Emit their own light — the Sun, stars, fire, lightning, some animals.
Don't emit light — the Moon only reflects sunlight falling on it.
Almost all light passes through — glass.
Only some light passes through — tracing paper.
No light passes through — cardboard.
A light source, an opaque object, and a screen — all three are needed.
Closer to the light, the shadow grows bigger; closer to the screen, it grows smaller and sharper.
Matches the object exactly.
Upright, not upside down.
Cannot be caught on a screen.
Left and right are swapped.
Two mirrors in a Z-shaped tube let you see around a corner — used in submarines and tanks.
Three mirrors in a triangle create repeating patterns through multiple reflections.
Emits its own light / does not.
Full / partial / no light passes through.
Dark patch where an opaque object blocks light.
Change in light's direction off a shiny surface.
An upright, non-inverted image.
Left-right reversal in a mirror image.
Forms an inverted image via a tiny hole.
See around corners / view repeating patterns.