Transcript L23_EandM

Upcoming
Deadlines
Have clicker ready
Second Term Paper
Science Fact or Cinematic Fiction?
Due Tuesday, November 13th (Next week)
100 points (50 points if late)
Homework #11 – Building a Scene in Maya
Due Tuesday, November 20th (In two weeks)
20 points (10 points if late)
For full schedule, visit course website:
www.Animation123.com
SPECIAL OPTION
If you scored 80 points or higher on your
first term paper then you have the option
of skipping the second term paper.
If you wish to exercise this option then create a blog entry
entitled “Second Term Paper” and in that entry write:
No term paper is being submitted.
Submit the URL for this blog posting for the assignment;
I will then enter your points using Canvas.
Autodesk Maya
For homeworks #11
and #12 you will be
using Maya, a 3D
graphics program.
You can download a
free 30-day trial
version of Maya from
the Autodesk website.
Homework #11
For this assignment you will create a scene using Maya, a
popular software application used in animation.
The scene consists of a floor, a single wall in the
background, and some objects in the foreground.
Those objects need to be arranged so that they create the
shape of the initials of your name.
Position the two letters so that they rest on the floor or on
each other; do not have them touching the vertical wall.
Homework #11
This scene was created by Tom McKee.
Homework #11
Post your rendered image in a blog entry
entitled “Building a Scene in Maya.”
Due by 8am on Tuesday, November 20th
20 points (if late, 10 points)
Extra Credit (10 points):
Create images of your scene lit using
one-point, two-point, and three-point lighting.
Homework #11
Two-point
Lighting
One-point
Lighting
Three-point
Lighting
Animation Show of Shows
TONIGHT!
University
Theater
@ 7pm
Free
admission!
Survey Question
In how many other classes, either in
college or high school, have you
used a clicker system?
A) None
B) One
C) Two or Three
D) Four to Six
E) More than six
Review Question
Sparks from sparkler
don’t burn skin because:
A) The sparks are bright
but don’t have a high
temperature.
B) The sparks are high
temperature but they
don’t have much
internal energy.
C) The sparks have a
very low conductivity.
.
.
.
.
.
By analogy, grains of sand that fall
from a great height doesn’t have as
much energy as a cannonball that
falls a couple of feet.
.
The sparkler sparks have high
temperature (5000 ºF) and high
conductivity (burning iron) but are
very small, with little mass.
.
B) The sparks are high
temperature but they
don’t have much
internal energy.
.
Review Question
x x
Review Question
Which of these is not a mechanism
for heat transfer?
A) Conduction
B) Radiation
C) Reduction
D) Convection
Heat Transfer
C) Reduction
Radiation
Convection
Conduction
Effects Animation:
Electricity &
Magnetism
The Force
Electrical and magnetic phenomena are the
inspiration for many special effects, such as the
mysterious “Force” in the Star Wars epics.
Electric Charges and Forces
There are two types of charge:
positive charges and negative charges
REPEL
REPEL
ATTRACT
Like charges repel, opposite charges attract.
Charging by Friction/Contact
Electrons move easily
so an object can
become charged by
rubbing electrons off
the object’s surface.
• Brush your hair with a plastic
comb.
• Walk across a carpet with
plastic-soled shoes.
Electrons
taken off of
fur onto
rubber rod
Demo: Electroscope
The “legs” of an
electroscope
separate when
the electroscope
is charged due to
the repulsion of
like charge on the
two legs.
Charged ebonite
rod deposits
negative charge
(electrons) onto
electroscope.
“Legs”
Demo: Dial Electroscope
Alternative design for electroscope
Neutral
Charged
Demo: Van de Graff Generator
Van de Graff deposits
large quantities of
excess charge on its
globe.
A person with long hair
can become a human
electroscope.
Repulsion also demonstrated with
pie plates, Rice Krispies, etc.
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Demo: Static Cling
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Static electric charges
can cause objects to
be attracted.
This happens when
the charged object
induces opposite
charges closer.
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Wall
Reminder:
Start cooking
hotdog
Plastic Insulators
Plastic insulation on step of van de
Graff and charge wand keep charge
from leaving the metal balls.
Plastic insulation on wire prevents
charge to leave wire except at the
ends, where the conducting metal is
exposed.
Demo: Resistance of Water
Pure water has very high resistance;
impurities, such as salt, lower resistance.
When salt dissolves
the sodium and
chlorine atoms are
charged (ions).
These mobile
charges carry the
current in the water.
CURRENT
Light Bulb
Ammeter
Salty
Water
Power
Supply
Demo: Tesla Coil
Air is an insulator but at high voltages it can
conduct electricity as lightning.
Portable
Tesla coil
Tesla Coils
Very high voltages achieved with
large Tesla coils.
Homemade, backyard model
Fry’s Superstore, Fremont CA
Jacob’s Ladder
Ohmic heating of the air creates an
electrical discharge visible.
Spark begins near
the bottom, where
the gap is small.
The current heats the
air in the gap,
causing it to rise
since hot air is
buoyant.
Check out
the 5 foot
Jacob’s
Ladder
outside our
classroom
Jacob’s Ladder
Ohmic Heating
Flowing electrons
strike atoms in a
conductor, heating
the material.
