Page 97 - Science Course 3 (Book 2)

Mo10-L6c: How Does the Human Eye Work?

The Colors of Objects The appearance of an object changes under different
colors of light.
The color of an object depends on the wavelengths
of the light waves it ref ects.
Ultraviolet Ultraviolet
An object absorbs some light waves and ref ects (UV) (UV)
others.

When light waves enter your eye, they cause the 400 nm 500 nm 600 nm 700 nm
cone cells in your retina to send certain nerve signals
to your brain. Wavelength of visible light in nanometers(nm)

These signals cause you to see colors.
Key Concept

How Does the Human Eye Work?
White Light
Why do you experience the sensation of color?
All colors
are ref ected

Red Light
Red color is
ref ected
White Light

No color is
ref ected

Green Light
Green color
is ref ected

A red rose ref ects SUMMARY
light waves with
wavelengths that you How Does the Human Eye Work?
see as red. It absorbs
all other wavelengths The eye has different parts with different
of light. functions. The iris is the colored part of your
eye. The iris opens and closes to control the
A banana ref ects light amount of light that enters the eye.
waves with wave-
lengths that you see
as yellow. It absorbs
all other wavelengths
of light.

The color of an object that emits light depends on
the wavelengths of the light waves it emits.

Light that you see as white is actually a combination
of light waves of many different wavelengths.
Iris
Pupil

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