At every section meeting one of our most popular portions is the Share n Tell during which participants have five minutes to share a demo, idea, concept, book, problem, example, etc. Talkative participants must fear the dreaded gong at the end of five minutes. Below please find notes and relevant links from the special double session of Share n Tell from our Fall NCNAAPT Section Meeting and mini-conference:
Don Payne, Carondelet High School
A Piezo Electric popper (spark fed) has been adapted to drive a small toy car. A film canister is filled with either ethanol or Bonaca breath spray. By igniting the propellent the can be shot in one direction as the car moves in the other. Can be used for momentum collisions or projectile motion and potentially adapted for use with photogates. Black film cans with gray lids with a lid work the best and a Nerf ball was added tot the launching end of the can for safety for projectiles. Nicknamed as the “Bonaca Cannon” at the conference, the car is made from a small wood base, Pisco (?) aluminum axle wheels and electric leads for ignition.
- Piezo Electric Car
Paul Robinson, San Mateo High School
Horace (Rog) Lucidio taught in Pittsburgh and then Fresno. He has since retired and published a book called “Educational Genocide” just recently out. It is available from Amazon or AbeBooks, and comes highly recommended. Read the press release here.
Bernard C, retired
Bernard demonstrated a “Poisson’s Spot” demonstration, misnamed because you shouldn’t get light behind a barrier which in this case is a 4” “ball bearing” used to block the microwave signal AC Amplifier (with sound signal so it doesn’t need to be in the dark). Can be shown to block specific zones so that it acts as a positive lens and increase the size of the signal using Fresnel Zoning.
Bree Barnett Dreyfuss, Amador Valley High School
Bree shared a “Center of Mass” Project that students do while studying Torque and Center of Mass. The project is adjusted for a variety of levels including freshmen in Conceptual Physics. There is a website with details and YouTube video that explains the details of the project to students. Sophomores to Seniors in regular Physics have to bring in a balanced object, either a mobile, 3D sculpture or flat oddly shaped object. The flat character/ geographic region is the most popular and allows for the most creativity. Students have also used powerpoint, made videos with classmates and even hand drawn animations in order to demonstrate their understanding of Center of Mass. For younger freshmen, the project is restricted to create a flat creative object and bring it in to class. Then together, they learn how to find the center of mass of their object using a plumb bob.
Cailin Creighton, iFly educational leader
Cailin is in charge of the education program at the Union City iFly facility and has offered affordable field trips for teachers. She shared models and instructions of a handmade vertical wind tunnel out of a cereal box and plastic bottle. Instructions to come soon. Cailin used a Kellog’s 18 oz cereal box and an Archer Farms water bottle – plastic not glass to create the frame of the wind tunnel. A 80 mm commuter fan hooked up to a 9V battery runs the fan and allows a light object like tissue paper to fly. This model models the Hollywood (single side tunnel) while the local Union City one has two sides of fans feeding in to the tunnel. Turning vanes are not necessary for the cereal box model due to the simplicity of the design. It was suggested to try adding dry ice to simulate a tornado. 1” Styrofoam balls cut in half will fly, while a whole ball will not fly which is interesting because they have the same surface area but a different weight. Cailin’s contact information is Cailin@iflysfbay.com.
Paul Doherty, Exploratorium
Paul shared the classic Reaction Time experiment adapted to work for a baseball bat that is marked with reaction times. Average human reaction is 0.16 s, volunteer Pablo got 0.22s, then 0.2 s which is consistent with experiments as students improve with time.
Putting a stiff card at the top of the baseball bat acts as an amplifier. You can strike the bat at different locations and hear an amplified thud. The sound will decrease as you reach the “sweet spot” which is a vibrational node. This is why hitting a home run on the sweet spot feels better than hitting off the spot.
Don Rathjen, Exploratorium
A Fan cart is helpful in teaching Newton’s Third Law by moving the fan and sail positions to show that when both are on the same cart it will not move. Don has a fabulous design that is very low friction. Don also added a waterbottle that was cut in half with the “sport top” that pops up that can be used to create a consistent drip timer. This can be added to the fan cart to work as a drip timer for motion to model motion.
Lee Trampleasure, Carondelet High School
Lee (who had lost his voice) shared a humorous PowerPoint on Newtons three laws (Newton, North Carolina, that is) with single picture explanations of each of Newton’s Three Laws:
- 1st law: 35 mph Speed Limit sign
- 2nd Law: “no left turn” sign
- 3rd Law: “no parking” sign
Pauline Seales
Pauline described a demo in which she asks a “strong” student to bend a nail with their bare hands, which they can’t do. She then asks a “small” student to bend it and hands them two pieces of metal pipe that are inserted on each end of the nail (increasing the lever arm distance) and they are able to bend it easily.
Pauline also modeled using a pre-cut mop handle attached with a PVC pipe to show how balanced Torques does not mean balanced forces. Students often don’t believe her and have to weigh the broom head (heavier) and handle (lighter) themselves because they don’t believe her.
Dean Baird, Rio Americano High School
Showed Simple Harmonica Motion:
Dean also discussed a large mural of white light reflected on an equilateral triangle outside his room with almost the right angles. He showed a video of a Newton’s Cradle that does not behave normally as discussed in his blogpost.
Paul Doherty added that the Exploratorium recently created a large Newton’s “ridable” Cradle with 1 meter diameter Lexican balls. Paul also told us about the Exploratorium’s After Dark adult only program that goes from 6-9pm, on the first Thursday of every month.
Rob Benn, American High School
Using video in the classroom using iMovie, iPods, iTouches, etc. in order to model Bridges, motion at Great America, etc. Can also be used with high speed cameras. VideoPoint is additional software that you can use. The FH100 Casio will do 1000 frames/ second but is $300. Students participate in Knieval Physics which makes for interesting videos. Due to the wealth of information available from Rob, he was encourage to do a workshop next time.
Dean Baird, Rio Americano High School
Dean showed an additional short film of a Newton’s Cradle in which the balls appear to fly apart. After showing a hint video we were able to see the answer, all videos available on his blogpost.
J Robert Dobbson
Dobbson shared a Gaussian Cannon that can be made rather than bought with ½” steel ball bearings and neodymium magnets on a plastic ruler. Having an assistant pull the last ball, last two balls and last three balls off the end you can learn that the approximate magnetic strength changes with proximity to the neodymium magnet. Allowing the first ball to fall down a small incline the loss of potential energy becomes kinetic energy. The ball also gains energy as it is attracted to the magnet and as the energy grows the last ball flies off at a larger velocity.
Dobbson also shared a coil of magnetic wired that he had to modify so that it appropriately showed the magnetic field inside the coil without being affected by the lights. He coiled 10 cm, made a Uturn in the coil for 20 cm, used another Uturn and then another 10 cm.
Rodger Moorehouse, Pomona
Rodger discussed the history of different temperature scales and their origins.
Bree Barnett Dreyfuss, Amador Valley High School
Bree shared a variation of the Blinky Light activity from her website as well as an online game about Torque called Levers.
Paul Robinson, San Mateo High School
Paul shared the ramp he designed which is very repeatable and consistent. He was unable to show his baseball videos but they are available on his website.
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