Hellboy (2004)
Toaster
http://www.youtube.com/watch?v=OGezvYafezE
Demo: Ohmic Cooking
An electric current running through a hot dog
generates enough heat to cook it.
Strange light show
when using a pickle
in place of hot dog.
Similar to sodium
lamp discharge.
Nervous System
Nervous systems in animals use
electrical currents to signal the
contraction and relaxation of
muscles.
Frog leg jumps when
electrical current
passes through it.
Presto (2008)
Common visual gag is the
uncontrollable twitching of
a person’s muscles.
Notice
Jacob’s
Ladder
in Presto’s
hair
http://www.youtube.com/watch?v=mw-fs19kTGM
Quiz Question
Electrocution (death
by electric shock) is
usually due to:
A) Ohmic heating of
the internal organs
of the body.
B) Disruption of the
body’s electrical
nervous system.
Conduction in Human Heart
B) Disruption of the body’s
electrical nervous system.
The most important electrical
signal in our body is the
periodic signal that contracts
and relaxes our heart
muscle to pump blood.
Without a constant flow of
blood the brain can suffer
permanent damage.
SA
AV
Electric Shock
The damaging effects of shock are the result of
current passing through the body.
Current depends on
the voltage and on
electrical resistance.
When dry, skin’s
resistance around
100,000 .
Resistance drops as
low as 100  when
wet and salty.
Effects of Electric Shock on Human Body
Current (A)
Effect
0.001
Can be felt
0.005
Is painful
0.010
Causes involuntary muscle
contractions (spasms)
0.015
Causes loss of muscle control
0.070
If through the heart, serious
disruption; probably fatal if
current lasts for more than 1 s
Frankenstein (1931)
Electricity brings
Frankenstein’s
monster to life in the
1931 horror classic
yet it’s not mentioned
in the original book,
written in 1818 by
Mary Shelley.
Bolts for
electrical
contact
http://www.youtube.com/watch?v=8H3dFh6GA-A
Magnetism
Magnetism produces
an invisible force
that’s also popular in
science fiction.
Magnetic Forces
Observations regarding magnets:
Iron (and a few other metals) are
ferromagnetic, which means they
can become magnetized.
Magnets attract ferromagnetic
metals.
Two magnets can either attract or
repel each other depending on
poles.
Iron Ore
Demo: Magnetism & Money
Most US coins are not made of ferromagnetic materials but
many other countries use iron steel in their currency.
Some pennies
were made of
steel during
World War II
Iron is in the ink used in US paper
currency to avoid counterfeiting.
Some Euro
coins contain
steel
Buffalo nickels
are 25% nickel
metal, which is
ferromagnetic
Magnetizing Iron
Magnetic domains can be induced to align
by an external magnetic field.
S
N S
Strong
Magnet
Strong
Magnet
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Demo: Magnetizing Iron
Magnetic domains in iron nails are
induced to align by proximity of
the strong magnet
Each nail becomes itself a magnet,
which in turn magnetizes the nail
below it, forming a chain.
When the strong magnet is
removed, most of the domains
un-align and nail lose most of
their magnetization.
Quiz Question
Wile E. Coyote is surprised when a big metal can
of TNT comes flying in, pulled in by his magnet.
In reality, the force of the can
on the magnet is just as
strong as the pull of the
magnet is on the can of TNT.
A) True
B) False
Magnets & Wile E. Coyote
From “Zipping Along”
A) True.
Another example of
action/reaction principle
(Newton’s Third Law).
Action force is magnet
pulling TNT can.
Reaction force is TNT can
pulling magnet.
Demo: Electromagnets
Electromagnet
created by passing
current through a
coil of wire.
Electromagnet is
stronger when an
iron bar is inserted
within the coil.
N
Wire
Coil
S
Connect to
battery or
power supply
Iron Bar
Demo: Electromagnetic Oscillations
Put alternating current into an
electromagnet and you create an
oscillating magnetic field.
This oscillating magnetic field
induces electrical currents by
inducing electrical field oscillations.
This is, effectively, a very low
frequency electromagnetic antenna.
Put a copper ring in the magnetic
field and it gets hot from the
induced current (Ohmic heating)
Coil with bulb
Oscillating
Magnetic
Field
ElectroMagnet
Connect to
alternating
current (AC)
EMP (ElectroMagnetic Pulse)
A strong, rapidly fluctuating magnetic pulse can
induce high voltage, causing strong currents.
In 1962, a nuclear test in
the Pacific produced an
EMP that knocked out
300 streetlights and
telephone service in the
Hawaiian islands, 900
miles from the explosion.
Starfish Prime, as seen from Honolulu
Call of Duty:
Modern Warfare 2 (2009)
In the “Second Sun” campaign mission a
nuclear missile creates a high-altitude EMP.
Streetlights explode, helicopters fall out of the sky, and
electronic equipment on weapons is “fried.”
Demo: Magnetic Brakes
Strong magnet dropped into
a copper pipe falls slowly
due to secondary magnetic
field induced by its motion.
Great America’s Drop
Zone has a 22 story
freefall, lasting four
seconds, decelerated by
magnetic braking.
Next Lecture
Lighting & Optics
Part I
Next Tuesday’s Assignment:
Second Term Paper