# MIT Physics: Spinning Bike Wheel and Conservation of Angular Momentum

When Ryan spins a bike wheel, nothing crazy happens. But something weird happens when he flips it over – watch and learn as he shows and explains why.

# Hydrodynamic Levitation!

On a stream of water you can levitate light balls of all sizes and even disks and cylinders. The mechanism is not the Bernoulli effect…
Want to make this at home:

My friend Blake from InnoVinci emailed me with a cool idea for a video and footage of levitating balls in water streams. Initially it was tough to explain the physics of what was going on. The standard Bernoulli effect relies on the object being completely immersed in the upward-flowing fluid. But in this case the water seems to form a single stream around the object and it’s deflected away and down from the stream. By Newton’s third law, the force on the water by the ball is equal and opposite to the force of the water back on the ball, pushing it up into the stream. There is a stable equilibrium position because if the ball moves into the stream, it “cuts off” the water going over the ball so it drifts out. If it drifts out too far, then lots of water passes over the ball, pushing it back into the stream.

Special thanks to Patreon Supporters:
Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen

Support Veritasium on Patreon: http://ve42.co/patreon

Filmed by Raquel Nuno
Slow motion by Hollywood Special Ops http://hollywoodspecialops.com

# The physics of the “hardest move” in ballet – Arleen Sugano

In the third act of “Swan Lake”, the Black Swan pulls off a seemingly endless series of turns, bobbing up and down on one pointed foot and spinning around and around and around … thirty-two times. How is this move — which is called a fouetté — even possible? Arleen Sugano unravels the physics of this famous ballet move.

Lesson by Arlene Sugano, animation by Dancing Line Productions.