Shadows are evidence of light travelling in straight lines. An object blocks light so that it can’t reach the surface where we see the shadow. Light fills up all of the space before it hits the object, but the area between the object and the surface is in shadow. Shadows don’t always appear totally dark because there is still some light reaching the surface that has been reflected off other objects.
The shape of a shadow matches the object casting it, but the size and definition (blur) can change depending how close or far away the source of light is. Try moving a torch closer and further away from an object.
You can also tell from the shadow where the light source is. Look at these lipsticks below, Where would the light source be?
Fun with shadows
With at least one friend stand near each other and try and create a wacky shadow on the playground floor. Can it have 2 heads - 4 arms, 3 legs....... Be creative!
There are lots of websites that teach how to make shadow puppets or use your hands to make shadow animals.