# The "Ball Under a Foot of Water" Challenge

Note: This thread is 1786 days old. We appreciate that you found this thread instead of starting a new one, but if you plan to post here please make sure it's still relevant. If not, please start a new topic. Thank you!

## Recommended Posts

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.

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

##### Share on other sites

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.

##### Share on other sites

LOL. But I was there.

And I understand basic physics.

##### Share on other sites

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...

##### Share on other sites

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?

##### Share on other sites

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.

##### Share on other sites

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!

##### Share on other sites

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).

##### Share on other sites

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.

##### Share on other sites

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.

##### Share on other sites

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?

##### Share on other sites

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

@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?

##### Share on other sites

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

PayPal.

##### Share on other sites

[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.

I'm in.

I'm in.

I'm in too.

##### Share on other sites

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

##### Share on other sites

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.

##### Share on other sites

Note: This thread is 1786 days old. We appreciate that you found this thread instead of starting a new one, but if you plan to post here please make sure it's still relevant. If not, please start a new topic. Thank you!

## Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

×   Pasted as rich text.   Paste as plain text instead

Only 75 emoji are allowed.

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×

• ### Topics Being Discussed Right Now on The Sand Trap

×
×
• Create New...

## Important Information

Welcome to TST! Signing up is free, and you'll see fewer ads and can talk with fellow golf enthusiasts! By using TST, you agree to our Terms of Use, our Privacy Policy, and our Guidelines.

The popup will be closed in 10 seconds...