Task 5
Title: Airzooka Smoke Rings
ELA Component: Interview
Reason: I chose this option for my project because it would better suit me to get advice from an experienced person. I would interview a person that has already dealt with this project for an insight on exactly what to do. this could better help me and those in the future who are interested in this project.
INTERVIEW
-Me: First off, are smoke rings generators easy to make?
-Mr. Ekinci: Smoke ring generators are easy to make from free materials that can be found in any home.
-Me: What is the logic behind this project?
-Mr. Ekinci: Aerodynamic drag from the edge of the ring that makes the front of the gun and the still air outside of the gun causes the exhausted air to begin rotating as the red arrow at the top of the drawing shows. This creates the toroidal vortex. Because it's rotating, the velocity inside the vortex is greater than the velocity of the air outside it. Bernoulli's law states that the faster a flow of air is moving the lower its pressure. Since the air inside the torus is moving and the air outside isn't, that means that the pressure inside the torus is lower than the outside.
-Me: What is the smoke given off by the guns?
-Mr. Ekinci: It isn't really smoke; it's a fog: a cloud of microscopic droplets so small that they float in the air.
-Me: How far can the vortex travel before the disintegrate?
-Mr. Ekinci: With a little practice, it was quite easy to shoot a cup off of someone's head from 20 feet away.
-Me: How about dry-ice fog?
-Mr. Ekinci: The fog produced by dry ice consists of water vapor condensed out of the air by the low temperature of the dry ice. The same thing can be seen with regular ice, though its higher temperature is only able to create the lightest wisps of fog close to its surface. The fog created by dry ice stays around longer than that from a teapot because it's cool and therefore evaporates much slower.
-Me: And finally, what about square smoke rings?
-Mr. Ekinci: At first this sounds impossible because most of our experience with naturally occurring round things, like bubbles, can only exist in the round form. But, that's because their structure is dominated by surface tension forces. Smoke rings don't have this limitation. I believe what happens is that the vortex wants to be circular so it pulls the corners of the square in. But, once the corners get moving they have inertia and keep moving past the position of the ideal ring shape and carry over inward, creating a diamond shape. The vortex doesn't like this either so it draws the ring sections that are inside the desired ring diameter outward. Again, they overshoot and the ring bounces back to a square shape. This oscillation is difficult to see unless the ring has a very clean, shape shape.
-Me: What keeps the smoke ring moving and why does it eventually stop?
-Mr. Ekinci: The energy that is used to move it forward and keeps the vortex rotating is taken from the inertia of the rotating air in the vortex. Inertia is the tendency of anything in motion to keep moving. Even though we can't see it, feel it, or taste it, air has weight and therefore once it's in motion it has inertia that'll tend to keep it in motion. The spinning of the air in the torus is where the energy that keeps the torus moving is stored. Eventually, air friction eats away all the energy stored in the vortex and the smoke ring drifts to a stop.
PBL Task 7
I have chosen to focus on the Airzooka Smoke Rings for my Science PBL Project. For my ELA connection, i will conduct an interview (option 5). I will present this interview by adding it as a document under my PBL website.