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TornLabrum
07-18-2003, 09:10 AM
Originally posted by gosox41
But it was the humidity's fault, at least that was the excuse Farmer used last night on the radio.

Bob

A little chemistry and physics for Farmio:

The density of air is less with high humidity, and the ball travels farther.

It works this way: The mass of the average moleucle of air is about 29 amu. The mass of a water molecule is 18 amu. The air is not confined to a container, so it expands as gases are added. Therefore, the mass of the water lowers the mass of the air in any given volume. That's less resistance to the motion of the ball.

KingXerxes
07-18-2003, 09:42 AM
Labrum - Thank you for posting that.

It amazes me that these guys spout off about how the humidity is keeping things IN the park, and they couldn't be more wrong. It makes you wonder what else they're wrong about.

Speaking of the broadcast, am I the only one who has noticed that Darrin Jackson is developing an annoying knack of incorporating wishful thinking into factual reporting (ala a used car salesman). As an example, last night after Crede's home run, he says something to the effect of:

"Well there you go, Joe Crede - if he gets that stroke back to where we all think it can be - has filled in another big piece of the puzzle which will allow this team to catch Kansas City in this division."

What the hell is he talking about?

TornLabrum
07-18-2003, 09:47 AM
Originally posted by KingXerxes
Labrum - Thank you for posting that.

It amazes me that these guys spout off about how the humidity is keeping things IN the park, and they couldn't be more wrong. It makes you wonder what else they're wrong about.

Speaking of the broadcast, am I the only one who has noticed that Darrin Jackson is developing an annoying knack of incorporating wishful thinking into factual reporting (ala a used car salesman). As an example, last night after Crede's home run, he says something to the effect of:

"Well there you go, Joe Crede - if he gets that stroke back to where we all think it can be - has filled in another big piece of the puzzle which will allow this team to catch Kansas City in this division."

What the hell is he talking about?

The other one I like is Steve Stone talking about balls "picking up speed" (in violation of the laws of motion) when they bounce of the infield dirt.

As far as Jackson is concerned, don't dismay. Darrin doesn't know what he's saying either.

Paulwny
07-18-2003, 10:04 AM
Originally posted by TornLabrum
A little chemistry and physics for Farmio:

The density of air is less with high humidity, and the ball travels farther.



Absolutely

The only player/announcer I've ever heard agree and argue about a ball traveling further in humid conditions was Phil Rizzuto.

dougs78
07-18-2003, 10:45 AM
Originally posted by TornLabrum
A little chemistry and physics for Farmio:

The density of air is less with high humidity, and the ball travels farther.

It works this way: The mass of the average moleucle of air is about 29 amu. The mass of a water molecule is 18 amu. The air is not confined to a container, so it expands as gases are added. Therefore, the mass of the water lowers the mass of the air in any given volume. That's less resistance to the motion of the ball.

Forigive me for what may be a stupid question, as I have not taken chemistry or physics since high school (thank god).

If the mass of a water molecule is less than the mass of an average molecule of air, then shouldn't that mean it would be easier for anything to move underwater than in air??

My point being, that if what you say is true, then should a baseball launched with the same velocity underwater actually maintain its velocity longer than the same ball launched in air?

If I go underwater and try to move my arm, i feel much more resistance than I do if I'm standing on the pool deck.

Please help explain this apparent anomoly in my subjective experience.

voodoochile
07-18-2003, 10:52 AM
Originally posted by TornLabrum
A little chemistry and physics for Farmio:

The density of air is less with high humidity, and the ball travels farther.

It works this way: The mass of the average moleucle of air is about 29 amu. The mass of a water molecule is 18 amu. The air is not confined to a container, so it expands as gases are added. Therefore, the mass of the water lowers the mass of the air in any given volume. That's less resistance to the motion of the ball.

I did not know that, but it does explain why clouds are normally WAY up in the air...

voodoochile
07-18-2003, 10:53 AM
Originally posted by dougs78
Forigive me for what may be a stupid question, as I have not taken chemistry or physics since high school (thank god).

If the mass of a water molecule is less than the mass of an average molecule of air, then shouldn't that mean it would be easier for anything to move underwater than in air??

