Chromatic Aberrations in the Eye - Physics Demonstrations - Chromatic Aberrations in the Eye | Physics Undergraduate Labs

UV-A light (315-400 nm) can cause eye strain with prolonged direct viewing and potential skin effects with extended exposure. Limit demonstration to 2-3 minutes and instruct students to look at the tube but not stare continuously. The glass envelope absorbs most harmful UV-B and UV-C radiation, but UV-A still reaches observers.

Purpose

Demonstrates chromatic aberration in the human eye. Students observe a purple halo around a UV lamp that they cannot bring into sharp focus simultaneously with the blue tube — direct evidence that the eye has wavelength-dependent focal lengths.

UV fluorescent tube mounted vertically on a ring stand with parallel clamp. The aluminum case and power supply sit on the table beside it.

Figure 1: UV tube clamped vertically on ring stand, with the aluminum case removed and set aside.

Safety Warnings

Warning: UV Exposure Warning

Purpose