Rainbow becomes white light

Put together the experiment shown in the diagram. Again, use a bendable plastic mirror strip as a dish mirror. Answer the questions.

Separating white light into a spectrum and recombining it into white light

Instructions for the experiment

The most technical trick of the experiment is to bend the mirror so that the reflected light falls on the screen. The first step is to direct the reflected spectrum from the flat mirror onto the screen. Once this reflection has been found, we can start to carefully bend the mirror, while observing how the reflected spectrum narrows. Eventually, it becomes a white dash.

To bend the mirror, attach larger paper clips to the ends of the mirror and bend it by holding them. This will ensure that the bending of the mirror shape is close enough to the shape of a circle. If the white stripe has coloured edges, we need to adjust the way the mirror is bent.

The rainbow becomes white light again