A shadow forms where an object blocks light. Light spreads out from a small lamp. Move the same object nearer the lamp and its shadow on the screen gets bigger. Move it nearer the screen and the shadow gets smaller. Follow the straight rays past the object’s edges to see why. The object itself keeps the same height.
Light, sound and electricity · Discover & try
What makes a shadow bigger?
Reading level 1 of 5 · EarlyChange
Word help
opaque
Not letting the model light pass through.
ray
A line representing the direction light travels.
Watch · Try · Explain
See how it works
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Point-source projection; sharp edges and distances are idealised, not a real lamp measurement.
What to look for
- Edge rays continue straight
- The object keeps its own size
- A closer object makes a wider projection
Explain what you noticed
A fixed screen is 6 units from a point lamp. A 1-unit object moves from 3 units to 2 units from the lamp. What happens?
Keep this idea: A shadow can change size without its object changing size.
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Source material checked 2026-10-29. Explanations and activities by Nepedia. Source links do not imply endorsement.
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