Convex Lens - Physics Demonstrations - Convex Lens | Physics Undergraduate Labs

Ensure all electrical connections are secure and power strips are positioned away from traffic areas. Incandescent lamps become hot during operation; allow cooling time before handling.

Purpose

Demonstrates real image formation with a convex lens and directly addresses the common misconception that different parts of a lens form different parts of the image. Blocking half the lens dims the image but does not remove any portion of it.

Large convex lens clamped to a vertical rod on the lecture bench with a gray mounting plate, two illuminated desk lamps on a wooden stool positioned below

Same setup with a piece of white cardboard blocking approximately half the convex lens aperture

Figure 1: Convex lens clamped at the front of the lecture bench, with two lamps on a tall stool positioned to project filament images onto a screen or wall.

Figure 2: Blocking half the lens with cardboard. The complete image remains visible on the screen, but dimmer.

Safety Warnings

Warning: Electrical Safety

Purpose