Tapping table slows the ball??

SloRoller

SloRoller

Stuck in SLO
Silver Member
I find this one really hard to believe.

I recorded the World Cup of Pool (from Wales) on my DVR. Jim Wych and Kim Davenport commentating.

I watched it this morning. Strickland and Morris were playing the Vietnam team. Vietnam was up, one of the players overstroked a ball and tapped the chalk on the rail to tell the ball to stop.

Strickland said something to Morris that he shouldnt tap the the table while the ball is in motion, it will cause the ball to slow down.

Whats surprised me is Kim agreed with him. Jim said its the first time he head heard of that and let it drop.

I gotta call BS on this one. No way tapping the chalk on the rail will have any affect on the ball.

Its a nervous habit by some pool players (ever talk to the ball, swing your arms to get the ball to roll after the stroke etc ..)

This has no affect on the outcome. I cant believe Earl and Kim bought into this.

Has anyone heard of this?

SR
 
I would like to see some actual scientific videos and what not on this issue. Personally I believe that it does have an effect on the cueball and tell the person who pounds his palm on the table multiple times to get it to stop to not do it again. You are sending vibrations onto the table causing an increase in friction between the cloth and cueball making is slow down. That is what I imagine happening, maybe I am wrong. But if it doesn't happen then why do people do it. I don't think your examples of waving the cueball up table and yelling at the ball are good ones since you are having no effect on the ball. A better example would have been knowing that the ball is going to go long, and so you run over to where the ball is coming off the rail and blow as hard as you can on the ball. This would slow it down though not physically touching it.

Again I am no expert. I just don't appreciate someone deliberately trying to affect the outcome of the game by messing with the equipment. Would be like going long and going to the table and lifting one end of the table to get it to slope towards your next ball. Is that covered in the rules, or seen it happen?
 
I can imagine that the ball might possibly slow a little if you repeatedly banged the slate hard. I'm not saying that it DOES have an effect, just that it might. However, if tapping the chalk on the rail slows the ball down, they are playing on the wrong table.
 
UWPoolGod1 said:
.. I believe that it does have an effect on the cueball ... maybe I am wrong...then why do people do it. ?
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C'mon! I thought you learned you some smarts in College! It is like putting pebbles in the path of an oncoming car to slow it down...good luck!

Why do people bang the table? Coz they are mad! And realize that striking it with all their force would likely result in injury!!!!

Hahahaha!
 
I would think that the vibrations would push the ball if they were traveling with the ball. You could prove this by placing a ball on the edge of a pocket. Stand at the far end and tap the table. If the ball drops into the pocket the tapping made the ball move. There is a also a correlation of how hard the table is tapped. :rolleyes:

I think Morris was upset with Earl and didn't want to get into a discussion at that time. I also heard Earl complain that the Filipinos are the luckiest players in the world.

Earl has opinions about many things that affect the game of pool. Some of the recent post of about him at the Derby explain why he does certain things.
 
Slowhand said:
If you attached a heavy duty device to vibrate the table, the ball will roll longer.
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I wonder if you can elaborate on this statement? I'd like to know how you know this, and whether you know why it's true; not because I doubt you, only because I'd genuinely like to know.

Slowhand said:
Even with that being said, I can't see tapping the table with something as light as a piece of chalk having any real effect. And even if it did, it may only be a millimeter or two on an eight rail kick.
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Agreed. These vibrations would HAVE to be entirely negligible in terms of actual distance of CB roll.

-Andrew
 
Of course tapping the table with chalk slows down the ball.

Just like putting a ball in golf, the path of the rolling golf ball on the green can be influenced by the putter leaning his body to one side or the other. By leaning to the left, the player exerts pressure on the green such that the slope of the green changes just enough to modify the path of the rolling ball in that direction. I also think using "body english" in golf shouldn't be allowed as well.

:p
 
Slowhand said:
If you take an object and place it on an inclined plane and then vibrate it, then it will slide. Therefore, vibrations reduce friction. How do vibrations effect avalanches and landslides? Do they slow them down or help to cause them? How about a vibrating sander on a level surface? Does it slide easier when it's on or off? I have never found an example where vibrations have caused something to grip tighter, but I'm sure I can come up with a hundred examples where it makes it move easier.
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The incline plane example and avalanche example are both the same concept, but I don't believe either one applies to a rolling ball. In both cases, you're talking about something that starts out stationary, thus subject to static friction. The vibrations move the surface up and down, and while the surface is on a down-swing, the pressure between the object and surface is decreased. During this period of decreased pressure, gravity overcomes static friction, as we know friction is directly proportional to pressure. Now the object is sliding, and the coefficient of friction at play is no longer the static coefficient, but the dynamic one, which is generally quite significantly lower, and thus does not have the power to stop the object, now that it is moving.

With an already-rolling ball (and by the time you're tapping the rail, the ball will be rolling naturally), neither static friction nor "sliding" of any kind is taking place, and so I think the inclined plane example isn't at all comparable.

Now this is where my physics understanding runs out; I honestly can't figure out whether the vibrations would shorten or lengthen the roll. Does anyone else have an explanation for whether this effect should occur, and why?

