dirt: a term often used to describe soil.
1. Show the Lunar Sample Disk to the children and explain that these rocks and "soil" are actual samples that were brought back from the Moon by Apollo astronauts! Describe the technological effort and national pride involved in sending those astronauts to the Moon. Tell the children that the samples are very valuable, so they were set in acrylic so that they could travel around the country, visiting schools and libraries.
- Do the rocks look like what you expected? Accept all answers.
- Can you see more detail with the magnifying glass and/or the stereo microscope? What features become visible with these tools?
- What information do the children think scientists can learn from these samples? The children may have many ideas, including information about what the Moon is made of. Some children may have heard of radiometric dating — the process of acquiring an absolute age of a rock (or organic material) using the decay of radioactive elements contained in that rock.
Clarify that they might have heard of radiometric dating using the element carbon-14 (carbon dating), but carbon is only one of the elements scientists can use to determine the age of a substance. Carbon dating is useful for determining the ages of relatively young materials — up to about 50,000 years old. Other elements must be used to date older materials, including Moon rocks.
2. Use Snapshots of Distant Time to guide your conversation with the children and relate the samples to the station activities they explored in Growing Up Moon. Discuss each sample, explaining how it was formed and asking the children questions about it.
- Which station in Growing Up Moon described the time frame when this sample formed?
- How did this sample form? Refer to the Snapshots of Distant Time for descriptions of the various processes at work on the Moon, including melting and volcanism in its past and ongoing impacts by asteroids and comets.
- Which sample formed first? Anorthosite. Most recently? Breccias, soils, and basalts.
Add that breccias and soils have been forming throughout the Moon’s history, and they will continue to form through ongoing impacts.
3. As you discuss each sample, invite the children to touch an Earth rock or soil of the same type. Have them use magnifying glasses and their hands, noses, and eyes to note their features.
- How do the children think these samples formed? Does the Earth also have volcanos? Yes! Do rocks ever get hot enough to melt on Earth? Yes! Have meteoroids — including those large enough to be called asteroids — and comets ever hit the Earth? The children may recall that the dinosaurs went extinct due to an impact by an asteroid.
3. Show the children the images of Earth's oldest rocks as well as the oldest lunar rocks.
- Which are older? The Moon rocks.
- Why are there no rocks on Earth as old as the Moon's?
- What happens to rocks over time on Earth? They erode and eventually become recycled through Earth’s plate tectonics.
- What formed the breccia? Impacts.
- Do the children think impacts were also occurring on the nearby Earth 3.9-3.8 billion years ago? Yes!
Add that lunar rocks record not only the Moon's tumultuous past, but Earth's early and turbulent history. Since there no 4.5-billion-year-old Earth rocks have ever been found to show us that history, we can learn about those impacts from the Moon.
The Moon rocks are treasures to scientists and patriots! Tell the children that scientists are continuing to investigate the lunar samples using new techniques and tools.
- Are they treasures to the children as well? Have the children imagine what our world would be like if there were no Moon — and no Moon rocks.
- What do the children think we could we learn if we had even more samples from the Moon, especially from unexplored areas like the north and south pole and the far side of the Moon?
If they haven't already done so, invite the children to explore the processes that created each kind of lunar sample through the Growing Up Moon stations and through the night-viewing activity Moon in Action.