Physics · Grades 1–3
Light, seeing and shadows
Follow light from a source to an object and understand blocked light.
Learn the idea
Seeing an object
Light from a source can reflect from an object into our eyes. Ordinary objects are not all light sources.
Shadow
An opaque object blocks some light. The dark region beyond it is a shadow, not a substance coming out of the object.
Materials
Transparent materials pass much light; translucent materials scatter transmitted light; opaque materials block transmission.
Safe observations
Use normal room light or a torch aimed away from eyes. Never look at the Sun or shine bright beams into eyes.
Worked examples
Which item normally produces its own visible light when switched on?
A working torch is a light source; the ruler and book are normally seen by reflected light.
A torch
What makes a shadow behind an opaque card?
A shadow is a region reached by less direct light.
The card blocks some light.
Check your understanding
Which sequence explains seeing a red book in a lit room?
- Eye → book → lamp
- Book → gravity → eye
- Lamp → book → eye
Which material usually lets you see a clear image through it?
- Thick cardboard
- Clear window glass
- A wooden board
Explain why a shadow can move even when the object stays still.
Answers and marking notes
Answers and marking notes
- Lamp → book → eye
Light illuminates the book and some reflected light reaches the eye.
- Clear window glass
Clear glass transmits visible light with relatively little scattering.
- The light source can move, changing which paths are blocked.
Accept a change in source position or direction with a coherent explanation.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.