USING THE PHOTOS FROM THE AAPT PHYSICS PHOTO CONTEST

2. 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/photocontest.cfm

3. 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.

4. 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.

5. 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.

6. 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)

7. For example: photo by Erika Laman Please write a statement about the physics illustrated in this picture from the 2010 contest.

8. 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.

9. Please write a statement about the physics illustrated in the photo.Photo by Alex Mallison

10. 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

11. Please write a statement about the physics illustrated in the photo. Photo by Caitlin Morgan

12. 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.

13. Please write a statement about the physics illustrated in the photo. Photo by Rebecca Evans

14. 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.

15. Please describe the physics illustrated in the photo. Photo by Jason Connell

16. 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.

17. Please describe the physics illustrated in the photo. Photo by Joshua Lister

18. 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.

19. Please describe the physics illustrated in the photo. Photo by Anna Jones

20. 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.

21. Please describe the physics illustrated in the photo. Photo by Diana Greis

22. 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.

23. 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?theyear=2015 QUESTIONS? THANK YOU.