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Youuse themall day, everyday.Youmay takeyour
sensesof sight, hearing, smell, tasteand touch for
granted, but eachone followsacomplexprocess
beforeconveying information toourbrains.
The studyof thefive senses canbe tracedback to the
GreekphilosopherAristotle.Thousandsof years later,
scientistsnowknow that themost developed sense
is sight, followedbyhearing.Let’s investigate these
first, followedby touch, tasteand smell.
Meet the five senses!
Colorblindness
Color blindness is the inability
todistinguishbetween
certain colors,mostly red
and green. Peoplewho
are color blind lack a
color-sensitivepigment
in the cone cells in the
retina. Color blindness is
twice as common inmen
thanwomen, as it is often
the result of genetics.
Sight
Your sense of sight helps you to
identifyyour friends, catch a baseball
and selectwhat color shirt youwant
towear. But how do your eyes
actuallywork?
Light passes through the cornea, or
the transparent surface of your eye, to
the pupil (the black opening). The size
of the pupil changes to regulate the
amount of light that enters the eye—
kindof like opening or closing the
shades on awindow.When an eye
doctor dilates your eyes for an exam,
he or she is enlargingyour pupils to
better see inside your eye.
The colored part of your eye around
your pupil is the iris.When people ask
about your eye color, they are referring
toyour iris.What color are your eyes?
After passing through the pupil, light
and imagesmove to the lens at the
front of your eye, which changes shape
to focus objects at different distances.
Light is bent and refracted (changed in
direction) as itmoves through the lens.
When you look at anobject up close,
light rays bendmore to focus on the
object.Viewing objects at a distance
requires less bendingof the light rays.
At the back of your eye is the retina,
which has two types of cells: rods and
cones. The rods enable sight in the
dark, while the cones help us to see
colors.As images are processed,
information is sent to the brain through
the optic nerve. The images are sent
toour brain upside down and then
reversed, similar to afilm camera.
Do you see anumber in the circle?
If not, youmay be color blind.
1 3,4,5,6,7,8
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