Watch YouTube user Xraise Cornell create a homemade horizontal vortex ring generator. When a small burst of air is released into a toroidal or poloidal vortex — essentially a spinning donut of water — it shapes the air into its own ring along the water’s trajectory, creating a vortex ring or a bubble ring.

While we have not made this invention (yet), it looks like a lot of fun. Or of course, with a lot of practice, you could try to make them with no materials at all, just like the dolphins do. Just remember to always be safe. Adult supervision is recommended when using tools or trying experiments underwater.

Or if you want to stay dry, try making a homemade vortex cannon with a tightly closed box with a narrow round hole at the end. Watch!

Travel back to Southampton University, England in 1962 as students compete with the Flying Bicycle Airplane vehicle that they spent months building. Bonus: old-timey narration.

Watch more videos about flying in the archives. 

From British Pathé.

Human-powered helicopters, thought-controlled helicopters, and now helicopter-bicycles! From PopSci: 

The helicopter-bike is a prototype developed by a team of three Czech companies, which just took it for a five-minute test flight inside a Prague exhibition hall. That’s actually a lightweight dummy in the driver’s seat, since those massive propellers make this thing weigh over 200 pounds, meaning it’s not yet flyable with the weight of a human on board.

What kind of helicopter do you want to invent?

From PBS Digital Studios’ Inventors, meet Ernest Nussbaum, inventor of the Practicello. Be sure to check out the entire series.

There are more inventions and more instruments on this site, as well as the must-see trailer for the documentary Landfill Harmonic. 

It can be a challenge for some sound-making machines to be understood via video. Sometimes there’s no way to truly understand how it’s working without the experience of playing it. The theremin, patented in 1928 and played above by its Russian inventor Léon Theremin, is one such instrument. 

The controlling section usually consists of two metal antennas which sense the position of the player’s hands and control oscillators for frequency with one hand, and amplitude (volume) with the other, so it can be played without being touched. The electric signals from the theremin are amplified and sent to a loudspeaker.

Still fascinating to watch, however, especially when played by the inventor. This video, and many others are featured in io9’s The Oddest-Looking Musical Instruments on Earth. And/or there are more inventions and instruments in the archives.

Thanks, @philomathia.