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
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.
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.
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).
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
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.
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.
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.
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.