Experimented with light going through the atmosphere. Used water instead of atmosphere and added milk to water to represent particles in the atmosphere. Shining through the water with a bright LED lamp in a dark room we observed how the light sensor reacted. If the atmosphere is clear (in clear water) light travels in a straight line, so the light sensor doesn’t react if the lamp is placed on the side of the plastic cup. But if the atmosphere is full of particles light is scattered in various directions and the reading on the light sensor is lower when shining straight down on it. The light sensor reacts when the lamp is placed on the side of the plastic cup.
Simon was so happy to see it worked. He had looked up this experiment in a LittleBits projects pdf booklet online and modified the circuit as we didn’t have all the necessary bits.