Factual series explaining all the mysteries of the world of science in BSL! In this episode, Professor Knowitall and his sidekicks Dr Spark and Dr Bright tell us all about light. How long does it take the sun's light to travel to Earth? Which is faster, light or sound? Dr Spark once again gets in the teleporter and blows up some watermelons to give us the definitive answer! Later, she's sent to a laser pointer to show whether light rays are curved or not. Finally, Dr Knowitall explores what happens when light is filtered through different colours.