Ask: "How well can we see in the dark?" and "What sources of light help us to see at night?" Collect pupils' responses and then watch the clip. Afterwards, discuss how our eyes adjust to low-light conditions. Encourage children to stare at a bright window for 20 seconds and then to check the pupils of their eyes in a mirror. What do they see? Repeat the experiment, this time with children staring into a dark corner. The children should note their pupils expand in dark conditions. This allows more of the available light to enter their eyes, so they can see more clearly. Put some similarly coloured counters in a box. Cover the box with a blanket. Ask individuals to go under the blanket and tell you the colours they see. Afterwards, tip the counters out into the light. Is it harder to distinguish colours in low light conditions?