Could you walk across a swimming pool filled w/ ping pong balls?

  • Thread starter Thread starter AlaskanMatt
  • Start date Start date
  • Tags Tags
    Balls Swimming
AI Thread Summary
A debate arose about whether a person could walk across a swimming pool filled with only ping pong balls. One participant argued that the lightweight and smooth shape of the balls would cause a person to sink, while the other believed the balls would support the weight. The consensus concluded that walking on the balls would be impossible without spreading weight over a larger area, such as using snowshoes. The physics of weight distribution and the properties of the balls were discussed, emphasizing that a person's weight would cause the balls to rise and not provide support. Ultimately, the discussion highlighted the impracticality of walking on a surface of ping pong balls.
AlaskanMatt
Messages
3
Reaction score
0
Hello,

I feel a little out of place here, as I have no physics background whatsoever, but I was hoping you folks here might be able to help settle a debate. My brother and I like to have "what if" discussions, and one we had quite awhile ago was whether a person could walk across a swimming pool filled with ping pong balls (EDIT: No water in the pool, only ping pong balls). :redface:

I said that it would not work, because the balls, being so light and having a smooth sphere shape, would cause a standard person to sink into the balls, and one would have to "wade through" them to get out of the pool.

My brother, however, insists that since the balls would be supported by the sides and bottom of the pool, they would support a person who could easily walk across.

If this is too unscientific of a question feel free to ignore or delete it, but this debate has been going on for quite awhile and I was hoping that someone more experienced in weight/friction/physics issues could explain what would happen better than myself. Thanks for your time,
Matt.
 
Last edited:
Physics news on Phys.org
You are correct, and your brother not so much. Challenge him to walk over ping-pong balls on dry land and see how far he gets. Water just bitches it up a couple of notches.
 
Danger said:
You are correct, and your brother not so much. Challenge him to walk over ping-pong balls on dry land and see how far he gets. Water just bitches it up a couple of notches.

I should have clarified: The pool is full of ping pong balls only, no water involved. But I don't believe either way would work...

Thanks for the response.
 
Yes, you would sink. When you walk, your weight is spread over the area of your feet. Assuming that your foot covers 10 balls and you weigh 150 pounds, each ball is roughly exerting 15 pounds of force in some direction when you take your first step. Since the other balls can't go down, this would result in them rising up around your foot and you would sink.

In order to walk on ping pong balls, you would have to spread your weight over a larger area by using snowshoes or something like that.
 
We could always try looking at Archimedes Principle!
The standard mass of a ping pong ball is 2.7g and its diameter is 40mm
This gives it an effective density of about 0.08 g/cm3
The density of water is 1 g/cm3

Conclude from that what you will.
 
Ball pools wouldn't be much fun if you could walk on the surface!
 
Stonebridge said:
We could always try looking at Archimedes Principle!
The standard mass of a ping pong ball is 2.7g and its diameter is 40mm
This gives it an effective density of about 0.08 g/cm3
The density of water is 1 g/cm3

Conclude from that what you will.

I would think the question is about viscosity, not buoyancy.
 
Well, Matt edited his OP to mention that there was no water involved, but I still think that it can't be done. It would be extremely easy to "float" upon the balls in a horizontal position, but I can't see any way in which one could remain vertical.
 
  • #10
russ_watters said:
Yeah, jeez - have you guys never been to McDonalds?!

Uhhh, no... and why have you? :rolleyes:
 
  • #11
Hurkyl said:
I would think the question is about viscosity, not buoyancy.

Me too. I was being mischievous.
Can you think of a simple order of magnitude calculation involving viscosity of ping pong balls?
 
  • #12
Borg said:
Yes, you would sink. When you walk, your weight is spread over the area of your feet. Assuming that your foot covers 10 balls and you weigh 150 pounds, each ball is roughly exerting 15 pounds of force in some direction when you take your first step. Since the other balls can't go down, this would result in them rising up around your foot and you would sink.

In order to walk on ping pong balls, you would have to spread your weight over a larger area by using snowshoes or something like that.

Exactly! At one point I mentioned to him that unless one was wearing something that made their feet very wide, it would be impossible.

I appreciate the responses everyone. Thanks for your help.
 
  • #13
Any time, pal. Hang around for a while and get into some other neat ****. You strike be as being someone who will be a great PF member.
 

Similar threads

Ping-pong balls, Bernoulli, and water
Replies
5
Views
3K
Buoyancy Force of a Divers "Snorkel" Ping Pong Ball
Replies
1
Views
847
Ping-Pong Ball Submerged in Water and then Released
Replies
12
Views
8K
Bernoulli's Equation with a ping pong ball
Replies
1
Views
4K
Viable Railgun Setup? (ping pong balls)
Replies
10
Views
4K
Behaviour of a ping pong ball dropped in a can full of water.
Replies
1
Views
6K
Help me move a floating bridge 90 degrees w/o getting wet
Replies
15
Views
3K
How Can Bernoulli's Principle Explain a Hovering Ping Pong Ball?
Replies
5
Views
3K
What objects can I use to improve my ball curving skills?
Replies
2
Views
2K
How to compute flexure and failure loads of acrylic sheets
Replies
4
Views
15K

Hot Threads

Recent Insights

Back
Top