seem like they could be really cool under some circumstances (the ones that appeal to my inner 14-year-old). But are the properties that make a fluid inflammable at odds with the properties that allow it to form a bubble?
Seen on Mythbusters: bubble methane through soapy( dishwashing) water.
But none of these involve the material that makes up the bubbles being particularly flammable. The bubbles are filled with a flammable gas and are both strong enough to hold the the gas in place, but fragile enough to not get in the way of it burning.
If you want the bubble itself to be flammable, that’s probably more work.
The Wikipedia article on foam has examples of foam aluminum and plastic. Soap bubbles won’t burn, but most foam plastics were created by bubbling gas through liquid plastic, and most plastics will burn.
Diesel fuel will foam a little when shaken, and it is certainly flammable. I wish that I could think of other substances that are liquid at room temperature and will foam.
My father (a high school science teacher) used to inject oxygen and hydrogen in a 1:2 ratio under a film of soap on someone palm - this would create a bubble of gas which when lit, would explode with a sound like a rifle shot. Since it was exploding on the palm of your hand, most of the energy was directed upwards, and it just felt like someone slapping your palm.
Grim
This video shows a set-up for making hydrogen/oxygen bubbles. Unfortunately, it appears the website is now down (presumably due to the publication of the book version).
Here’s how to make inflammable balloons. You’ll need some calcium carbide, which is used in old-fashioned miner’s lamps. Cavers use 'em too, or they did when I was a kid.
Do this outdoors, away from things that might catch fire.
Stuff some calcium carbide rock inside a toy balloon, then stretch its neck around your outdoor hose or faucet. Put a little water in, to about the size of your fist, then tie off the balloon. The rocks and water will evolve acetylene, the welder’s gas, and the balloon will grow with the gas. When the balloon gets as big as it can get without bursting, it’s time to light it.
I used a kitchen match, rubber-banded to a prong of a leaf rake, with me at the other end of the handle, to set it off. When the match’s flame reaches the balloon, it will burst, and the acetylene makes a nice ball of fire. I don’t recommend getting any closer to the fireball than that.
Small fiery stunts!
My short stint as a frat pledge required me to always carry a Zippo lighter. We learned to flip open the lid and light the flame in one quick motion. Most of us learned other silly tricks. A Zippo in a pocket can be opened far enough to strike the spark wheel and get a brief flame. Clicking the lid shut puts it out. In the daytime, nobody knows but you. In the dark, people can see your flash in the pants.
Loosely make a fist, and use a butane lighter to fill the tube of your hand with gas. Strike the spark wheel while opening your hand, and you have a quick wisp of flame in your palm. With a little practice, the lighter is not so apparent.
Squirt a little lighter fluid in an empty drink can. After a few seconds, the can is filled with vapor. Put a lit match to the open hole, and you’ll get a quick jet of flame that makes a “fweet.” Instantly, it uses up all the oxygen and goes out, and it usually puts out your match, too. Every few seconds, it’s ready to do it again.
Yep, I remember in college freshman chemistry the professor did a lighthearted set of entertaining demonstrations at the end of the semster. The “finale” was setting fire to a big hydrogen bubble after “failing” to set fire to a helium bubble. KA-BOOM! Fun. /Insert Mythbusters-style disclaimer here
If you blow the balloon half-full of air first, it makes a hell of a flash/bang, not merely a big sooty fireball!