Figure 1

It is difficult for some students to understand that the real image is formed in space (air) regardless of whether it can be seen. The image of the slide with crossed lines is formed by the Kodak slide projector. The black, ribbed screen in front of the projector helps absorb and dissipate the light rays. Sharp or blurry real images are revealed by rapidly waving the white stick between the projector and the black screen.

List of parts:

1. Kodak slide projector
2. Slide with crossed lines
3. Black ribbed screen
4. White stick

Note: Lights should be dimmed in auditorium during the demonstration.