Why does sound travel
faster in the ground than
air?
Knock on your desk.
Sound is a mechanical wave
Meaning it NEEDS a medium to travel through.
Sound is a mechanical wave
Meaning it NEEDS a medium to travel through.
The particles in solids can hit into each other more quickly, so the
sound travels faster.
Sound is a mechanical wave
Meaning it NEEDS a medium to travel through.
Solid needs to be stiff
like steel, not like
rubber.
Engineering and Sound?
Electromagnetic- Light
How are electromagnetic waves (light waves) different than
mechanical waves (sound waves)?
Electromagnetic- Light
How are electromagnetic waves (light waves) different than
mechanical waves (sound waves)?
They don’t need a medium!
The extra particles get in the way. When can
see when the speed of light has been changed.
Refraction
https://utah.pbslearningmedia.org/resource/lsps07.sci.phys.energy.lightref
ract/observing-refraction-of-light/#.WMffUTsrK00
Change in the direction of a wave due to a medium. This
changes the speed of the light.
Refraction
When light passes through a
prism the light bends. As a
result, the different colors
that make up white light
become separated. This
happens because each color
has a particular wavelength
and each wavelength bends at
a different angle.
This is why we have rainbows.
https://www.youtube.com/watch?v=OQSNhk5ICTI
Why we see colors
Different colors have different
wavelengths and frequencies. Reds
(infrared light) has big wavelengths
while purple (ultraviolet) has very short
wavelengths.
Why we see colors
Different colors have different
wavelengths and frequencies. Reds
(infrared light) has big wavelengths
while purple (ultraviolet) has very short
wavelengths.
Frequency and wavelength affect
color. What affects brightness?
Why we see colors
Different colors have different
wavelengths and frequencies. Reds
(infrared light) has big wavelengths
while purple (ultraviolet) has very short
wavelengths.
Frequency and wavelength affect
color. What affects brightness?
Higher the amplitude, the more
bright.
Reflection
Reflection- a wave
cannot travel through a
medium. The direction of
the wave is “bounced”
back into its original
medium.
Reflection
Reflection- a wave cannot
travel through or be
absorbed by a medium. The
direction of the wave is
“bounced” back into its
original medium.
REverberations- repeated echos
How does your eye work?
https://www.youtube.com/watch?v=fn6v3SkH0LI
https://www.youtube.com/watch?v=cFVbLnXWn6A
Mechanical waves
need mediums
Electromagnetic
travel better
without them.