Explain how sonar and ultrasound imaging work

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Explain how sonar and ultrasound imaging work

• http//www.soundmetrics.com/

• Sonar
• (sound navigation and ranging)
• a. Distance to ocean floor D1/2vt
• b. organisms that use sonar bats, dolphins,
  whales

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ULTRASOUND IMAGING

• SONOGRAMS
• frequency of 1 million-15 million Hz
• A. MEDICAL USES OF
• a. diagnose problems
• b. guide surgical procedure
• c. view unborn fetuses
• B. NONMEDICAL USES OF
• a. locate hairline fractures in metal
  support beams and machinery
• b. clean jewelry, dentures, and small
  machinery
• 2. ADVANTAGE of ultra vs x-ray
• a. doesnt harm living cells

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Section 12.1 review questions

1. What is the human range of hearing?
2. Musical instruments produce ___waves?
3. What does harmonics do for instruments?
4. What does resonance do for instruments?

Medium Speed of sound m/s
Gases Air(0C)331
Air(25C) 346
Air(100C) 386
hydrogen(0C) 1290
Liquids Water 1490
Sea water 1530
solids Copper 3813
Iron 5000
Rubber 54
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Review for Ear

1. What is sonar?
2. Name 3 organisms that use sonar.
3. Give the formula used to determine depth using
   sonar.
4. What is a sonogram?
5. Name 5 medical uses of Sonar.
6. What is the advantage of sonar over x-rays?
7. Name 3 nonmedical uses of Sonar

• Try to sketch and label from memory the parts of
  the ear.
• Name the regions of the ear?
• Where does resonance occur in the ear?

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Recognize that light has both wave and particle
characteristics

• Wave characteristics
• a. 1801 Thomas Young
• interference pattern in light
  so modeled wave
• b. model supported by interference, reflection,
  and refraction

• Particle characteristics
• a. 1905 Albert Einstein explain photoelectric
  effect
• b. photons are bundles of energy which can eject
  elecrtons from a metal plate
• c. model is supported by dim blue light knocking
  electrons off a metal plate while bright red
  light cannot.
• d. Explains how light can travel without a medium

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Vision

• Accommodation
• the process by which the eyes lens changes shape
  to focus the image of objects on the retina
• Retina
• the light-sensitive inner surface of eye,
  containing the receptor rods and cones plus
  layers of neurons that begin the processing of
  visual information

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Vision

• Rods
• retinal receptors that detect black, white, and
  gray
• necessary for peripheral and twilight vision
• Cones
• receptor cells that are concentrated near the
  center of retina
• function in daylight or well-lit conditions
• detect fine detail and give rise to color
  sensation

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The Eye

• Optic Nerve nerve that carries neural impulses
  from the eye to the brain
• Blind Spot point at which the optic nerve leaves
  the eye, creating a blind spot because there
  are no receptor cells located there

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Vision
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Retinas Reaction to Light
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Vision--Receptors
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Pathways from the Eyes to the Visual Cortex
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Visual Information Processing
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Visual Information Processing

• Feature Detectors
• nerve cells in the brain that respond to specific
  features of the stimulus
• shape
• angle
• movement

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Visual Information Processing
Feature detection Brains detector cells respond
to elementary features-bars, edges, or gradients
of light
Abstraction Brains higher-level cells respond
to combined information from feature-detector
cells
Retinal processing Receptor rods
and cones?bipolar cells ? ganglion cells
Recognition Brain matches the constructed image
with stored images
Scene
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Visual Information Processing

• Young-Helmholtz Trichromatic (three color) Theory
• the retina contains three different retinal color
  receptors- one most sensitive to red, one to
  green, and one to blue- which when stimulated in
  combination can produce the perception of any
  color