Light can come from a natural or artificial source
We detect light with our eyes
EXAMPLE QUESTIONS
What do you think light is?
Where can light come from?
How do you think you would manage if there was no light?
What do you depend on light for?
THERE ARE MANY DIFFERENT SOURCES OF LIGHT
Light moves in all directions from the source that is creating the light (the sun or a light bulb, for example).
The sun is the main source of light for living things on earth.
Other sources of light include flames, incandescent materials (eg hot wires or hot ceramic mantels in gas lamps (and electricity travelling through air (as in lightning) or through a very low pressure gas (as in fluorescent lighting tubes).
EYES DETECT LIGHT
Eyes can detect different brightness and colors.
Light travels to the eyes and enters them through the pupils.
The iris controls the size of each pupil to let in more or less light.
The lens of an eye focuses the light onto the retina at the back of the eye.
Images of what the eyes are focusing on form on the retina, which contains sensitive receptor cells that convert the light into signals.
The signals travel, via the optic nerves, to the brain which interprets these signals.