My point being, that if what you say is true, then should a baseball launched with the same velocity underwater actually maintain its velocity longer than the same ball launched in air?

If I go underwater and try to move my arm, i feel much more resistance than I do if I'm standing on the pool deck.

Please help explain this apparent anomoly in my subjective experience.

You are not taking into account the difference in density between a fluid and a gas. Fluids by definition have more tightly packed molecules than gasses do.

dougs78
07-18-2003, 11:01 AM
Originally posted by voodoochile
You are not taking into account the difference in density between a fluid and a gas. Fluids by definition have more tightly packed molecules than gasses do.


True. But again to clarify this, the density of water vapor and average air molecules are also the same?

This whole thing just seems so counterintuitive that I'm having a hard time accepting it.

voodoochile
07-18-2003, 11:04 AM
Originally posted by dougs78
True. But again to clarify this, the density of water vapor and average air molecules are also the same?

This whole thing just seems so counterintuitive that I'm having a hard time accepting it.

The difference in density from gas to gas is miniscule compared to the difference in density between liquid and gas. I don't know the rest of it.

Clouds float way up in the air even though they appear to be much denser than the air we cannot see. If they were that much denser, they would sink.

duke of dorwood
07-18-2003, 11:22 AM
Balls always carry better in Atlanta and Houston, 2 very humid areas. Those guys should know that just from being in the game.

Paulwny
07-18-2003, 12:05 PM
Originally posted by dougs78
Forigive me for what may be a stupid question, as I have not taken chemistry or physics since high school (thank god).

If the mass of a water molecule is less than the mass of an average molecule of air, then shouldn't that mean it would be easier for anything to move underwater than in air??

My point being, that if what you say is true, then should a baseball launched with the same velocity underwater actually maintain its velocity longer than the same ball launched in air?

If I go underwater and try to move my arm, i feel much more resistance than I do if I'm standing on the pool deck.

Please help explain this apparent anomoly in my subjective experience.



It has to do with the atomic weight of the water molecule.

This article explains it a lot better then I could, from USA Today:

Humidity and air density
Most people who haven't studied physics or chemistry find it hard to believe that humid air is lighter, or less dense, than dry air. How can the air become lighter if we add water vapor to it?

Scientists have known this for a long time. The first was Isaac Newton, who stated that humid air is less dense than dry air in 1717 in his book, Optics. But, other scientists didn't generally understand this until later in that century.

To see why humid air is less dense than dry air, we need to turn to one of the laws of nature the Italian physicist Amadeo Avogadro discovered in the early 1800s. In simple terms, he found that a fixed volume of gas, say one cubic meter, at the same temperature and pressure, would always have the same number of molecules no matter what gas is in the container. Most beginning chemistry books explain how this works.

Imagine a cubic foot of perfectly dry air. It contains about 78% nitrogen molecules, which each have an atomic weight of 28. Another 21% of the air is oxygen, with each molecule having an atomic weight of 32. The final one percent is a mixture of other gases, which we won't worry about. Molecules are free to move in and out of our cubic foot of air. What Avogadro discovered leads us to conclude that if we added water vapor molecules to our cubic foot of air, some of the nitrogen and oxygen molecules would leave remember, the total number of molecules in our cubic foot of air stays the same. The water molecules that replace nitrogen or oxygen have an atomic weight of 18. This is lighter than both nitrogen and oxygen. In other words, replacing nitrogen and oxygen with water vapor decreases the weight of the air in the cubic foot; that is, it's density decreases.

Wait a minute, you might say, "I know water's heavier than air." True, liquid water is heavier, or more dense, than air. But, the water that makes the air humid isn't liquid. It's water vapor, which is a gas that is lighter than nitrogen or oxygen.

Compared to the differences made by temperature and air pressure, humidity has a small effect on the air's density. But, humid air is lighter than dry air at the same temperature and pressure.


--------------------------------------------------------------------------------

maurice
07-18-2003, 02:03 PM
Originally posted by Paulwny
humid air is lighter than dry air at the same temperature and pressure.

