Really Rad Riddles and Research (2)

by - 10:16 AM

Riddle me this, riddle me that… A man weighs 148 pounds and must cross a bridge that can only hold 150 pounds; anymore weight would break the bridge and lead to a deathly fall. The man can only make one trip across, but he also has to take three 1 pound balls across with him. He cannot throw any balls across. How can he safely get across?

By juggling!! If the man can continuously keep at least one ball in the air at all time, the force of the weight of the ball wouldn't be exerted onto the bridge. The man would only be exerting 150 pound son the bridge and not 151. Now, granted, this wouldn't actually be possible due to force of momentum of the balls being greater than the force of their weight. But look at all the fun things we can already do with juggling! Riddles! Fun!!!!
https://www.pinterest.com/pin/487373990898150767/

Before the mid-twentieth century, juggling, which comes from the Latin word "joculare" meaning "to jest", was used as a form of entertainment in magic and jest shows. Juggling event dates back to Ancient Egypt, where depictions of women acrobats are found on the wall paintings.
http://juggle3balls.com/2010/10/01/egyptian-jugglers-in-beni-hasan-tomb/

Peter J. Beek and Arthur Lewbel also find the science of juggling very fun! The two movement scientists at the University of Amsterdam suggest the application of juggling in the studies of human movement, robotics, and mathematics. The most evident physical force involved in juggling is gravity. Gravity has a major effect on the number of objects being juggled. Each object must be thrown high enough to allow the juggler time to handle the other balls, which does give the juggler more time but also increases the risk of error.

As the number of objects being juggled increases, the need for speed and height of juggling increases. Although this seems like common sense, I hadn't really considered that I'd be juggling at a faster pace with 4 balls versus 3. It might be too early to say, but I think this will turn out to be a problem for me -I am probably the spazziest person you'll ever meet. But, hey, maybe this will increase my focus and attention to small details! (Hopefully!!!!)
http://www.juggling.org/papers/science-1/

Beek and Lewbel also invented a term that is helpful for jugglers. A dwell ratio is the fraction of time that a hand holds on to a ball between two catches. The larger the dwell ratio, the more time the ball spends in your hand and not in the air. Don't dwell on the past, and don’t dwell on the ball in your hand! Novice jugglers often have larger dwell ratios than professionals, due to their experience and practice. Novice jugglers need more time to make corrections to their hand placement, resulting in larger dwell ratios.
http://www.juggling.org/papers/OJ/

The mass of the objects being juggled also has an effect on the mastery of the skill. Objects with smaller masses are ideal due to the less about of inertia. Inertia is the tendency to resist motion, making smaller amounts of inertia easier to manipulate than larger amounts. More mass = more inertia, so by the laws of science, I predict that juggling three balls will be way easier than the juggling clubs. But we shall see! Another idea that Beek and Lewbel set forth about mass is that juggling objects with an equal mass is easier than different masses. Your brain and hand movements get used to a certain amount of force exerted on each throw and to have to differentiate that between each throw would be very difficult. For now, I don't think this will be a problem I run into, since none of my goals involved juggling objects with different masses.

In regards to human movement, juggling requires optical information to maintain steady pattern. It's pretty obvious that humans can only look at one thing at once; although there are two of them, human eyes can only focus on one thing at a time. This makes juggling hard, because you need to focus on 3 things at the same time. By experimenting with experienced jugglers, Beek discovered that as long as jugglers can see about 100 milliseconds of the flight path of the ball, the can continue to catch and juggle. By just focusing on the arc of the juggle cycles, jugglers are able to move their hands and arms to where the balls will fall.

Beek and Lewbel really cover it all. So far we have discussed their discoveries on physics and human movement. But what about math? They have created an equation that describes the relationship between how long props are in a juggler's hands and how long they are in the air. The equation is as follows.

(F+D)H = (V+D)N

Where…
F is the time a ball spends in the air
D is the time ball spends in hand
H is the number of hands
V is the time a hand is empty
N is the number of balls being juggled

Unless I sprout another hand, H should always be constant. As N (the number of objects being juggled) increases, F and D (the time a ball spends in the air and in the hands) decrease. This is a mathematical expression for what I talked about above: how juggling 4 balls requires more speed than juggling 3 balls.

At first, I wasn’t sure how I would use this equation. It's cool and all but I didn't think it could help me. But then a light bulb went off.
http://craluxlighting.com/lighting/despicable-me-lightbulb-gif.php


As I go from three ball juggling to four ball juggling, I can calculate the exact speed that at which I need to juggle. If I can do this, that I can become more efficient with my skills. I'm really excited to figure this out!! Now all I need to do is start juggling!

I'm nervous that I am not coordinated enough to juggle and after finding this research, I'm worried that I set my goals a little too high. But, hey, you can't fail if you don’t try…?

http://picbear.com/tag/meme2k17

Just kidding!!! I'm actually really excited to use my research to help me juggle. I can't wait to document my progress too!! Stay tuned for next cycle's blog about my beginner's juggling experiences!!
Pce out!
Anna :)

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11 comments

  1. Hi Anna,

    How was your juggling so far? Can you juggle three balls now? I have trouble even juggling two balls, let alone three or fall balls. The mathematics equation is also interesting. It seems like none of the variables match with each other, but at the end it all works out! What are the size of the balls that you plan to juggle? Are there better objects than others (for example, a perfect sphere or a ball slightly longer on one side than the other)? I can't wait to see you juggle 4 balls at once. Good luck!

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    2. Hey Evan!!
      This past week has mostly been research for me, but of course I couldn't resist to pick up three balls and attempt to juggle. Right now, I can juggle 3 balls, but I'll be talking more about my experience with that in my next blog!

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  2. I will warn you from experience, knowing the physics of something may help you less than you think. I wish I could be referring to lock picking but it has more to do with gasoline than lock picking. One of the most effective ways to understand something is to put yourself in a situation where the only way out, is learning the new skill. I've heard it works with languages and I want to try it with lock picking. Also, don't juggle chainsaws, you may have to change the variable H.

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  3. This is a really cool topic! I like how you included the math/physics of your topic instead of just learning how to juggle for seven weeks straight. The science behind it is cool, and it looks like you've made a lot of progress. What is your end goal? What is the hardest type of juggling that you'll be trying to learn? I can't wait to keep up with your blog!

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  4. Thanks so much! I've been really enjoying learning how to juggle! My end goal is to be able to juggle 3 balls, 4 balls, and juggling clubs for 30 seconds straight!

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  5. Hey Anna! All the information sounds super interesting! Now that you've started, does knowing how it works help or does juggling require more of an intuition for it? Also, does the size of the object change the way you throw it or anything? I can't wait to see you juggle four or five balls next! Good luck!!

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    1. If I'm being honest, the science behind juggling hasn't help me too much with the actual skill. Juggling is more of a physical learning type of skill, so once you start doing it, you don't need to know exactly what is happening because it just happens. I think the information is really interesting as well, but it definitely hasn't factored into my juggling as I expected.

      Yes, size/mass of the object plays a really big part in the aspect of time. The larger the mass, the more momentum it will have, which means less time to catch it! I think that's why we typically juggle small items like tennis balls, rather than larger items with more mass. Thanks so much for reading!

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  6. Hi Anna! I had know idea there was so much science behind Juggling! I was just wondering, is it physically demanding to juggle? How long to you typically juggle when you are practicing?

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    1. Hey Ethan! Yes, juggling requires lots of physical and coordination skill. I usually juggle for at least 20 mins each night. The longest I've ever juggled for with no interruptions, however, is about 15 seconds.

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