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Age that crater!

Created: 2022-08-03
Amee Hennig

In Age that Crater! students will learn about the existence of craters on the Moon and on other planetary bodies and how they occur. They can also learn how to approximately age these craters, comparing them to other craters. This activity gives young students an introduction to phenomena occurring in the Solar System and on our own Earth. This activity is a student-driven inquiry process employing the Predict, Explain, Observe, Explain (PEOE) model, encouraging students to engage their education through self-drive inquiry and investigation. This activity is aligned with the Next Generation Science Standards (NGSS) for elementary and middle school students.

  • A whiteboard or large pieces of paper and markers or whiteboard markers for students to work in groups to write down ideas;
  • Printouts of Moon Surface (one for each student): see attached file 2205_astroedu_MoonMap.pdf;
  • Printouts of “crater” stickers in three different colors (see attached file 2205_astroedu_crater-stickers.pdf): the sheets should be printed onto sticker paper and cut, so that each student can use stickers of different colors;
  • Printouts of examples pictures of planetary bodies cratered surfaces (see attached file 2205_astroedu_images.pdf) and a document with the explanation of the history of these cratered surfaces (see attched file 2205_astroedu_crater_determination.pdf): these handouts are for the teacher to show to the students during the lesson introduction. In a different organization of the lesson, the images can also be handed out to students to extend the activity with more examples of cratered surfaces to practice on;
  • Printouts of Worksheet (see attached file 2205_astroedu_worksheet.pdf) to be handed out to the students to compare and contrast different cratered surfaces;
  • Teachers are also free to expand the activity searching and printing other images of any planetary body or moon to be used in this activity: online image galleries from NASA that may be useful are found at: Moon - and other planetary moons (refine search to match your preference -;

Primary Goals

  • Know that impacts creating craters occur not only on the Moon, but also on the Earth and other planetary bodies in the solar system
  • Learn how to qualitatively age craters on planetary bodies

Secondary Goals

  • Understand basic differences between the Earth and the Moon and other planets and moons in the solar system
  • Understand that space debris impact planetary bodies (including the Moon, planets, and other planets’ moons
  • Understand that craters occur on any planetary body (including the Earth, the moon, other moons, and other planets)
  • Understand that impacts occur over time and not all at once
  • Understand that space debris impacts occur on a variety of planetary bodies, not just the Earth and Moon, by a variety of objects
Learning Objectives
  • Identify crater impacts on a variety of planetary bodies
  • Approximate order in which craters occurred on planetary bodies (i.e. in what order the impacts occurred)

The Big Idea

It is possible to qualitatively age craters on moon and planetary surfaces using images of the surface. This does not give the student a definitive age of when the craters occurred, but does allow the students to grasp the basic understanding that space debris will hit planetary bodies over a time and leave significant marks on the surface.

What is a Crater?

A crater is a depression in the surface of a planetary or lunar body. There are a variety of different type of craters such as those formed by explosions and volcanic activity. However, in this activity we are specifically focusing on craters produced by the impact of a meteorite or asteroid. This is called an “Impact Crater.” An impact crater will often have signs of that impact. Since this happens at high speeds and creates large amounts of pressure forcing the material in the ground downward there will be destruction in the immediate area and signs of debris.

How do Craters Form?

According to NASA, “Impact craters are formed when impactors such as meteorites smash into the moon's surface. The factors affecting the appearance of impact craters include the size and velocity of the impactor and the geology of the surface.” However, craters may occur on any planetary body, including other planets like Mercury or Mars and other planets moons such as Jupiter’s moon Iapetus. Additionally, craters even occur on planet Earth. For more about craters and to see how they are created, see this hands-on activity presented by NASA

Glossary of Useful Terms (fromNASA Space Place Glossary):

Asteroid – Rocks floating around in space. Some are the size of a pick-up truck. Others are hundreds of miles across.

Crater – A large, bowl-shaped dent in the ground. They can be caused by an explosion or the impact of a meteorite.

Meteor – The streak of light caused when a meteoroid enters a planet’s atmosphere and starts to burn from the heat of friction.

Meteorite – A meteoroid that lands on the surface of a planet.

Meteoroid – A little chunk of rock in space smaller than a pick up truck. If it were bigger, it would be an asteroid.

Moon – A natural object that travels around a bigger natural object. Planets can have moons. Dwarf planets can have moons. Even some asteroids have moons! Astronomers usually call them satellites or natural satellites.

Planetary Body – A large body in outer space that circles around the another star, but may not yet be classified as a planet.

Planet – A large body in outer space that circles around the sun or another star.

Full Description

Materials Setup (Before the activity starts)

  • Organize the room with the whiteboard and markers or with large pieces of paper and markers for students to write down ideas working in groups;
  • The worksheet (2205_astroedu_worksheet.pdf) should be printed and distributed to students;
  • Printouts of pictures of different planetary bodies are available to be displayed during the Lesson Part 1 (see 2205_astroedu_images.pdf) as well as the printout of the explanation of the history of these cratered surface (see attached file 2205_astroedu_crater_determination.pdf);
  • For Lesson Part 2, lay down on the tables for the students printouts showing the Moon 2205_astroedu_MoonMap.pdf and printouts of stickers 2205_astroedu_crater-stickers.pdf in a minimum of three different colours;
  • Teachers may also challenge the students to repeat the activity to attempt to approximately age the craters on a variety of other cratered surface, printing images of other bodies (see links suggested in List of material).

Lesson Part 1

Prediction 1

The lesson will begin with a discussion of the many planetary bodies within the solar system. This discussion will include definitions of what it means to be a planet and a moon. The discussion will also compare the Earth to other planets and the Moon to other moons in the solar system.