-Andrew
 
Andrew Manning said:
Does anyone else have an explanation for whether this effect should occur, and why?
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First and foremost, I am very sceptical that tapping chalk on the rail will cause a rolling ball to slow down more than normal .... BUT .... a serious vibration on the table might cause the rolling ball to bounce on the table, which means the ball would spend part of it's time NOT in contact with the table, thereby reducing the average amount of friction (less friction when the ball is airborne) causing it to roll farther ... which of course is opposite of Earls concern.

Dave
 
DaveK said:
First and foremost, I am very sceptical that tapping chalk on the rail will cause a rolling ball to slow down more than normal .... BUT .... a serious vibration on the table might cause the rolling ball to bounce on the table, which means the ball would spend part of it's time NOT in contact with the table, thereby reducing the average amount of friction (less friction when the ball is airborne) causing it to roll farther ... which of course is opposite of Earls concern.

Dave
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Yeah, I thought about that, but then I thought about how the moments when the CB was contacting the table, it would be under dramatically increased pressure, due to the "bouncing", and I wasn't sure whether these effects would cancel each other out, or whether one would have more effect than the other. Furthermore, even if the CB isn't literally bouncing, the vibration wave would create periods of alternatingly increased and decreased pressure between the ball and the cloth. I'm pretty sure in this case they would cancel each other out, because if the CB's staying in contact with the cloth the whole time, the average pressure during the up and down swings of the vibration should still be the CB's weight. If the CB were leaving the table, that no longer holds true, so in short I'm confused.

-Andrew
 
Laws of motion

A force as small as chalk will not have any effect on the ball.

The vibration would have to create an upward force on the rolling ball that is greater than the downward force at that very moment in order for anything to happen. Downward force is equal to less than the weight of the object since it would be moving laterally. In other words, the ball would have to be bouncing or skipping, where there is no friction at all.

An object moving laterally with no friction or weight will never stop. In this scenario in which we are discussing, the ball should continue to move IF any sort of vibrations on the table were great enough to affect the rolling object.

Please bear with my physics lingo as it has been a while. And I lost my original lengthy post... this is the shortened version. so annoying to have to type that out again.
 
DaveK said:
First and foremost, I am very sceptical that tapping chalk on the rail will cause a rolling ball to slow down more than normal .... BUT .... a serious vibration on the table might cause the rolling ball to bounce on the table, which means the ball would spend part of it's time NOT in contact with the table, thereby reducing the average amount of friction (less friction when the ball is airborne) causing it to roll farther ... which of course is opposite of Earls concern.

Dave
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Earl is correct if HE were too tap the chalk with that 50 pund weight on his arm he might cause the table to flip over therefore causing all the balls to stop rolling and start bouncing
 
I think that Kim was being a little bit sarcastic (at least I HOPE he was). To actually say that a force that small tapping the edge of the table will in any way affect a ball rolling down a table is absolutely LUDICROUS!

Now, if the player took his fist and pounded on the table, then maybe the statement wouldn't be so dumb.

But, I never take anything Earl has to say seriously. He probably thinks that wristpad cures cancer!
 
I was about to do some experimenting on my pool table with a sander and lag shots when I came to my senses and realized that we are talking about Earl here! He always makes up excuses for when bad stuff goes his way. Just like when he complains about being distracted so much. I mean, come on! how many players would make it to pro status if they were so easily distracted?

Vinnie
 
There use to be a rule about patting/bumping the table etc. Not sure if the rule is still written but it did exist. I never gave it much thought but I've seen some slap the bed pretty hard. Another one is pushing on the cloth against the rolling ball which could make a small difference.

Some tables (like bar boxes) are not as solid so it's possible it could have a very minor effect. Even if it made just a millimeter difference, that could mean having a shot or being hooked. Regardless I don't see why players do either, just let the balls roll.

Rod
 
Earl has done it again---My hats off to Earl.

While everyone is thinking about the physics of tapping the table to slow the ball: all Earl wanted to do is get in the opponent's mind by thinking about something else. This is very similiar to asking your opponent if he breathes in or out when on the final stroke.

Asking about the breathing is sharking and could be called a foul. Bringing up a question about a rule is legal---but I'll bet the opponent will think about it for a while.

Remember, Earl has been to the John McEnroe school of "Tricks of the Trade"
 
While I dont claim to be an expert, I have read that 3 cushion Billiard tables are made with much thicker slate because it reduces the vibrations that occur on the surface, and thus allows the ball to roll further and truer. If thats the case, then any vibration on the table, could conceivably make a difference in how far a ball travels. Again, this might be an incredibly small amount when considering the weight of a pool table, but if it even makes a millimeter of a difference, as was said previously, this can make the difference of having or not having a shot.

Also, the last time I read the BCA rules, there was a rule in there about tapping the rail while a ball was in motion being a foul. Ill have to look again in the current rulebook to be sure.

Ultimately, I think it was just Earl being Earl...but tapping the table is still something that should not be done.

JMHO
 
cincyman said:
Earl is correct if HE were too tap the chalk with that 50 pund weight on his arm he might cause the table to flip over therefore causing all the balls to stop rolling and start bouncing
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I'd pay to see that !

Dave
 
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