The "Ball Under a Foot of Water" Challenge

[Ernest Jones]

Pretty sure everyone here would gladly send you $10 each if you can demonstrate this. No tricks - we want to see a ball under 1 foot of water a few feet from the shore.

I'm in. @MS256 , do you take Canadian? As many attempts as you care to take, but we get to watch them all.

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FWIW, I don't think you are lying, I think you vastly overestimated the depth and won't admit to that possibility.

[Lihu]

Some back-of-the-envelope math tells me that a golf ball has a maximum density of ~1129 kg/m3. Water, by contrast, is 1000 kg/m3. So golf balls do sink, but just barely, and pretty slowly. That is, the buoyant force very nearly balances out gravity.

Knowing this, we can devise a simple, quick, rough experiment to find out how far a golf ball, moving at a certain speed, can move through water. All you need to do is throw a golf ball downward into water and measure how deep it goes.

Easiest way would be to fill a clear plastic bin to different heights with water. If you hear a thud, you've hit the bottom. Keep filling and throwing until you find the point where there's no thud. Or when you need Tommy John surgery.

Obviously, there are some other simplifications. We're overlooking things like surface tension, lift, that density difference, etc.

I'm not sure how this experiment is supposed to work, because gravity will always pull the ball down to the bottom, eventually.

[iacas]

LOL. But I was there.

And I understand basic physics.

[Ernest Jones]

Quote:

Originally Posted by jamo

Some back-of-the-envelope math tells me that a golf ball has a maximum density of ~1129 kg/m3. Water, by contrast, is 1000 kg/m3. So golf balls do sink, but just barely, and pretty slowly. That is, the buoyant force very nearly balances out gravity.

Knowing this, we can devise a simple, quick, rough experiment to find out how far a golf ball, moving at a certain speed, can move through water. All you need to do is throw a golf ball downward into water and measure how deep it goes.

Easiest way would be to fill a clear plastic bin to different heights with water. If you hear a thud, you've hit the bottom. Keep filling and throwing until you find the point where there's no thud. Or when you need Tommy John surgery.

Obviously, there are some other simplifications. We're overlooking things like surface tension, lift, that density difference, etc.

I'm not sure how this experiment is supposed to work, because gravity will always pull the ball down, eventually.

Dude, really?

The ball won't make a thud from floating down...

[Lihu]

Dude, really?

If you are throwing the ball straight down into a bucket, it seems like the ball will eventually hit bottom. The balls density is still greater than water. Water is virtually incompressible, therefore the ball will always hit bottom.

So, really, I'm not sure how it's supposed to work. Can you explain the details to me?

[jamo]

I'm not sure how this experiment is supposed to work, because gravity will always pull the ball down to the bottom, eventually.

Eventually, of course. But you'd notice a big difference in the speed at which the ball would hit the bottom of the bucket. Hence the changing "thud noises." If there's only an inch or two of water, you'll get a loud noise. If there's a foot and a half, you won't hear much at all. Look, it's not perfect, by clearly people have no clue how far golf ball move through water. It's just a rough estimate.

[Ernest Jones]

Quote:

Originally Posted by Ernest Jones

Dude, really?

If you are throwing the ball straight down into a bucket, it seems like the ball will eventually hit bottom. The balls density is still greater than water. Water is virtually incompressible, therefore the ball will always hit bottom.

So, really, I'm not sure how it's supposed to work. Can you explain the details to me?

I think you'd be able to distinguish between a ball that impacted the bottom of the bucket from the velocity created by the throw and a ball that "eventually hit bottom."

Now pony up your $10 everyone!

[MS256]

Eventually, of course. But you'd notice a big difference in the speed at which the ball would hit the bottom of the bucket. Hence the changing "thud noises."

If there's only an inch or two of water, you'll get a loud noise. If there's a foot and a half, you won't hear much at all.

Look, it's not perfect, by clearly people have no clue how far golf ball move through water. It's just a rough estimate.

For the record (and calculations) it didn't feel like I hit the ball at all. Maybe I did and maybe I didn't but it just felt like I threw a whole lot of water on the green and the ball was in with it (to my surprise).

[Ernest Jones]

Quote:

Originally Posted by jamo

Eventually, of course. But you'd notice a big difference in the speed at which the ball would hit the bottom of the bucket. Hence the changing "thud noises."