Also, humid air resides in low pressure fronts, while sunny days are caused by high pressure fronts.

soxrme
07-18-2003, 05:02 PM
This board is truly amazing, answers on weather, humidity, air density, and white elephants all in one day. You do not get this on any other baseball sight. Kudos to all! :gulp:

Gumshoe
07-18-2003, 05:17 PM
Is barometric pressure independent of humidity on a given day? I ask because most people that have changeups or such pitches that work better when the pressure is higher (or breaking ball pitchers), I wonder.

One thing is true: Lower temperatures contribute to slower pitches, because air density is greater. Vice verca is true as well. So fastball pitchers want to be in hot, high altitude cities, and breaking ball pitchers the exact opposite.

TornLabrum
07-18-2003, 05:20 PM
Originally posted by duke of dorwood
Balls always carry better in Atlanta and Houston, 2 very humid areas. Those guys should know that just from being in the game.

Also two very hot areas, heat causes air to expand making it less dense. In the case of Atlanta, I think until Denver came into the NL, it had the highest altitude of any city in MLB. Air pressure is less at higher altitudes, meaning that air is also less dense.

hose
07-18-2003, 06:34 PM
Originally posted by TornLabrum
A little chemistry and physics for Farmio:

The density of air is less with high humidity, and the ball travels farther.

It works this way: The mass of the average moleucle of air is about 29 amu. The mass of a water molecule is 18 amu. The air is not confined to a container, so it expands as gases are added. Therefore, the mass of the water lowers the mass of the air in any given volume. That's less resistance to the motion of the ball.



:hawk

"I love when you analyze"

Dadawg_77
07-18-2003, 06:48 PM
Question would make up of the air effect different types of hits in different ways? With the wind blowing against the ball, would lighter air help a line drive and heavier air help a pop up? Thinking since the line shot should have more force in, the wind would have a lesser effect then a slower moving ball.

voodoochile
07-18-2003, 07:17 PM
Originally posted by Dadawg_77
Question would make up of the air effect different types of hits in different ways? With the wind blowing against the ball, would lighter air help a line drive and heavier air help a pop up? Thinking since the line shot should have more force in, the wind would have a lesser effect then a slower moving ball.

Denser, heavier air always creates more friction. Thus more drag. So in either case, it will cause the ball to travel a shorter distance in whatever direction it is moving.

The line drive thing brings up another interesting physical fact (at least to me). If you take a pitching machine that throws a perfectly straight ball (parallel to the ground) and at the same time a "pitch" is "thrown" from the machine, release a suspended ball straight down (with no aided momentum) from the same height as the thrown ball, both balls will hit the ground at the same time. Thus, line drives only travel further if they have an upward angle to them.

Jurr
07-18-2003, 10:46 PM
Ooooohhh...I love it when you guys wax scientific. I'm a biology graduate, and I'd love to give you another scientific explanation for the Sox' woes this year. It will involve my new area of expertise, the dental realm. See, back in 2000, Jerry liked candy. He ate it all the time, and he could...he was manager of the year, dammit!!!! The sucrose formed a substrate for s.mutans, the acidogenic bacteria of the mouth. A cavity (caries) started in one of the teeth of Jerry, and he didn't do anything about it. The infection spread through enamel, dentin, and into the pulp. Down the pulp the infection spread, finally causing a pulpitis and an abcess. These infectious microorganisms, making their way out of the tooth, found the blood stream, looking for another way to cause some damage. Obviously, these organisms crossed the blood-brain barrier, traveled up to the brain, and mentally handicapped the skipper. This lead to constant tinkering, and the new symptoms such as putting a 250 pound homerun hitter in the two hole and Frank Thomas at DH, regardless of the fact that he bats one hundred percentage points better at first. Until Jerry undergoes a regimen of vancomycin to alleviate the meningeal infection, we're doomed! If Jerry would've brushed his teeth and sought dental care, we would all be very happy!!!!!!!

Paulwny
07-19-2003, 10:51 AM
Originally posted by Gumshoe


One thing is true: Lower temperatures contribute to slower pitches, because air density is greater. Vice verca is true as well. So fastball pitchers want to be in hot, high altitude cities, and breaking ball pitchers the exact opposite.

