Upcoming Deadlines Homework #9 – Stop-motion Character Animation Due Wednesday, November 3 rd (This Wednesday) 10 points (5 points if late) Homework #10 – Outline for Second Term Paper Due Wednesday, November 10 th (Wednesday of next week) 10 points (5 points if late) Second Term Paper – Science Fact or Cinematic Fiction? Due Wednesday, November 17 th 100 points (50 points if late) For full schedule, visit course website: ArtPhysics123.pbworks.com Pick up a clicker, find the right channel, and enter Student ID
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Upcoming Deadlines Homework #9 – Stop-motion Character Animation Due Wednesday, November 3 rd (This Wednesday) 10 points (5 points if late) Homework #10.
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Upcoming Deadlines
Homework #9 – Stop-motion Character AnimationDue Wednesday, November 3rd (This Wednesday)10 points (5 points if late)
Homework #10 – Outline for Second Term PaperDue Wednesday, November 10th (Wednesday of next week)10 points (5 points if late)
Second Term Paper – Science Fact or Cinematic Fiction?Due Wednesday, November 17th 100 points (50 points if late)
For full schedule, visit course website:ArtPhysics123.pbworks.com
Pick up a clicker, find the right channel, and enter Student ID
Special Guest Animation JudgeThe top three stop-motion character animations (this Wednesday’s homework) will be picked by Jason Spencer Galsworthy of Dreamworks Animation (and formerly with Aardman Animation).
Homework Assignment #10
Outline of your Second Term Paper.Topic: Science Fact or Cinematic Fiction?
An important component of being a well-educated adult is the ability to distinguish between fact and fiction, between science and make-believe.
For this assignment, you will choose a single physics principle, such as conservation of energy or the action/reaction principle, and describe three scenes from three different films that incorrectly illustrate that physics law or principle.
Homework Assignment #10
For example, you can describe how the principle of action/reaction is violated during a fight sequence when one character recoils but without a matching reaction on the other character.
The three films you select can be animated or live-action featuring CGI animation special effects.
You are strongly encouraged to find three scenes that are as different as possible from each other yet have the same fundamental error in the physics.
Homework Assignment #10
Post your outline in a blog entry entitled, “Outline for the Second Term Paper.”
Outline due by 8am on Wednesday, Nov. 10th
10 points (if late, 5 points)
The term paper itself is due a week later. Length, structure, grading rubric, etc. are similar to
the first term paper.
Activating your Clicker* Turn on your clicker.* Enter the channel number or letter for
joining this class. Hit Enter/Send key.* Clicker should read AP123GF10* Type in your student ID; hit
Enter/Send.Clicker is now ready to use; leave it on.Hit any key to wake the clicker from sleep mode.
Survey Question
You attended the “Animation Show of Shows” last Friday evening.
True or False
Review Question
Synchronized standing and sitting by a stadium’s crowd is what type of wave?
When a buzzer is moving towards you the wavelength of the sound gets shorter.
The frequency of the sound is…
a) Higher b) Lower c) UnchangedShorter Wavelength
Doppler Effect
a)Higher
If moving towards you, wavelength shorter and frequency higher.
If moving away, wavelength longer and frequency lower.
Waves & SoundPart II
“Talkies”
The first feature film with synchronized sound, 1927’s The Jazz Singer, was made using Vitaphone, a sound-on-disc technology.
Sound-on-film, however, would soon become the standard for “talkies”by the early 1930s.
Sound-on-film sound track
Silly Symphonies
Silly Symphonies had many imitators, including Warner Bros.’s Looney Tunes and Merrie Melodies, as well as MGM's Happy Harmonies.
From 1929 to 1939, Disney studios created 75 cartoons in the Silly Symphonies series, starting with The Skeleton Dance.
This series dominated the Oscars, winning yearly from 1932 to 1937.
