Whenever you play a guitar or play a piano or beat a
drum you hear certain frequencies of sound that
make the beautiful music you hear. However these
frequencies are very specific and do not change unless
you tighten the strings of your guitar, tune your piano,
or get a different drum. These specific sounds that we
hear are directly correlated to standing waves. So
what is a standing wave? A standing wave is
essentially a wave that has specific wavelengths it is
confined to based on the length of its confinement. A
guitar string for example is bound by the length of the
guitar. The reason why you hear specific frequencies
of sound from the guitar is that the guitar string can
only vibrate at frequencies with the corresponding
integer wavelength that it is bound to.
http://www.physicsclassroom.com/class/sound/Lesson-5/GuitarStrings
We call these frequencies the resonant frequencies of
the guitar string. As you can see from the diagram
above there are different harmonics depending on
the frequency of the sound. Since the wavelength
and frequency of a wave are proportional to the
speed at which it propagates, 𝑐𝑐 = λ𝑓𝑓, where λ is the
wavelength, f is the frequency, and c is the speed at
which it travels. That’s why we are able to tighten
the strings to make higher pitched sounds, tightening
the string increases the speed at which it travels
therefore increasing the frequency making a smaller
integer of the wavelength. The drum in this
experiment utilizes the same principle however
instead of us playing the drum and hearing its
resonant frequencies, we are going to blast it with
sound at it resonant frequencies so that we can
capture it with a strobe light and observe the
outcome.
http://www.play-acoustic-guitar.com/acoustic-guitar-strings.html
Guitars utilizes standing waves by producing specific
frequencies of sound defined by the length of the
guitar string. That’s why when the guitar string
tightens the speed at which it vibrates when plucked
increases therefore the sound we hear is a higher
pitch because the sound created is of a higher
frequency.
Pianos also utilize
standing waves to
produce specific
frequencies of sound
instead of a string being
plucked however a
hammer delivers the
force to the string.
https://www.roblox.com/games/233727153/Piano-Keyboard-v1-1
http://physics.info/waves-standing/
http://www.physicsclassroom.com/class/sound/Lesson4/Standing-Wave-Patterns
https://www.physics.utoronto.ca/~jharlow/teaching/ev
eryday06/reading12.pdf
http://physics.bu.edu/~duffy/py105/Music.html
https://www.khanacademy.org/science/physics/mecha
nical-waves-and-sound/standing-waves/v/standingwaves-on-strings
Pamphlet written by: Kyser Seaney For more information,
contact Prof. Michael Grubb at 970-247-7238.
While this demo is not very home friendly we will still go into detail on how this demo works. So we
know that we shoot sound at the drum at these specific frequencies to excite the resonant frequencies
of the drum, or the sound frequencies for which we hear. However these frequencies are much too fast
for the eye to see which is why when a drum is struck we cannot actually see these resonant
frequencies. So how do we “slow” the drum down in order to see these frequencies? Well all we have to
do is set a strobe light at the frequency at which our eye can see and offset from the frequency of the
sound. An analogy to this would be movie film a bunch of pictures that are put together and played
at a specific frame per second allows us to view a bunch of pictures as if we were watching the movie.
Electrons orbit the nucleus of an atom at specific
energy levels, these energy levels we classify as
atomic orbitals. There are three main types of
atomic orbitals we will be discussing s, p, d. This
experiment utilizes the fundamental principle of
standing waves to model these orbitals on a latex
drum. Think of specific energy levels being
analogous to specific frequencies. The drum can
vibrate at various frequencies that are bound by
the circumference of the drum. If the right
frequency of sound is played at the drum it will
vibrate at this resonant frequency. Since the S
orbital is the lowest energy of the atomic orbitals,
the first resonant frequency of the drum i.e. the
lowest resonant frequency of the drum should
model that of an S orbital where the entire drum
will raise and lower as one piece. The next highest
energy orbital would be p so the drum should
have a resonant vibration like the picture below.
As the strobe light continues to flash at this frequency it will capture the entire wave at a frequency
which we can see, which will allow us to see the awesome shapes that represent the atomic orbitals!
With the power of science we can successfully make a physical model of something that would otherwise
be impossible to see that only exists in theoretical models. Below are the drum shapes that will hopefully
be shown in the demo. Hopefully you have enjoyed this demo!
http://blog.soton.ac.uk/soundwaves/standing-waves/3-membrane-modes/
http://graphitefurnace.blogs.com/main/2004/02/standing_waves.
html