This is true however, if the temp is too low a curve ball pitcher has trouble obtaining a proper feel of the ball. This is when the home plate umpire allows pitchers to blow on their throwing hand.

dougs78
07-19-2003, 11:02 AM
This has been quite the informative thread. I would have never guessed this in 1000 years. Thanks again for clarifying what has to be a very commonly held misconception. Its now safely tucked away in my brain for future reference.


btw....with this new information, I guess I should start looking for tee times on humid days....ugh

xil357
07-19-2003, 11:11 AM
Originally posted by TornLabrum
Also two very hot areas, heat causes air to expand making it less dense. In the case of Atlanta, I think until Denver came into the NL, it had the highest altitude of any city in MLB. Air pressure is less at higher altitudes, meaning that air is also less dense.

Which is part of the reason why Atlanta's old Fulton County Stadium was at times known as "The Launching Pad," right?

Chicago is one of the higher altitude MLB cities as well, right? (That is, in comparison, to cities on the East and West Coasts and even cities along Great Lakes that are lower in elevation than Lake Michigan such as Toronto and Cleveland, or along rivers closer to the mouths of the rivers like Cincinnati, St. Louis and Kansas City, right?)

So with short fences (especially in the power alleys), a Sandberg basket and rising / lower-pressure air that is heated during many, many more day baseball games, the Urinal especially is going to be more conducive to the hitting of more home runs, right?

TornLabrum
07-19-2003, 02:44 PM
Originally posted by xil357
Which is part of the reason why Atlanta's old Fulton County Stadium was at times known as "The Launching Pad," right?

Chicago is one of the higher altitude MLB cities as well, right? (That is, in comparison, to cities on the East and West Coasts and even cities along Great Lakes that are lower in elevation than Lake Michigan such as Toronto and Cleveland, or along rivers closer to the mouths of the rivers like Cincinnati, St. Louis and Kansas City, right?)

So with short fences (especially in the power alleys), a Sandberg basket and rising / lower-pressure air that is heated during many, many more day baseball games, the Urinal especially is going to be more conducive to the hitting of more home runs, right?

At least in the summer months when the wind isn't blowing in off the lake.

Fridaythe13thJason
07-19-2003, 03:06 PM
Originally posted by xil357
Which is part of the reason why Atlanta's old Fulton County Stadium was at times known as "The Launching Pad," right?

Chicago is one of the higher altitude MLB cities as well, right? (That is, in comparison, to cities on the East and West Coasts and even cities along Great Lakes that are lower in elevation than Lake Michigan such as Toronto and Cleveland, or along rivers closer to the mouths of the rivers like Cincinnati, St. Louis and Kansas City, right?)

So with short fences (especially in the power alleys), a Sandberg basket and rising / lower-pressure air that is heated during many, many more day baseball games, the Urinal especially is going to be more conducive to the hitting of more home runs, right?

Well, I'm pretty sure the highest point in Cook Co. is 14 Feet above sea level, and I'm no scientist, but I hope that coastal cities are not below sea level, so I doubt that that is correct.

But I was a Writing major, so I'm not so hip to the science.

TornLabrum
07-19-2003, 03:08 PM
Originally posted by SoCalUIC
Well, I'm pretty sure the highest point in Cook Co. is 14 Feet above sea level, and I'm no scientist, but I hope that coastal cities are not below sea level, so I doubt that that is correct.

But I was a Writing major, so I'm not so hip to the science.

I don't know the exact elevations, but most of northeastern Illinois is somewhere between 500 and 600 feet above sea level.

voodoochile
07-19-2003, 03:16 PM
Originally posted by dougs78
btw....with this new information, I guess I should start looking for tee times on humid days....ugh

Thanks for ruining my day... My hearing aids can't take the humidity... sigh... I guess I'll never hit the ball like Tiger... :D:

Fridaythe13thJason
07-19-2003, 03:16 PM
Originally posted by TornLabrum
I don't know the exact elevations, but most of northeastern Illinois is somewhere between 500 and 600 feet above sea level.

