LLNL Discovery Museum
Cloud Rings uses a mist generator and a large rubber membrane with a hole in the middle to launch a ring of vapor up to the ceiling. The ring is generated by the friction between the hole's edge and the vapor flowing through the hole, which forms a swirling pattern known as a vortex.
Blow soap bubbles over the center of the exhibit then launch a cloud ring through the bubbles. Note how the bubbles orbit the vortex moving up in the center and down around the edges.
Ask students to make a slow moving cloud ring.
Then have them make a slow ring followed by a fast ring. The fast ring will overtake and collide with the slow one and destroy it.
Hold a hand over the hole and blow a cloud ring. The cloud ring will fall apart before it reaches the ceiling.
Notice the dark donut shaped core in the center of the cloud ring.
The ring is like a tornado vortex curled into a circle "eating its own tail."
Here is a smoke ring blown by Mt. Etna during a volcanic eruption the rings are up to 200 m in diameter.
Coupled Resonant Pendulums
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Scientific Explorations with Paul Doherty
7 March 2006