The Skeleton Dance (1929)
http://www.youtube.com/watch?v=jkhxjzc9uuE
South Park: Bigger, Longer & Uncut (1999)Disney (and the rest of the industry) believed that audiences would not sit through a feature-length animated feature with simplistic animation.
http://www.youtube.com/watch?v=6UMaTg3lSf4
South Park proved him wrong, making over $82 million worldwide, with a $21 million budget.Was it the catchy music?
Frequency & Pitch
The faster vibrations, have higher frequency. Higher frequencies results in higher pitch for the musical note.
Musical notes are sound waves of different frequencies.
Standing WavesWhen a wave
interferes with its reflection, this may create a standing wave.
Fundamental & OvertonesThe Fundamental is the lowest frequency standing wave.The Overtones are twice, three times, etc., the frequency of the Fundamental.
110 Hz (A2)
220 Hz (A3)
330 Hz (E4)
Frequencies of standing waves for a 6 foot long organ pipe
OctaveThe note produced by two strings, one half
the length of the other, sounded similar.In Western music these two notes are said to
be an octave apart.Higher note is twice the frequency of the
lower.
Sing “Some-where over the rainbow…”
Men and women typically sing an octave apart.
C5
C4
Perfect Fifth
If the second string is 2/3rd the length
then the two notes are said to be “a fifth apart.”
Higher note has 50% higher frequency.
G4
C4
Separation between tenor and bass or soprano and alto.
Sing “Twin-kle, twin-kle little star…”
Strings and PipesShorter the string or the pipe, the higher the frequency of the note that’s produced.
Brass InstrumentsResonant standing waves produced in a pipe (horn); the set of frequencies (notes) depends on the length of the pipe.
Valves used to vary the length through in pipe
Woodwind InstrumentsResonant standing waves also produced in a pipe but the pipe length varied by air holes (finger-holes, keys, or pads).
Flute
Clarinet
Saxophone
Oboe
Bassoon
Meter stick
Cor anglais
Demo: Playing a Straw
Can make a simple reed by cutting a straw, as shown, lightly placing it between your lips, and blowing hard.
What happens if you shorten the straw (e.g., cut it in half)?
Demo: Hoot TubesLarge tube has a metal screen near one
end.Heat screen with a flame.
Remove tube from the flame and it
plays like an organ pipe.
The sound created by the larger hoot tube has a larger:A) Frequency; B) Wavelength; C) Amplitude
Hoot Tubes, Analyzed
C) Amplitude.Remove the flame and hot
air rises from the screen, drawing in cold air.
Hot air rising through pipe causes vibration at natural frequency, which depends on the length of the pipe.
Amplitude depends on the diameter of the pipe.
FLAME
Natural FrequenciesMetal baseball bat
and wooden bat sound very different when dropped to the floor.
Different materials and shapes vibrate at their own natural frequencies.
Forced VibrationsVibrating guitar strings force the vibration
of the guitar’s body, producing the sound.
553 Hz 731 Hz
Circular rings indicate where the surface vibrates up and down
Demo: Tuning Fork & Sound Box
Tuning fork by itself is not very loud.
Sound is much louder if it is held against a sound box, such as the body of a guitar or any similar rigid surface.
The tuning fork forces the surface into oscillation at the same frequency.
ResonanceResonance occurs when forced vibrations match an
object’s natural frequency.
Oscillations grow in amplitude due to synchronized transfer of energy into the vibrating object.
Acoustic ResonanceIf the amplitude of the sound is sufficiently large, resonant vibrations can shatter a wine glass.
This may be achieved by exceptionally powerful singers (and by average singers using electronic amplifiers).
http://www.youtube.com/watch?v=BE827gwnnk4
Tacoma Narrows Bridge
In 1940, the first Tacoma Narrows bridge was destroyed by resonance.
First Bridge
Second Bridge
Wind-forced oscillations that happened to match one of the bridge’s natural frequencies.
Tacoma Narrows Bridge
First Bridge
Second Bridge
http://www.youtube.com/watch?v=j-zczJXSxnw
Wave SpectrumTo appreciate what it takes to create a realistic
animation of water, such as the ocean, it’s useful to understand the concept of wave spectrum.