You are 100% correct. 578 is the mean in Chicago. This is a weird feeling. I have never before believed something my whole life to be true, and only to find out I was so wrong. I don't know where I found that info, but I have been saying it for years. Lord, this is a sad day. Thanks for the info.

voodoochile
07-19-2003, 03:19 PM
Originally posted by SoCalUIC
You are 100% correct. 578 is the mean in Chicago. This is a weird feeling. I have never before believed something my whole life to be true, and only to find out I was so wrong. I don't know where I found that info, but I have been saying it for years. Lord, this is a sad day. Thanks for the info.

It is shocking and doesn't come intuitiviely, especially since Chicago is at the souther tip of a huge glacial basin. Anyone who has ever driven across the northern part of Indiana can confirm the definite sense of driving slowly down a long hill.

Daver
07-20-2003, 05:28 PM
Originally posted by SoCalUIC
Well, I'm pretty sure the highest point in Cook Co. is 14 Feet above sea level, and I'm no scientist, but I hope that coastal cities are not below sea level, so I doubt that that is correct.

But I was a Writing major, so I'm not so hip to the science.

You may have that confused with Lake level,the Permenant Puddle is around 450 feet above sea level.

Both Houston and New Orleans are partially below sea level BTW.

TornLabrum
07-20-2003, 06:14 PM
Originally posted by daver
You may have that confused with Lake level,the Permenant Puddle is around 450 feet above sea level.

Both Houston and New Orleans are partially below sea level BTW.

And death valley is a couple of hundred feet below sea level, iirc.

doublem23
07-20-2003, 07:12 PM
Originally posted by SoCalUIC
You are 100% correct. 578 is the mean in Chicago. This is a weird feeling. I have never before believed something my whole life to be true, and only to find out I was so wrong. I don't know where I found that info, but I have been saying it for years. Lord, this is a sad day. Thanks for the info.

Probably that Chicago is only a couple of feet above the lake's normal level. Freshwater lakes have to be elevated so that there can be a system of drainage; otherwise they would just turn into inland salt lakes.

ode to veeck
02-28-2004, 03:28 PM
Woah, I missed this thread last summer, but the propeller headed side of my brain got intrigued by it during that 1st cup of morning coffee today after bouncing here from the current Kittle roof shot thread on Lip's link.

I noted a couple of things, but also came up with some more questions on this topic:

Voodoo notes there is a distinct difference in density between fluids and gases as the atoms are much more closely packed in a fluid. Actually, gases and liquids are both different forms of fluids, while if you replace the word fluid with liquid in Voodoo's description its accurate. Atoms in a liquid phase are like closely packed right on top of each other, but able to slide past each other, unlike a solid where they are mostly fixed.

Clouds are actually made of condensed water droplets, i.e. small liquid H20 particles. They are typically at higher altitudes (though not always) as the condensation point is a function of temperature and the lower temperatures of higher altitudes meaning there's typically a strata above where clouds are forming on the conditions of a given day due to differential temperatures (mostly). All clouds are actually falling, in that water droplets, being a liquid and more dense than air, are falling out the bottom of all clouds. Most of the time, this is not reaching the ground, but when it does, does so typically as rain.

Getting back to the resistance of a baseball in flight as a function of humidity. I think the arguments about density of the humid vs non-humid air were all valid, i.e. more humid air is generally less dense than less humid air due to the average molecular weight difference. If the baseball's traveling in a pure gas, these might be the whole story and the conclusion baseballs travel further in humid air might be entirely accurate.

However, my questions relate to conditions when not all the H20 is present as a gas, i.e. when there is some condensation or liquid form of H20 present. This would occur in any conditions where relative humidity is approaching 100%. Most of the time, "hazy" conditions are due to primarily H20 content in the air, including typically some water droplets (liquid), not just vapor (gaseous).

What are the physics of the resistance to a baseball in flight in air that contains some liquid H20 droplets or particles? Is sometimes high humidity air heavier than dry air due to some portion of water droplets in the volume? How does the resistance at the surface of a baseball behave with respect to gas plus droplets vs the pure gas medium?

Thinking more on this, does the presssure front of a traveling baseball cause an increase in the volumetric density of water droplets at the surface of resistance, due to the differential pressure? Would the higher pressure of the pressure front increase the liklihood of condensation, especially in fairly humid air, possibly increasing the density of droplets in the immediate path of a baseball under some conditions? Conceivably, this might be happening across a range of temperatures and "heavier" humidities at which baseballs sometimes travel.

