The toy is still there. Will the detector spot it when the light gets dim?
Use a torch and a paper object. Change the light, then explain what changed and what stayed there.
Multiply each reading by the light fraction and compare with the detector boundary. Count misses and false spots separately.
Cut these cards apart. Use the original example first, then let a partner supply a changed case. Keep sealed/final cards with the teacher until the learner commits a rule.
Reading: 0.12
Toy present: False
My prediction and reason:
Reading: 0.72
Toy present: True
My prediction and reason:
Reading: 0.68
Toy present: True
My prediction and reason:
Reading: 0.8
Toy present: True
My prediction and reason:
Reading: 0.13
Toy present: False
My prediction and reason:
The readings are a teaching model, not a calibrated camera or real sensor.