Most of us have been captivated by smoke rings at some point, whether at a science fair or as a party trick. But how do they actually form? Some have learned and are able to produce smoke rings with their mouths, but we decided to take it a step further and build our own smoke ring vortex cannon. Credit to my partners in this how-to project – Peter, Pyper, Mark, and Alec! Check out the video below:
How Are Smoke Rings Formed
Though the science behind vortex/air/smoke rings is complex and involves aerodynamics, the concept is very simple. As air is pushed through a hole because of a pressure change, the edges of the hole cause resistance and drag on the air passing through (fig.1).
As the air exits the hole, the resistance causes a swirling motion on the outer edges of the moving air, in a doughnut shape. Once the air leaves the hole, the motion continues as the ring moves through the air (fig.2).
The ring of air will continue to move in the initial direction until the atmosphere resistance interrupts the ring’s motion.
How to Make a Vortex Ring
Creating a vortex ring is really simple. A vortex ring machine can be made by cutting a round hole in the bottom of a tupperwear container and covering the other end with cling-wrap or a balloon. Tapping on the wrap/balloon will cause air to exit the container from the round hole, creating vortex rings. Our first prototype consisted of this setup, and once smoke was added, produced small vortex rings.
This wasn’t impressive enough, so we upped the size a little, by ~8x.
- Some sheet aluminium. We purchased ours from the local hardware store for about $20 CND. It came in a roll of about 18″ by 10′.
- Plywood. Ideally a few pieces of 4×8 half inch thick. They’re about $8 a sheet from the hardware store, but you might be able to snag some from a local jobsite if you ask nicely!
- Some pool/pond liner. This was the hardest to get, as its expensive and we don’t need an entire roll for the project. I was lucky and had this role from our backyard pond project (fig.3)
- A 2×2 about 8′ long. This is really just a support system for the two ends of the drum.
- A smoke machine! Easy to get, generally from Wal-Mart or similar general store.
Putting it all Together
This part is entirely up to you. The basic design consists of two rings of plywood, five supports, a front hole plate (which allows for changing hole size), an aluminium shell, and a rubber drum cover. Take a look at the following pictures to help your personally design:
You’ve got yourself a super cool toy to impress people with! Of course, its giant and awkward to store so it’ll probably end up being a table. Or maybe a giant base drum for those crazy jam sessions? Set up some cans or cups in a pyramid and try to knock them over from ridiculous distances. Or frighten innocent passer-bys with blasts of air!
If this tickled your creative senses, check out Arduino Bluetooth Communication!
Check out this awesome video involving GIANT smoke rings in the emission of CO2 gas: