🌈 Rainbow Mindmap — Light & Shadows
Seven quick points (one per rainbow colour). Use as central nodes for your visual mindmap.
1
Light travels in straight lines
Evidence: torch beam, pinhole, shadows — rectilinear propagation explains many effects.
2
Shadow formation
Opaque objects block light → region behind object receives less/no light → shadow forms.
3
Umbra & Penumbra
Umbra = fully dark central shadow; Penumbra = partial/light shadow at the edges.
4
Solar eclipse
Moon comes between Sun and Earth → Sun (part/whole) is hidden → happens at new moon (umbra/penumbra visible).
5
Lunar eclipse
Earth comes between Sun and Moon → Earth’s shadow falls on Moon → visible at full moon (umbra/penumbra).
6
Pinhole camera — principle & working
Principle: rectilinear propagation. Construction: dark box, tiny hole, screen. Image: real, inverted.
7
Factors affecting image size
Image size depends on: object-to-hole distance, hole-to-screen distance, and object size (closer → larger).
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