Chapter #12
Sound and Light
Decibels (dB) units
used to measure
sound intensity.
Infrasound any
sound consisting
of waves with
frequencies lower
than 20 Hz.
Ultrasound any
sound consisting
of waves with
frequencies
higher than 20
000 Hz.
Chapter 12.1 Notes
• Resonance an effect in which the vibration
of one object causes the vibration of
another object at a natural frequency.
• Pitch the perceived highness or lowness of
a sound, depending on the frequency of
sound waves.
• Sonar (sound navigation and ranging) a
system that uses reflected sound waves to
determine the distance to, and location of,
objects.
Sound waves are transmitted as vibrations
into the ear and they bounce into the
eardrum. Vibrations are then passed to the
3 bones and then transferred to the
cochlea and to the auditory nerve.
Chapter 12.2 Notes
• Photon a particle of light.
• Intensity the rate at which light or any
other form of energy flows through a given
area of space.
• Radar a system that uses reflected radio
waves to determine the distance to, and
location of, objects.
• Radar stands for Radio Detection And
Ranging
• Light can act as a
wave or a
particle.
• Electromagnetic
spectrum- is the
full range of light
at different
frequencies.
Chapter 12.3 Notes
• Light ray a model of light that represents
light traveling through space in an
imaginary straight line.
• Reflection is the bouncing off a light wave.
• Law of reflection states “The angle of
incidence equals the angle of reflection”
Virtual image an image that forms at a point
from which light rays appear to come but do
not actually come from.
Real image an image of an object formed by
many light rays coming together in a specific
location.
• Colors are able to be seen because light is
reflected back to your eyes.
Chapter 12.4 Notes
Refraction- the bending of light waves when
they pass from one medium to another.
Refraction makes objects appear to be in
different positions.
Refraction in the atmosphere creates mirages.
Mirage is a virtual image caused by refraction
of light in the atmosphere. (looks like there
is water on the road).
• Total internal reflection the complete
reflection of light at the boundary between
two transparent mediums when the angle
of incident exceeds the critical angle.
So the 60* angle has total internal reflection
• Lens is a transparent object that refracts
light rays, causing them to converge or
diverge to create an image.
• Magnification a change in the size of an
image compared with the size of an object.
• Prism is a transparent block with a
triangular cross section.
• Dispersion is an effect in which white light
separates into its component colors.
• Sunlight is dispersed and internally
reflected by water droplets to form a
rainbow.
Work Cited
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“Sound wave”. May 8, 2008. http://www.privateline.com/TelephoneHistory/speech.jpg
“Decibel levels”. May 8, 2008. http://www.itap.purdue.edu/images/candy/hearingChart.jpg
“Cartoon”. May 8, 2008. http://imgs.xkcd.com/comics/resonance.png
“The Ear”. May 8, 2008.
http://www.infj.ulst.ac.uk/~pnic/HumanEar/Andy's%20Stuff/MScProject/workingcode_Local/human
ear.jpg
“Bus reflected image”. May 12, 2008. http://www.oxford-chiltern-buspage.co.uk/upload121003/OX827-reflected-at-Water-Eaton.JPG
“Leaf with color reflection”. May 12, 2008.
http://www.shortcourses.com/images/b4ch4/greenobject.jpg
“Glass of water”. May 13, 2008.
http://webphysics.davidson.edu/faculty/dmb/EdibleOpticalMaterials/glass_of_water.jpg
“Beaker with penny inside”. May 13, 2008.
http://www.bbc.co.uk/schools/ks3bitesize/science/images/sci_dia_97.gif
“Total internal reflection”. May 13, 2008. http://www.timbercon.com/Fiber-OpticGlossary/images/Total-Internal-Reflection.gif
“Lens”. May 13, 2008. http://www.abledata.com/product_images/images/02A0587.jpg
“Prism”. May 13, 2008. http://cache.eb.com/eb/image?id=7710&rendTypeId=4
“Rainbow on blue sky”. May 13, 2008.
http://www.eaas.co.uk/images/atmospheric_optics/rainbow.jpg
“rainbow over tree”. May 13, 2008. http://www.entheosweb.com/images/photoshop/rainbow_6.jpg