A small spotlight like a cellphone torch forms a more distinct shadow than an overhead room light, but the sharpness of the shadow changes when the torch moves away from the object.įrom our vantage point on Earth, it appears that the Sun moves across the sky during the day. The size of the light source can sharpen or blur the shadow. Shadows are also more definite (sharper) where there is contrast between the shadow and the lit surface, for example, a shadow on a white wall will be more easily seen. It is easy to see our shadows when we are outdoors in the sunshine on a clear, bright sunny day, but do shadows form when an object blocks light from other sources? The answer is yes, but they may be difficult to see if the light source is not very bright (has a low light intensity). Other times, light travels thousands of years – like the light from stars we see in the Milky Way. Sometimes, it travels a short distance – like when we switch on the lamp.
All of this light travels in a straight line until it hits something. There are many sources of light – stars like our Sun, candle flames, light bulbs, glow-worms and computer screens produce light.