I have no idea what these answers to my questions are, whether they remotely relate at all to atmospheric conditions in the presence of a baseball traveling in very humid air or whether I'm instead just lost in the vikadin haze from my knee surgery yesterday ... maybe someone more knowledgeable on this topic could further comment on these queries or the actual physics and quantitative details further ...

Paulwny
02-28-2004, 03:46 PM
Originally posted by ode to veeck

What are the physics of the resistance to a baseball in flight in air that contains some liquid H20 droplets or particles? Is sometimes high humidity air heavier than dry air due to some portion of water droplets in the volume? How does the resistance at the surface of a baseball behave with respect to gas plus droplets vs the pure gas medium?


Water can be vaporized until a high humidity of nearly 100 percent is reached. At this point, the density and thus the drag will have been reduced by somewhat less than 1percent compared to dry air. (A temperature increase of about 5 degrees Fahrenheit or an increase in altitude of 300 feet would accomplish the same thing.) Adding more water to the fully moist air would lead to formation of droplets which, by their high density, would start to counter and finally reverse the gains achieved by the initial humidification. Fog, rain, particulates, and hail would certainly reduce the distance traveled.

http://www.weatherwise.org/qr/qry.humidball.html

ode to veeck
02-28-2004, 04:09 PM
Paulwny,

Interpreting this quantitiative information here, i.e. that at its maxima, the increase in air density and drag forces of fully humid air vs dry air is only 1% , the pragmatic engineer in me might conclude the actual impact is nearly meaningless, i.e. it's in the noise range of all other factors and variables.

I'm interpretting (off the cuff) that 1% to mean that like even in a perfectly controlled experiment comparing two nearly identically hit baseballs (if you could even do this) might result in a distance traveled delta of a couple of feet or so.

Again, I'm reading that 1% value as in the noise margin, kinda like a 98 vs 97 MPH fastball, whereas a 93 vs 98 MPH fastball is an entirely different story ...

TheRockinMT
02-28-2004, 04:27 PM
What?

SoxEd
02-28-2004, 04:49 PM
Perhaps another reason humidity is a factor in baseball performance is the increased player discomfort it brings, making it harder to concentrate fully on your best pitching/hitting?

I do know that in Cricket, the bowlers can always 'swing' the ball better on overcast or humid days than on sunny or dry ones.

Of course, the 1% difference in air density may be just enough to tip some boundary-layer effect over its threshhold into action and cause the ball to move more in the air - we need an aerodynamicist/expert on fluid flow to answer this for sure though.

Rex Hudler
02-28-2004, 04:53 PM
Originally posted by duke of dorwood
Balls always carry better in Atlanta and Houston, 2 very humid areas. Those guys should know that just from being in the game.

Then what the heck is Birmingham's problems, because the ball certainly doesn't carry there. LOL

Science was never my strong suit so I am not about to argue this point, but humid air sure feels heavier. I'm sure the science guys can me out here......

Paulwny
02-28-2004, 04:58 PM
The more I've looked into this the more confused I've become.
The following was found:
1-- Humidity increases distance
2-- Humidity has little to no effect on distance, as Ode To Veeck has noted
3--The gain in distance by humidity is negated by the increase in the wt. of the baseballs , they absorb moisture on humid days.
I've decided noone really knows.

voodoochile
02-28-2004, 05:05 PM
Originally posted by Paulwny
The more I've looked into this the more confused I've become.
The following was found:
1-- Humidity increases distance
2-- Humidity has little to no effect on distance, as Ode To Veeck has noted
3--The gain in distance by humidity is negated by the increase in the wt. of the baseballs , they absorb moisture on humid days.
I've decided noone really knows.

There's surely a turnover point where the increased weight perfectly counters the effect of the lighter air, but as has been noted, the effect is in the order of a few feet, so it really isn't much of an effect.

ode to veeck
02-28-2004, 05:27 PM
On the other hand, I remember when the physicists of the 50s and 60s claimed (based mostly on a lot of paper analyses) that curve balls were actually an optical illusion and hardly curved at all, when in fact today there's substantially better camera data to show in fact curve balls really move A LOT.

