Duration: 30 minutes
SPIRIT Skills:
Brief Description:
Afterwards, they investigate how to play with the size and depth of craters from
gravity.
Students receive a box with various stones and a sandbox.
A. They may freely explore crater formation.
(e.g. guiding questions: create craters of different sizes/depths.
How can you make the largest / deepest craters?)
Briefly discuss what they have observed.
Encourage them to describe their observations as precisely as possible!
Optionally compare the craters made by the children with photographs of real craters on the Moon.
B. Then move on to a focused investigation.
Central research question:
What determines the size (depth and width/length) of a lunar crater?
Ensuring a fair test (explicitly explain to students)
- Always drop from the same height.
- Hold the stone still and simply let it fall (starting speed always zero).
- Always drop straight down.
- Change only one variable at a time (e.g. not comparing large and heavy with small and light).
- Smooth the sand after each test.
Guided investigation steps
B1. The role of mass (weight) of the stone
- Hypothesis: The heavier the meteorite, the deeper the crater will be.
- Use objects that are the same size but with different mass.
- First let students sort stones into two groups: light and heavy.
- Discuss together how they can judge if something is heavier or lighter.
- Then let them test: take two stones of the same size but different mass and compare crater depth.
B2. Do heavy and light stones (same size) fall at different speeds?
- Likely, students think a heavier stone falls faster.
- Let them test: drop a heavy and a light stone from the same height at the same time.
- They discover: both hit the ground simultaneously → surprise → discussion: Why is that?
- Key concept: mass does not affect falling speed.
- Follow-up: if they fall at the same speed, why is one crater bigger/deeper? → Because of the impact force.
B3. The role of size of the stone
- Use objects that are equally heavy/light but differ in size.
- Compare the craters formed
How does this develop particular SPIRIT skills
This phase significantly promotes critical thinking, curiosity, wonder, and openness, as well as scientific questioning, as it guides children from unstructured play toward systematic observation. Through interaction with the physical environment—specifically, by using the sandbox and various types of rocks—students actively practice the skills of observation, formulating and testing hypotheses, and isolating and identifying variables. At this stage, children discover gravity through hands-on experience, which helps them think like “scientists.” By playing with different rocks in the sandbox, they learn to observe small details and ask questions (“What happens if…?”), which lays the foundation for their critical thinking. When they realize that they need to change their strategy for the experiment to succeed (for example, how to drop the rock), this directly develops their problem-solving skills. This activity guides them from passive reception to active discovery, where they discover cause-and-effect relationships (weight of the stone = depth of the crater) on their own, rather than having them handed to them
What do we want to achieve regarding SPIRIT skill development (student understanding and/or behaviour)?
As the result of this stage’s activities, we want to achieve the follovings:
- Observation-based Critical thinking: We want the children not only to “throw” the rocks but also to observe what happens. The goal is for them to try to describe exactly what they see: “Look, this rock made a hole as big as a palm!”—this is the first step toward scientific observation.
- Experiment-Based Problem-solving and discovering Cause-and-Effect Relationships: The goal is for them to learn, in accordance with their age-appropriate characteristics and knowledge, the connections between the experiment and the underlying causes. A key objective is for children to discover simple cause-and-effect relationships on their own. For example, that the heavier stone creates a deeper crater because it hits the sand with greater force. This doesn’t need to be explained to them; instead, they should be allowed to see it with their own eyes during the experiment.
- Curiosity and Openness – experiencing Wonder: We want the children to be excited by the discovery. When they realize that heavy and light stones hit the ground at the same time, their surprise is the most important part: this helps them remain open to new ideas and not just believe what they had assumed beforehand.
Academic/Curriculum Objective connection
- Exploring gravity and the force of impact.
Materials and tools needed for implementation
Sandbox, stones, measuring tools, windscreen wiper.
Preparation notes
To carry out this section effectively, teachers should prepare sandbox boxes and create a collection of rocks in advance, with stones of varying weights and sizes. It is helpful to have photographs of real lunar craters on hand to bridge the gap between the classroom experiment and reality. Before beginning, the teacher should briefly explain how to conduct a “successful experiment.” This includes introducing the students to specific procedural rules: the rock must always be dropped from the same height; before dropping it, the student must ensure that the rock is completely motionless so that its initial speed is zero; the rock must be dropped straight down; and the sand must be smoothed out after each trial. Teachers should also be prepared to guide students through the sorting process, helping them categorize the stones into “light” and “heavy” groups to facilitate comparison.
The teachers have to:
- Categorize the stones beforehand into lighter and heavier, smaller and larger.
- Carry out the research question and procedure step by step with them (providing more whole-class guidance).
- Provide individual support for a group.
Guided Questions
- Are there light and heavy stones or are they all the same?
- Which stone created the “largest” crater?
- Which created the deepest crater?
- Which stone falls the fastest?
- How can we test the fall of our stones so that the same thing can be examined for everyone?
Stage Debriefing Questions (Optional)
- What was difficult about working with the stones?
- When we let the stones fall, it was like a race! Did the heavy stone win the race, or did they land in the sand at the exact same time?
- Both stones landed at the same time, but look at the holes—why do you think the heavy one made a deeper ‘splat’ in the sand than the light one?
- If you look at our sandboxes and the pictures of the Moon, what do you see that looks the same?
- Can you spot any craters in our sand that look like the ones we saw in the pictures?
Tips and Tricks for dealing with stage challenges
- The temptation to “throw”: It’s a child’s natural instinct to throw the stones into the sand to see a big “splash,” rather than just dropping them. in this cae don’t present the rule as a “ban,” but rather as part of a story. Tell them that their hands are now a precise “landing craft” that must remain completely still when they release the stone so that the experiment is accurate.
- The embarrassing result: Children are often convinced that the heavier stone falls faster, and they are surprised (or even embarrassed) when they see that the heavy and light stones hit the ground at the same time. In this case don’t explain complicated laws of physics to them. Use this moment to spark their curiosity. Ask them, “Did you expect the heavier one to be faster? Why did this surprise us?” This will help them trust their own observations rather than their preconceived notions.
- Smoothing the Sand: Smoothing the surface of the sandbox after every single throw might seem like a bit of a tedious task for a 6-year-old. Inthis case we suggest to rename this step “preparing the landing site.” Tell them that every professional lunar explorer needs a clean, flat “landing site” so that the results of the next exciting experiment will be clearly visible.
- “Fluctuation” in the height of the throw: It can be difficult for children to release the rocks from exactly the same height every time, since their hands aren’t steady enough yet or they might not be paying attention. If one stone falls from a higher height than another, the experiment will no longer be “fair,” and the results will not be comparable. In such cases, mark a specific height using a tool that indicates where the stone should be dropped from. This gives the children a visual guide to follow, making it easier for them to work accurately.