Giant Air Cannon - Feedback from our Visitors

Q: Why not just use dry ice [instead of ammonia and hydrochloric acid]? Not quite as dangerous to the operator.

A: True, but not self-replenishing. If you placed only dry ice in the air cannon, then to get a really good smoke ring, you'd have to wait awhile, because the CO2 wouldn't sublimate very quickly. One thing that I have tried is having a separate dry ice smoke generator, which was just a tub of dry ice and hot water. I then had to dip out fog using a large bowl, and pour it into the air cannon. You could rig up a continuous supply using dryer hose connected to either a dry ice smoke generator, or a commercial fog machine.
See my Fog Generator page.

Q: Hi
I'm a sixth grader and my mom and I found your web page when I was looking up vortex's because I'm doing a science project on a vortex cannon. I am making mine out of a box. I have a few questions to ask you. In one of your papers it talks about how are vortexes used in the real world. It says there are machines such as

A vortex vent,
vortex mill,
vortex thruster, and
liquid piston engine

plus a toy gun called a WHAM-O. Are there any other kinds stuff used in the world?
What kind of work do you do and is it related to vortex cannon?
How long did it take you in school and in the workplace to become familiar with the idea of vortex cannons? What kind of school did you have to go to work in this area?
Have there been many other kids that have asked you questions about vortex cannons?
Do you think that there is a big future for vortex cannons in the world? If so, what areas? Is there a lot of work being done in the space program with vortex cannons?
I have to complete my research in this area by the end of this week. I would like you to please write back, if you would.
THANK YOU

A: I think you are confusing my page with Bill Beaty's Vortex Ring Launcher page.

Q: WHERE CAN I GET ACID FROM THE ONE YOU ARE TALKING ABOUT

A: Muriatic acid is sold at swimming pool supply stores and at some janitorial supply outlets.

the thing is GGGGrrrrrrreat!!!!!!!

Q: For the house hold ammonia chemical formula, you put NH₃OH. That doesn't make sense because hydrogen wouldn't be listed twice. It would be NH₄O.
Thanks.

A: It is usually listed as NH₃OH to give an indication of its structure. The structure is a nitrogen atom surrounded by hydrogens, and also a hydroxyl group, OH^-.

Q: Loved your site, you gave excellent information. I found yor site from Bill Beaty's Vortex Ring Launcher page.
I will use his garbage can launcher, with your smoke formula for my 8th grade science fair that is coming up.
Thanks,
Blaine Hilton

A: That's great, Blaine!

Q: I don't surpose you could tell me where I can get some software to produce different wavelengths of sound for the experiment?
Thanks,
Blaine Hilton

A: Try any of these:

Thank you very much! I have found some great software with your links. I will make a website with my data and I'll be sure to let you know about it.
Thanks again,
Blaine Hilton

Q: This is information which a student will be using for his science fair project. He intends to builds an air cannon. He intends to place the cannon at different angles to see how far the object will travel. Can you suggest what he might use for research of the literature.
I am a librarian, not the science teacher so I know little of scientific terms we should use to find information. Am I dealing with trajectory, or force? What is the scientific principle behind this?
We thank you for any information. The student is quite excited by your Web Page.
Sincerely,
Carolyn

A: Hi Carolyn,
I'm afraid he will fail if he fires vortex rings. They don't behave ballistically. If he fires objects from the cannon, then he can explore the relationship between angle and range.
I suggest he look in a good basic physics book like that by Halliday and Resnick.
"Ballistic trajectory" might be a good search term. He might want to predict the angle at which he gets maximum range. He would have to make sure that the firing mechanism is pulled back the same distance each time. He would also want to make lots of firings and average the range measurements for each angle setting.
By the way, the "theoretical answer" will be 45 degrees.

Q: I have a question. I am twelve years old and we are having a science fair soon do you think it is safe to have the air cannon there??
If not write back to me if you think it would be harmless to have it there. Write back and tell me where I can get the hydrochloric acid and the household ammonia. I would still like where to get the stuff even if it's not safe to try at the science fair because I would like to make one myself maybe at home.
Sincerely,
Timon

A: Timon, It should be safe if done carefully in a well controlled environment. But to be safer, you may want to use dry ice. To do that, get some dry ice and make a smoke generator. This can be a styrofoam ice chest with some four inch dryer hose attached to the cover. Attach the other end of the hose to a hole you make in the side of your air cannon. See Fog Generator.
Keep the dry ice in the container. Pour in a small amount of HOT water, and replace the lid. Clouds of water vapor will be pumped into the air cannon. This "smoke" is completely safe, even when fired directly into someone's face. (It's lots more fun that way!)
If you still want to use acid and ammonia, purchase "muriatic acid" at a swimming pool supply, or janitorial supply store. Some grocery stores even stock this stuff (at least, some do in the summertime).
Dry ice, by the way, is available where bulk ice is sold. It is usually listed in the Yellow Pages under "Dry Ice".

Thank you sooooooooooo much for putting that air cannon experiment on your site. I did it for school and i got an A+ and won 1st place in the fair!
Thanks Again,
Rafael

Q: Hi,
I am doing a project on the giant air cannon for our science fair, and I was wondering if I could get nore data so I can make graphs to help me in my project! I am not sure on what my hypothesis would be either, so if you could help with that too, I would be very thankful! Sincerly,
Student

A: You should build the air cannon, and take data yourself! That's what a science project is!
A science experiment reveals the relationship between variables. You change a variable and measure whether or not, the other one changes. If it does, a graph can help you determine how.
For the air cannon, what are some of the variables in its operation? Are there any? Are they measurable?
If not, then the giant air cannon might not be appropriate for a science fair, even though it is fun!
I wish you luck!