- Chemical Reactions
Students use various objects to make patterns on light-sensitive paper.
Have you ever noticed that curtains or furniture will fade if they are exposed to sunshine? The sun's rays can cause material to change.
Light-sensitive paper is a special type of paper which is very sensitive to the sun's rays. When light hits it, a chemical named Berlin green in the paper reacts with the sunlight to produce a new chemical named Prussian blue. Putting objects on top of the paper prevents the light from reaching those areas, so no reaction takes place. when the paper is placed in water, any remaining Berlin green is washed away. But the Prussian blue that was produced where sunlight hit is not water soluble so it stays in place.