Refraction of Light at an Air‑Water Interface

Overview

A concise visual demonstration of a single light ray moving from air into water, illustrating how the ray bends toward the normal. The animation highlights the boundary, normal line, incident ray, refracted ray, and the angles of incidence and refraction, using small neat labels.

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Phases

#	Phase Name	Duration	Description
1	Setup	~4 s	The air‑water boundary line appears at the centre of the screen, followed by a faint normal line (perpendicular to the boundary). Small labels "Boundary" and "Normal" fade in beside them.
2	Incident Ray	~5 s	A single ray emerges from the left side of the screen, traveling toward the boundary at a chosen angle (≈45°). The ray is drawn gradually, and a tiny label "Incident Ray" follows the line.
3	Refraction Event	~6 s	As the incident ray reaches the boundary, it pauses, then a refracted ray sprouts on the water side, bending toward the normal (≈30°). The transition is smooth to emphasize the change in direction. A label "Refracted Ray" appears beside the new ray.
4	Angle Illustration	~7 s	Two arc markers are drawn: one on the air side for the angle of incidence (θ₁) and one on the water side for the angle of refraction (θ₂). Small labels "θ₁" and "θ₂" are placed next to the arcs. The arcs fade in, stay visible for a moment, then fade out.
5	Outro	~4 s	All elements (rays, arcs, labels) fade out, leaving only the plain background.

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Layout

┌───────────────────────────────────────┐
│               FULL SCREEN               │
│   (central diagram: boundary, normal,   │
│    incident & refracted rays, angles)   │
└───────────────────────────────────────┘

Area Descriptions

Area	Content	Notes
Full Screen	Central diagram containing the boundary line, normal line, incident ray, refracted ray, angle arcs, and tiny labels.	All visual elements are centred; background is plain white (or black if preferred).

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Notes

• Background should remain plain (white by default; black optional via a simple colour switch). No subtitles, captions, or large text blocks are used.
• Labels are kept small, placed just off the corresponding ray or arc to avoid covering the diagram.
• The animation speed is deliberately slow to allow class‑10 students to follow each step clearly.
• Total runtime is approximately 26 seconds, well within the 30‑second guideline.
• Only one Manim Scene class will be needed to implement this specification.