Mysteries of the Cincinnati Fire Kite

Most kites take a great deal of work to get up in the air. These kites fly up on their own. How? Because they're being lit on fire. And all you need to make them is tape, newspaper, and matches.


The name of this particular experiment puzzles me. The fact that it flies and its shape - at least in the beginning - are vaguely kite-like. The fire is also pretty obvious. But I haven't been able to find out what this particular little demonstration has to do with Cincinnati. If any Cincinnatan is reading this, and knows how their fair city got mixed up with an unstable, flying ball of fire, do please let me know.

The fire kite is easy to make. Grab a sheet of newspaper, one that's a wide, two-page spread. Grab one set of diagonal corners and pull them towards each other. Attach them together with tape, but let them pooch out from the main page. Don't fold them down flat. Now grab the other diagonal set of corners and do the same.

What you'll have, when you're done, should look like a pregnant kite. Grab this, and some matches or a lighter, and take it out to a large empty parking lot, or an empty basketball court. Lie it down on its taped-up belly, with the flat side facing up. As quickly as possible, light all for corners of the kite. It will begin to burn for a while, its corners collapsing inward. Sometimes the effect will happen right away. Most of the time, just when it looks burned down to ash, it will lift off the ground and shoot, flaming, into the air. This is very cool, especially at night when you can see the last bits of flaming paper dissolve. It's also the reason why you can only do this on a large stretch of nonflammable ground. If the kite gets a bit of a crosswind, it can blow onto leaves or bushes.

As the paper burns, it gets lighter. It also tends to curl into a ball, which makes the sides curl inwards and the holes at the bottom open up. This leaves a ball of paper curled around a lot of hot air. As we've seen with ballooning, hot air rises. It seems like the kite would always lift off the ground immediately, but even beyond the relative heaviness of the unburned paper, there's sometimes physics keeping it down. Air only rises when it's hotter than the air around it. While the main fire is burning, it can heat the air all around the kite. When the fire dies down, and the cool air rushes back in, the hot air inside the kite is suddenly less dense than the air around it, and rises up.

Via Instructables.


Quasi Hatrack

We did something similar when we were kids.

The (politically incorrect) Polish rocket: Take a full size paper towel and fold it in four quarters the long way. Tuck it so that the outside sections overlap and make a triangular prism which you can stand up on end. Light the top of the prism and when the fire gets to the bottom the ashes lift up into the air.