Transcript AAPT 1-16 Photo contest

USING THE PHOTOS FROM
THE AAPT PHYSICS PHOTO
CONTEST
Each year AAPT conducts a photo contest
for high school students.
http://aapt.org/Programs/contests/photoc
ontest.cfm
For about ten years, my students were
offered the opportunity to earn extra
credit for putting together an entry for the
contest. The assignment was required
extra credit; If they did a terrible job, they
got one point extra credit.
They could earn as much as 20 extra credit
points for turning in a submission that I
would send in for consideration for the
contest.
If they decided not to turn in an entry, I
would subtract 30 points from their grade.
Turning in an entry I’d submit for the
contest was worth as much as 50 points –
they would not loose 30 points and could
earn as much as 20 points. I RARELY had
students who did not turn in a photo and
description of the physics. Most did a good
job and had fun.
The website has Photo Contest winning
entries going back to 1998. This archive of
photos is a treasure trove of physics. They
might be used to introduce physics topics,
to illustrate that physics is everywhere,
and to stimulate discussion about physics
topics.
(All photos courtesy of the AAPT High
School Physics Photo Contest)
For example:
photo by
Erika Laman
Please write a statement about the physics
illustrated in this picture from the 2010 contest.
What the student wrote follows.
When light goes through water or any vacuum other than
air it bends. In water an object may seem larger and
closer than what the object appears to be at the surface.
This is called refraction: the bending of light when
passing from one transparent material to another.
The formula for refraction is described in Snell’s Law.
The equation for Snell's Law is n1sinθ1=n2sinθ2. N=1
while θ1 is the angle between the ray and the normal in
the first medium. θ2 is the angle between the ray and
normal in the second medium. When a light bends
through water the frequency stays the same while
the wavelength varies causing the change in the
direction of the ray, making the object appear closer and
larger underwater.
Please write a statement about the
physics illustrated in the photo.
Photo by Alex Mallison
The student wrote;
This photo was taken entirely by accident. The candy fell
into the sink and then sat there for a few seconds. The
running affect was instantly seen. After a quick shot the
photo was then looked at more in detail. The photo used
many points of physics to look so amazing. Laminar flow
does an excellent job of making the red color wrap
around and go down the drain in a fine point. The drain
was slowly letting water leak in thus pulling the water
around the candy. Laminar flow states that when a
steady flow of water is put around an object it will
spread out to surpass it. The water will then go back into
the fine point it previously was in. Density also played a
big part in this photo. The density of the dissolved candy
solution is much heavier than water. If the density of the
dissolved candy solution was the same as water the red
lines seen in the bottom of the sink would not have been
seen. However, the density was not so heavy that the
particles could not have been moved. This idea could be
repeated with any type of candy
Please write a statement about the physics
illustrated in the photo. Photo by Caitlin Morgan
The student wrote;
It is obvious that there are only three different
colors of light, but in the middle of the three
beams, there is a big white spot. Why? Blue,
red, and green are the additive primary colors.
Below the white spot in the picture, blue and red
mix to create magenta. To the right of the white
spot, red and green mix to create yellow. And to
the left of the white spot, blue and green mix to
create cyan. When looking at the mixture of
these three colors from a distance, the mixtures
of the spots provide a complete range of colors,
including white. Therefore, when the three
beams of light intersect in the picture, the white
spot becomes apparent.
Please write a statement about the physics
illustrated in the photo. Photo by Rebecca Evans
The student wrote;
From the time the diver jumps from the board, up until
the moment of suspension (shown in picture), the diver
is building up potential energy. Upon descending, the
diver’s kinetic energy increases and the potential energy
decreases. The diver’s kinetic energy, right before she
hits the water, should be the same amount as the
potential energy at the moment of suspension. This is
the law of conservation of energy.
Newton’s third law is also demonstrated in this photo. As
the diver exerts a force on the diving board, the diving
board exerts a force on the diver, giving her enough
energy to suspend in air and execute the dive.
Please describe the physics illustrated in the
photo. Photo by Jason Connell
The student wrote;
When I set out to take this picture I was looking to
illustrate trajectory and how both liquids would hit the
ground at the same time. However during my hundreds
of attempts to capture this phenomenon I accidentally
stumbled upon this picture and thought it was too
beautiful to pass up. So my new topic is vector motion.
This picture shows two vectors. The red stream is a
vertical vector and the blue stream is a horizontal vector.
When they make contact, the resulting purple stream is
moving in a direction that is a combination of the two
vectors which roughly bisects the 90 degree angle
created by the two previously existing streams. This
suggests that the force of the two streams are similar.
Please describe the physics illustrated in the
photo.
Photo by Joshua Lister
Here is what the student wrote;
In this photo there is a stack of magnets
sticking out perpendicular from a chalk
board. Eight screws are attached to
strings and the screws are suspended in
the air by the force of the magnets. From
a vertical view of the system the strings
make a good representation of a force
vector diagram. The equal and opposite
force of the strings and the force of the
magnet allow the screws to be suspended
in the air.
Please describe the physics illustrated in the
photo. Photo by Anna Jones
The student wrote;
This photograph demonstrates projectile
motion in two dimensions, the X and the Y
dimensions. The horse is at the highest
point of his path across the jump;
therefore, the velocity in the Y direction at
this point is zero. The acceleration in the X
direction remains zero throughout the
path because no external forces are
causing the horse to accelerate in the X
direction. The horse's path follows a
parabolic path across the jump.
Please describe the physics illustrated in the
photo.
Photo by Diana Greis
The student wrote;
This contrived photo shows a gymnast performing what is called a
giant in gymnastics. An object in circular motion moves at a
constant speed with a fixed radius. Because the gymnast’s height is
constant, the radius of the circle she makes from her toes to her
hands on the bar is also constant. As the gymnast approaches the
downward position, the potential energy decreases, and she picks
up speed through kinetic energy. As she starts moving back up in
the rotation, kinetic energy will decrease, and a force is needed to
continue the rotation. The gymnast’s body is mapped out like a
motion diagram; the camera captures more pictures at the top of
the giant because she is slowing down and vice versa picking up
speed at the bottom. Arching her body and bending her knees just
slightly moves the center of mass closer to the bar. This provides
the kinetic energy to get her around the bar. Her straight body
position will also help reduce the effects of gravity. The centripetal
force towards the inside of the circle is what is keeping her holding
on to the bar. To continue going around and around as long as her
hands can stand it, she would continue this stretching outward as
she goes over the top and bottom and tries to move her legs up
past her shoulder angle to keep the center of mass close to the
center of rotation. Once she stops adding force, she will stop.
In addition to the archived winning
entries, the top 100 photos from the
contest from the current year are also
archived. These do not include the
dialog written by the students.
http://aapt.org/Programs/contests/gallery.cfm?the
year=2015
QUESTIONS?
THANK YOU.