our senses chapter 8.2. it is true that when you look at a rainbow, the wavelength of light...
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Light Electromagnetic energy –Described in wavelengths –Not all light is visible to humans –Wavelengths can be a fraction of an inch to miles long (cosmic- radio)TRANSCRIPT
Our Senses
Chapter 8.2
• It is TRUE that when you look at a rainbow, the wavelength of light determines the colors you see– Red wavelength is longer than orange &
continues to get shorter until violet which has the shortest wavelength
Light
• Electromagnetic energy– Described in
wavelengths– Not all light is visible to
humans– Wavelengths can be a
fraction of an inch to miles long (cosmic-radio)
The Eye• Similar to a camera• Amt. of light that enters
is determined by opening of the colored part of eye– Blk. area is pupil– Pupil size is sensitive to
our emotions• Light then encounters
the lens; adjusts to the distance of objects by changing its thickness– Squinting is people
adjusting their lenses
• The changed image is projected onto the retina– Like the film in camera; neurons that are
sensitive to light (photoreceptors) carries the input to the brain
– Information is relayed to visual area of brain• Blind Spot
– We all have one, area of eye where there are no photoreceptors
• Rods & Cones– Rods-sensitive to
brightness– Cones-provide color
vision• Adaptation
– May take time for eyes to adjust to a dark room
– Adaptation to bright light happens more quickly
• Visual Acuity– Sharpness of vision– Ability to see visual
details
Color Vision • People with normal color vision see any color in the spectrum of visible light
• When one color stimulates the cones, we perceive more colors
• Color Blindness; people who do not have normal color vision– Malfunction of cones
Hearing
• Hearing depends on the vibrations of the air (known as sound waves)– Once the sound waves
hit the ear, tiny hair cells move back & forth
– Hair cells then change sound vibrations into neuronal signals that go to the brain
• Loudness=amplitude (or height) of sound– Measured in decibels
• Normal range of hearing is from 0-140 decibels– Damage can be done
to your ear @ 110 decibels
• Look on website info.http://www.centerpointaudio.com/
Earbud-Safety.aspx
How we hear sound
• Watch the short video about how we hear:
Deafness
• 2 Types– Conduction; when
there is a hindrance of physical motion through the outer/middle ear OR damage to the bones
– Hearing aid can help
• Sensor neural– Damage to the
cochlea, the hair cells or auditory neurons
– Need a cochlear implant to help
Balance
• Sense of balance is regulated by the inner ear
• Overstimulation can cause dizziness & motion sickness
Smell & Taste
• Check back here!• We’ll be doing an
experiment over smell & taste on Tuesday