Real CGI
The Abyss (1989)
James Cameron’s The Abyss won an Oscar for Best Visual Effects, thanks to ILM’s creation of the first CGI character made of water.
The Old Man and the Sea (1999)
Aleksandr Petrov, the paint-on-glass animator, creates a realistic ocean with a full spectrum of waves, from major surges to minor ripples.
http://www.youtube.com/watch?v=l2_KszEnlq0
Spectral Decomposition
A complicated wave pattern may be decomposed as a sum of simple waves.
The graph of intensity (or power) versus frequency is the spectral decomposition.
TimeAm
plit
ud
e
Decomposition into waves
Frequency
Inte
nsi
ty
Class Demo: Wave Spectrum
Timbre and SpectrumA musical instrument playing a single note
produces not just that note’s frequency but others as well, mostly overtones.
The frequencies produced by a flute playing an A (slightly flat) show that the fundamental (436 Hz) and the harmonic (872 Hz) have almost the same amplitude.
The spectrum of a tuning fork has (mostly) a single peak at the fundamental.
Why Instruments Differ
The unique spectrum of frequencies for a musical instrument gives that instrument a unique signature, which is called the instrument’s timbre (or quality).
Playing this note (196 Hz)
Ocean Wave Spectrum
High FrequencyShort Wavelength
Low FrequencyLong Wavelength
Inte
nsi
ty High Winds
LowWinds
As the wind speed increases, the intensity of the large surge waves increases dramatically while the short ripples increases much less.
“Timber” of a MaterialSpectrum of waves will be different for different materials due to density, viscosity, surface tension, depth of the fluid, etc.
Gushing Oil Well
http://www.youtube.com/watch?v=pDyqhOL1ePU
Jello waves
Media That Transmit Sound
Sound travels better through elastic liquids and solids, such as water and rocks, than through air.
This is due to the close proximity of the atoms as they vibrate. Sonar used by whale and dolphins
Demo: Wave Spectrum
Strike the iron grate and listen to the sound.
Next, loop the string loop on your finger and let the iron grate hang freely.
Place your fingertips in your ears.
Strike the iron grate again and listen to the difference in the sound.
Hear richer, louder sound transmitted by string
Demo: What Your Voice Sounds Like
Your voice sounds different to you when you hear it from a recording.
This is because when you are speaking aloud, most sound waves reach your ear traveling through the solid flesh and bone of your skull.
Leave yourselfa voice-mail
Oil on the Water
Wave spectrum changes due to oil slick
Exxon Valdez accident
Shallow Water Waves
As waves enter shallow water, they slow down, grow taller and change shape.
From www.seafriends.org.nz
Approaching Shore
As waves enter shallow water, they slow, grow taller and change shape. At a depth of half its wave length, the rounded waves start to rise and their crests become shorter while their troughs lengthen. Although their period (frequency) stays the same, the waves slow down and their overall wave length shortens. From www.seafriends.org.nz
Wave Bending
When wave fronts approach a gently sloping beach on an angle, they slow down in the shallows, causing them to bend towards the beach. If the beach slopes gently enough, all breakers will eventually line up parallel to the beach.
Beach
Surf ZoneThe waves steepen and finally break in the surf when depth becomes less than 1.3 times their height.
Waves change shape in depths depending on their wave length, but break in shallows relating to their height!
From www.seafriends.org.nz
Breakers
Spilling breakers are arise from long waves breaking on gently sloping beaches. There are several rows of breakers.
Plunging breakers can occur on moderate sloping beaches. There is only one row of breakers.
Surging breakers surge over steeply sloping (but not vertical) beaches or rocks. Waves break one at a time.
From www.seafriends.org.nz
Clash of the Titans (1981)
Notice how fake the waves looks because the spectrum and the timing are wrong.
Tidal wave scenes were created with scale models.
http://www.youtube.com/watch?v=JgiOx1fQzoA
Clash of the Titans (2009)
With modern CGI and a good understanding of physics it’s possible to make believable waves.
Nevertheless, you can have good physics and still make a bad movie.