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B How Did This Guy Make a Soccer Ball Wobble On the Ground?

  1. Jul 31, 2017 #1
    Hello, Hello,

    I found this youtube video that I have been trying to figure out how they did for a while. Being the good men of science that you guys are, I figured you might be able to explain how he did this:

    I tried:
    Filling the ball with water(which worked at slower speeds)
    Over inflating the ball to make it lop sided(which failed)
    Inflating it with soda to see if the co2 emisions would make it more lop sided.


    I want to try:
    putting a nob on the side of the ball
    installing a weight on one side of the ball.
    anything else you guys might have in mind.


    Thanks,

    Jordan Rodgers
     
  2. jcsd
  3. Jul 31, 2017 #2

    fresh_42

    Staff: Mentor

    To me it looks like an extra weight inside the ball. Another possibility would be a ball, which isn't shaped like a sphere, but slightly flattened.
     
  4. Jul 31, 2017 #3
    Okay, I'll test out the weight concept. What do you think is a good way to do that? I was thinking just adding some tape and some quarters to the side of the ball.
     
  5. Jul 31, 2017 #4

    fresh_42

    Staff: Mentor

    The video reminded me on something like this

    where the crucial point is also the non uniform weight distribution. The best way would probably be a metal ball inside the football, which can move from side to side, or two weights hidden inside fixed on opposite sídes. So the key point is the preparation part. Weights outside may help, but the chances are high to end up with a ball that doesn't roll at all.
     
  6. Jul 31, 2017 #5
    Yeah I agree that there is something inside the ball. Here is a picture of the experiment I just tried: https://ibb.co/fkGwvQ

    It did not roll, it popped into the air when it hit the weights. Also, that means the knob on the side of the ball concept can be ruled out.

    The ball has to be round to keep it rolling. So that tells me there is something inside the ball that makes it do that. The only question is what exactly? Perhaps a liquid with a higher viscosity than water like oil to make it slowly change directions from left to right.

    If it is a metal ball, the question is how he got it into the football to begin with?
     
  7. Jul 31, 2017 #6

    fresh_42

    Staff: Mentor

    I don't know. Footballs weren't always manufactured by questionable companies in questionable locations by questionable "employees". A few possibilities among eventually more I can think of: they made the entire ball, they found a place to buy them (store for magicians or similar), or they worked with water and ice. Also liquid lead when the ball was flat is a possibility. Or we should ask Belichik and Brady :wink:
     
  8. Jul 31, 2017 #7

    Okay, let me try the water and freez method. I will get back to you if that worked. I think it will.
     
  9. Jul 31, 2017 #8

    Charles Link

    User Avatar
    Homework Helper

    I don't think they used an ordinary ball. They could have plated it with iron on the inside and had magnets underneath the field. Once it is rolling smoothly for a good period of time, the ball doesn't collectively decide on its own to wobble all over the place.
     
  10. Aug 7, 2017 #9
    The wobbly path of the knuckle ball is well known in football. The novelty of the OP's video is doing it with the ball staying on the ground.

    Look at this video of the top 10 knuckle ball goals, especially the slow motion replays - the balls do wobble their paths. Notice that the best ones are where the ball is not rotating...

     
  11. Aug 7, 2017 #10

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    Doesn't look like this at anytime. Initially after the kick it slides or flies low, once it starts rolling, it starts going left and right.
     
  12. Aug 7, 2017 #11
    Hello, Hello,

    Sorry I haven't gotten back to you guys for a few days. I was out of town. Anyways, the resuts where that the ice got stuck to the inside of the ball. So it was like a roller coaster when the passengers are going upside down but not falling out of there seats. That did not work. It was just like water, it only worked at slower speeds.

    upside-down-roller-coaster-11096133.jpg

    Maybe what he did was he used a sticky spray on one side of the ball so that it would catch on the surface? Or perhaps he put somthing like this inside the ball.

    29CFCE43D653C79B4609C8CBCDCDD29BC793419DD29BC9CB9DD2569C269DC9D25623C6CCDA2656C76693C6339EF0F543.jpg

    Then he just added a stud to the string to keep the black ball inside from moving to far towards the balls shell as it's spinning to keep the weight more centered.
     
  13. Aug 7, 2017 #12
    Did you even watch the video? It's on the ground so then it obviously was not struck on the valve.
     
  14. Aug 7, 2017 #13
    Nobody has noticed the guy walking around with the radio control.
    In the first shot he is to the by the 2nd pillar to left of the pail target.
     
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