If there's only an inch or two of water, you'll get a loud noise. If there's a foot and a half, you won't hear much at all.

Look, it's not perfect, by clearly people have no clue how far golf ball move through water. It's just a rough estimate.

For the record (and calculations) it didn't feel like I hit the ball at all. Maybe I did and maybe I didn't but it just felt like I threw a whole lot of water on the green and the ball was in with it (to my surprise).

Well yeah, I assume the only way to even think of attempting this type of shot is to treat it like an explosion shot out of a bunker or heavy wet rough, but I got $10 sez it wasn't any where near a foot.

[Lihu]

Eventually, of course. But you'd notice a big difference in the speed at which the ball would hit the bottom of the bucket. Hence the changing "thud noises."

If there's only an inch or two of water, you'll get a loud noise. If there's a foot and a half, you won't hear much at all.

Look, it's not perfect, by clearly people have no clue how far golf ball move through water. It's just a rough estimate.

Sure, I get it.

I have a strike plate (a load cell plate with a 1msec response time) and a swimming pool. Presume an air cannon made out of a PVC pipe and compressor would work. I have some proximity detectors that can measure the velocity of the ball before going into the pool, but need to setup a scope to measure the time between pulses.

Not sure if this test is worthwhile or not, because it will take me the better part of a free day to do it. If I can interest my son into doing it this Saturday or Sunday afternoon, then I'll do it.

Let me know if you have any other inputs for this experiment, and I agree that the path of the ball is not known but hoping that the strike plate is big enough for the deeper tests.

[iacas]

Not sure if this test is worthwhile or not, because it will take me the better part of a free day to do it. If I can interest my son into doing it this Saturday or Sunday afternoon, then I'll do it.

It's not.

So, @MS256 , are you going to do it? Because as politely as possible, I'm calling complete and utter BS.

Pretty sure you can make $100+ if you're able to do it. If you fail, we get to assign your avatar and user title for one week for each person who is willing to put up $10 (nothing generally offensive to a typical person).

Who's in?

• @iacas
• @Lihu
• @jamo
• @Golfingdad
• @Shorty
• @Ernest Jones
• @boogielicious
• @cipher

[Lihu]

It's not.

So, @MS256, are you going to do it? Because as politely as possible, I'm calling complete and utter BS.

Pretty sure you can make $100+ if you're able to do it. If you fail, we get to assign your avatar and user title for one week for each person who is willing to put up $10 (nothing generally offensive to a typical person).

Who's in?

@iacas

@Lihu

@jamo

@Golfingdad

@Shorty

@Ernest Jones

@boogielicious

@cipher

Okay, I'm in. How will we wire the money to MS256 if he should be able to do it?

[iacas]

Okay, I'm in. How will we wire the money to MS256 if he should be able to do it?

PayPal.

[Ernest Jones]

[QUOTE name="iacas" url="/t/78113/ms256-vs-physics-10-wagers/18#post_1074632"]   It's not. So, @MS256 , are you going to do it? Because as politely as possible, I'm calling complete and utter BS. Pretty sure you can make $100+ if you're able to do it. If you fail, we get to assign your avatar and user title for one week for each person who is willing to put up $10 (nothing generally offensive to a typical person). Who's in? [LIST] [*] @iacas [*] @Lihu [*] @jamo [*] @Golfingdad [*] @Shorty [*] @Ernest Jones [*] @boogielicious [*] @cipher [/LIST] [/QUOTE] Okay, I'm in. How will we wire the money to MS256 if he should be able to do it?

Easiest way is e-mail money transfer. One of us can act as an escrow or we can just leave to good faith all around. Any non-payers will be tared and feathered. Anyway, I don't see any $$ being paid out.

[cipher]

I'm in.

[JetFan1983]

I'm in.

I'm in too.

[Jakester23]

So what's the over under if he ends up hurting himself swinging hard or falling and ending up completely under water. :)

[iacas]

So what's the over under if he ends up hurting himself swinging hard or falling and ending up completely under water. :)

I don't know. Add your name to the list if you're in.

1. @iacas
2. @Lihu
3. @jamo
4. @Golfingdad
5. @Shorty
6. @Ernest Jones
7. @boogielicious
8. @cipher
9. @JetFan1983
10. You?