how do we know which place is the light source based on shadows?
Answers
Answer:
These light rays travel in a straight line at nearly 300,000 kilometres per second. Sunlight that travels towards the Earth takes just over 8 minutes to reach us. When the rays reach Earth, they hit whatever is in their path. If the object they hit is opaque, the light cannot pass through, and a shadow forms.
Simply speaking, a shadow is an absence of light. If light cannot get through an object, the surface on the other side of that object (for example, the ground or a wall) will have less light reaching it.
A shadow is not a reflection, even though it is often the same shape as the object.
Objects and shadows
The shape of the object determines the shape of the shadow. By looking carefully at the shadow, we can observe that the person on the right is dressed in shorts and is standing on one foot.
Light sources and shadows
There are many sources of light – stars like our Sun, candle flames, light bulbs, glow-worms and computer screens produce light. All of this light travels in a straight line until it hits something. Sometimes, it travels a short distance – like when we switch on the lamp. Other times, light travels thousands of years – like the light from stars we see in the Milky Way.