Using the car exhaust had not worked. The exhaust wasn't very hot in the first place, so why bother?

(Also, as a few readers pointed out, the exhaust gas wasn't just hot nitrogen, it was also made up of heavier molecules, such as CO and CO2.)

Luckily, I already had a good cheap source of air, the pool toy inflator.

For my next experiment, I'd try cold air and hot water. Much as Michael Phelps used cold water to cool the smoke from his weed, I would use hot water to heat the air.

With about one cup of liquid soap added to two pots of very hot water, I dropped my bubble hose into the bucket and switched on the air pump.

A column of bubbles rose straight up. Yes! This was exactly what I was looking for.

In seconds, I walked over to harvest my first blob of flying bubbles. Ideally, I'd have a lightsaber for this, but my breath worked too. I cut off a blob and it flew straight up! I was overjoyed!

There is something really sweet about victory after three or four failed attempts!
Yes! Lighter than air hot air bubbles, pretty easy to create, with super cheap ingredients and not a lot of equipment.

Ever since I worked building displays for the state fair, and probably before, I've had an eye for cheap visual effects. This is a good one. Cheap, lighter than air and practically harmless! Awesome!

In seconds, I walked over to harvest my first blob of flying bubbles. Ideally, I'd have a lightsaber for this, but my breath worked too. I cut off a blob and it flew straight up! I was overjoyed!

There is something really sweet about victory after three or four failed attempts!
Yes! Lighter than air hot air bubbles, pretty easy to create, with super cheap ingredients and not a lot of equipment.

Hot air bubbles were first successful on a cold evening (42 degrees F). The sky was dark so I couldn't tell how high they rose.

Presumably the bubbles flew up for a while, then cooled and fell to the earth. Clumps of bubbles are pretty good insulators though, so it may have taken a while.

Eight or nine big chunks rose up and flew away before the bucket of water cooled down and couldn't make flyers any more.

The water wasn't just cooling because it was a cold night. Blowing all that cold air through it was the main factor.

So, after my big success, I was eager to try it again. The next night I started with genuine boiling water, but the weather was a little warmer and did not have the same lift.

A monsterous clump of bubbles accumulated before finally twisting loose and floating away.

Hot air soap bubbles can work! They make a very eye-catching and fun display using some of the cheapest materials I know. And, did I mention that these hot air soap bubbles will also clothe the sick and feed the homeless? THEY ARE AWESOME!!

I can't wait to show these off in front of a bunch of kids.

I really hope some other people try making flying bubbles, because they really are neat and surprisingly straightforward to create.

Remember to take pictures and always weigh down the air hose in the bucket before you put the boiling water in!