A Different Spin

Today a group called A Different Spin came to visit Mudd. They're a fire performing troupe based in Oakland, California. They came last year and we enjoyed it so much that we booked them again this year. They're scheduled for a performance at night (actually half an hour from the time of writing) but even better than that was the workshop that they held in the quad this afternoon. Starting at 13:00 they broke out their toys and started teaching people how to juggle balls and clubs, spin poi and twirl staffs. I learned poi spinning from a junior and senior who taught it as a student-taught PE class my freshman year and really enjoy it. These guys taught me the basics of juggling in about 10 minutes last year even though I had never been able to learn before. This year one of them taught me how to crack a bull whip.

A whip is a really incredible object; I'm going to go into science mode for a few minutes to explain it. If you've ever held a rope, chances are you've laid it on the ground and shaken it up and down to produce a wave that travels along and falls off the end. A whip is exactly that with one extra bit: if you were to tie a light, thin rope to the end of a thicker rope and send a wave along the thicker rope when it hit the thin rope it would continue along, but it would go faster. The equation is v=(F/m)^(0.5) where v is the speed of the wave, F is the tension on the rope, and m is the mass per unit length of the rope. Thus as the rope gets lighter, the wave moves faster. A whip is tapered, so it's constantly getting lighter which means the wave gets faster and faster until it falls off the end. At that point it's traveling along individual fibers teased out of a piece of string tied onto the end called the "cracker". When the wave is on these fibers it's traveling extremely fast and when it falls off the end the cracker breaks the sound barrier and a sonic boom is created.

When you whip a towel you'll find that you need to pull back after you fling it out in order to get it to snap at all. That's because the wave along the towel does not speed up, so you need to pull back to get any speed at the end. A whip does not, and you crack a whip by flicking it straight out in the direction opposite the one it's pointing in -- that creates a kink or loop that propagates down to the end, and if it's tight enough, the whip cracks. Of course, the trick is to get it to crack away from you. I'm slightly embarrassed to say that this was the most fun I've had in a long time with that picture of my arm as evidence. I'm off to the show now, but I'll let you know how it went and how my trip to Ireland last week went in the next few days.

~KMarsh