Students will be asked to predict how the Earth and Moon are similar and different to other planets and moons in our solar system. This will initiate discussion which will lead to the differences between the presence of craters on the Moon and the Earth. Some students may not believe or know that there are craters on Earth due to the fact that Earth’s atmosphere and composition allows for these features to be quickly changed and lost.

Explanation 1

Students will work in groups to write down their ideas predicting the similarities and differences between the Earth and Moon and other planets and moons (using 2205_astroedu_worksheet.pdf) Each group of students is asked to explain their list and why they predict what they do about the similarities and differences.

Observations 1

The teacher will then put up pictures of the Earth and the Moon as well as other planets and moons, without explaining which are which (see 2205_astroedu_images.pdf). The teacher will allow the students to observe the various pictures and make guesses about whether they are other planets and moons or our own Earth and Moon. (correct answers are in 2205_astroedu_crater_determination.pdf).

Explanation 1

Students should begin to understand that there are many features of our own Moon and Earth that also appear on other planetary bodies. The teacher will begin to reveal which of the pictures are from our own Moon and Earth and the students will then be asked to explain how they are similar and different again.

One major difference that should stand out is the presence of craters. Students should notice that there seem to be many more craters present on the Moon and on other planetary bodies. This may be expanded into an additional PEOE scenario or the teacher may choose to directly explain how the presence of an atmosphere, the elements, plant life, etc. changes Earth’s surface so that craters are less likely to be preserved for long periods of time on Earth.


Lesson Part 2

Prediction 2

Now that students understand the features of craters on Earth, the Moon, and other planetary bodies the teacher can move on to the next section of the activity. In this part of the activity the teacher will pass out the papers that show the moon-surface or planetary body and the “crater” stickers ( 2205_astroedu_crater-stickers.pdf and 2205_astroedu_MoonMap.pdf).

Before giving the students instructions for the next step the teacher will ask students to predict how they will be able to tell the ages of the craters. The teacher should have the students write down their ideas for what features will tell them the difference between a new crater and an old crater.

Explanation 2

Next, the students will be asked to explain the various reason they chose for how to tell the age of the craters. There can be multiple answers for this that are correct, but this activity will teach the students how to qualitatively age craters based on craters relation to other craters on the surface.

Observations 2

Now that the students have been asked to make their predictions and explain their predictions the teacher will instruct them to begin placing the stickers on their moon. Each type of stickers should be placed at the same time, and any stickers of the same colour cannot touch (i.e. all blue stickers should be placed at the same time, and none of them can touch. Then all of the red stickers may be placed at the same time without touching any other red stickers, however, the red stickers may overlap or touch the blue stickers, and so on until all stickers have been placed).

After all the stickers have been placed the students should be asked to observe their moon-surface and compare them to the images that they’ve observed of other planetary bodies.

What do they notice about their own moon’s surface and the pictures of the other planetary bodies? Similarities? Differences?

Please note: The students may place the stickers however they like, but the students should be given enough stickers that it becomes impossible for them to not have to overlap stickers of different colours.

Additional Note for Teacher Guidance: The teacher should keep in mind the goal of leading the students to discover that if you have three craters that are overlapping you can observe and conclude the one on the bottom is the oldest and the one on the top is the youngest, while the middle crater happened sometime between the other two. This does not present exact ages or times between occurrences but can lead to the discovery of relative and general timing of occurrences between each crater relative to the others.

Explanation 2

The students are asked to again explain ways that they can tell the ages of the various craters and record them together as a class. Then the students are encouraged to come together as a class and decide the best way to qualitatively age the craters.


After the activity students should be able to look at any pictures of planetary bodies and be able to identify the craters and the and qualitatively age them. To test this understanding a teacher may want to supply a number of different pictures of real moons and planets and ask the students to identify and qualitatively age the craters on the surfaces of the planetary bodies.


According to the NGSS standards:

- ESS1.B Earth and the Solar System: The solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the sun by its gravitational pull on them. (MS-ESS1- 2),(MS-ESS1-3)

- MS-ESS 1-1 Patterns: Patterns can be used to identify cause and effect relationships.

- MS-ESS1-2 Systems and System Models: Models can be used to represent systems and their interactions.

- MS-ESS1-3 Earth's Place in the Universe: Analyse and interpret data to determine scale properties of objects in the solar system.

Connections to Nature of Science: Scientific Knowledge Assumes an Order and Consistency in Natural Systems. Science assumes that objects and events in natural systems occur in consistent patterns that are understandable through measurement and observation.(MS-ESS1-1),(MS-ESS1-2)

Additional Information

Additional activities are available to expand the learning through the use of an activity sheet or through teacher-created challenges for the students to apply their new knowledge to other planetary bodies in the Solar System. Additionally, this activity may lead into classroom or outside-classroom use of the Zooniverse’s Moon Zoo online activity.

Further Reading

Useful Websites and Additional Resources:

  • NASA | Space Place

What is an Impact Crater?
Offers a short explanation and pictures of multiple types of impact craters. Pictures include 1) Earth: Meteor Crater, 2) The Moon, Tycho Crater, 3) Earth, Vredefort Crater

Where did all of Earth’s craters go?
An explanation for why we do not see craters on the Earth as prominently as we do on the Moon.

  • LPI | Education: Shaping the Planets: Impact Cratering
A detailed website with explanation, glossary, and images of craters.
This site offers additional background that the teacher may find useful when preparing the lesson based on the level of detail he or she would like to go into.

  • Smithsonian Air and Space Museum | Impact Features
Additional images and explanations that detail different impact craters that occur on the Earth, the Moon, the planets, and even asteroids.