Screen-free play
Shadow Size Experiment
Why Shadow Size Experiment works
At its simplest, Shadow Size Experiment is about prediction, fair comparison, and evidence-based conclusions, starting with the instruction to place one object where it casts a clear shadow. Change the distance between an object and a light source to observe how shadow size changes. The first useful comparison appears when the child then has to observe the first shadow size.
Set up — Place one object where it casts a clear shadow
Prepare household items before the child is asked to place one object where it casts a clear shadow. Complete the opening request to place one object where it casts a clear shadow once before adding the next instruction to observe the first shadow size. Use household-safe materials and keep the setup stable, supervised, and easy to clean up throughout that first transition.
Step 2 — Observe the first shadow size
Allow room for a mistake while the child tries to observe the first shadow size. A self-correction here is more useful than fast repetition before the child moves on to move the object closer to or farther from the adult-controlled light.
Step 3 — Move the object closer to or farther from the adult-controlled light
After the child tries to move the object closer to or farther from the adult-controlled light, ask one brief question about the result. Connect their answer to the next request to observe the new shadow rather than explaining it for them.
Step 4 — Observe the new shadow
Have the child observe the new shadow before offering a solution. What happens here should help them understand how to repeat once and describe the relationship, especially compared with the earlier request to move the object closer to or farther from the adult-controlled light.
Step 5 — Repeat once and describe the relationship
Give the child time to repeat once and describe the relationship and notice the result. The following instruction to repeat once and describe the relationship should use what they learned after previously trying to observe the new shadow.
What to notice before Repeat once and describe the relationship
The strongest evidence appears after the child has tried to move the object closer to or farther from the adult-controlled light and before they finish by trying to repeat once and describe the relationship. Look for what changes when one condition changes and what stays the same rather than judging the round by speed or neatness.
Make Move the object closer to or farther… easier or harder
Use the child’s last successful attempt to move the object closer to or farther from the adult-controlled light to set the next round. Simplify by doing this: run one clear comparison with obvious conditions. Extend it by doing this: repeat the test, measure more carefully, or change one variable only.
Finish after Repeat once and describe the relationship
Finish on the clear result that comes from asking the child to repeat once and describe the relationship. If they understand how it follows from move the object closer to or farther from the adult-controlled light, the activity has done enough; use the activity search or activity generator next.
What you need
- Household Items
How to play
- Fix the light source and mark one straight line between the light and the wall or screen.
- Place the object on the line and record the first shadow size.
- Move the object closer to the light without shifting it sideways and compare the new shadow size.
- Move the object farther from the light on the same line and compare again.
- Describe the relationship between distance from the light and shadow size.
Make it easier
In Shadow Size Experiment, for the first attempt, treat the first two actions as the whole round. Keep “Fix the light source and mark one straight line between the light and the wall or screen.” and “Place the object on the line and record the first shadow size.” Once those two actions are clear, the easier version is complete.
Make it harder
For a more independent round, let the child decide when the middle step is complete. The step that stays central is “Move the object closer to the light without shifting it sideways and compare the new shadow size.” Do not add speed or competition.
Play together
In Shadow Size Experiment, for two people, let the first person handle the opening step and the second person handle the middle step. Use “Fix the light source and mark one straight line between the light and the wall or screen.” as the opening job and “Move the object closer to the light without shifting it sideways and compare the new shadow size.” as the handoff point. In Shadow Size Experiment, the role change is the only variation needed.
Two or more kids
In Shadow Size Experiment, for a group version, use separate setup, action and checking roles. Keep “Describe the relationship between distance from the light and shadow size.” as the common finish. In Shadow Size Experiment, the result belongs to the group, not to one winner.
Skills practised
Comparison, Experimental Thinking, Observation, Prediction
Safety
Use daylight or an adult-controlled cool flashlight kept outside the child's working area. No candles, hot lamps, reachable cords, loose batteries or mains-powered equipment in the child's hands.
Supervision: Direct