Empirical evidence in the case of "identical flights" of baseballs across various temp and humidity ranges would be much harder to get, but I'll bet it we might actually learn something of the truth of the matter that might have escaped all of the detailed analysis to date.

At this point, I might be inclined to reach a similar conclusion as Palwny does above "no one really knows".

TornLabrum
02-28-2004, 07:05 PM
Originally posted by ode to veeck
On the other hand, I remember when the physicists of the 50s and 60s claimed (based mostly on a lot of paper analyses) that curve balls were actually an optical illusion and hardly curved at all, when in fact today there's substantially better camera data to show in fact curve balls really move A LOT.

Empirical evidence in the case of "identical flights" of baseballs across various temp and humidity ranges would be much harder to get, but I'll bet it we might actually learn something of the truth of the matter that might have escaped all of the detailed analysis to date.

At this point, I might be inclined to reach a similar conclusion as Palwny does above "no one really knows".

I doubt if any physicist acquainted with Bernoulli's prinicple (and that would be anyone with a high school education) would say a spinning ball doesn't curve. I'd guess that story would be something akin to an urban legend since Bernoulli was born in 1700 and died in 1782.

In fact the only reference I've seen to anything related to this is that Life Magazine one "scientifically proved" a curve ball doesn't curve.

As far as the general argument goes, there are at least three factors that would affect the lenght of flight of identically hit balls: temperature, humidity, and altitude. So we can safely say this much: balls travel best at Coors Field on hot, humid days.

voodoochile
02-28-2004, 07:23 PM
Originally posted by TornLabrum
I doubt if any physicist acquainted with Bernoulli's prinicple (and that would be anyone with a high school education) would say a spinning ball doesn't curve. I'd guess that story would be something akin to an urban legend since Bernoulli was born in 1700 and died in 1782.

In fact the only reference I've seen to anything related to this is that Life Magazine one "scientifically proved" a curve ball doesn't curve.

As far as the general argument goes, there are at least three factors that would affect the lenght of flight of identically hit balls: temperature, humidity, and altitude. So we can safely say this much: balls travel best at Coors Field on hot, humid days.

I remember seeing old footage of tests they did in a wind tunnel to prove a curve ball does curve. So someone felt the need to record the fact at sometime since the invention of TV...

TornLabrum
02-28-2004, 08:38 PM
Originally posted by voodoochile
I remember seeing old footage of tests they did in a wind tunnel to prove a curve ball does curve. So someone felt the need to record the fact at sometime since the invention of TV...

Paul G. Hewitt, who wrote the textbook Conceptual Physics tells the story of reporters who told Robert Goddard, who pretty much was the father of rocketry, that a rocket couldn't fly because to the moon because it wouldn't have any air to push against. Apparently the reporters weren't acquainted with Newton's third law of motion.

So I have no doubt that once they had the wind tunnels, somebody might demonstrate it to the flat earth types. They might also have done it to determine if their were any other factors such as turbulence created by the rotating ball's stitches, etc.

voodoochile
02-28-2004, 10:18 PM
Originally posted by TornLabrum
Paul G. Hewitt, who wrote the textbook Conceptual Physics tells the story of reporters who told Robert Goddard, who pretty much was the father of rocketry, that a rocket couldn't fly because to the moon because it wouldn't have any air to push against. Apparently the reporters weren't acquainted with Newton's third law of motion.

So I have no doubt that once they had the wind tunnels, somebody might demonstrate it to the flat earth types. They might also have done it to determine if their were any other factors such as turbulence created by the rotating ball's stitches, etc.

That was my thought. There is always some yahoo who doesn't want to believe it so they do something to show it is true. Remember the video of the two objects falling on the moon: feather and (I want to say) hammer proving that gravity affects all objects equally regardless of weight and the rest is caused by friction and wind currents.

Of course then again, there are still millions of people who don't believe the human race has ever landed on the Moon.

TornLabrum
02-28-2004, 11:37 PM
Originally posted by voodoochile
That was my thought. There is always some yahoo who doesn't want to believe it so they do something to show it is true. Remember the video of the two objects falling on the moon: feather and (I want to say) hammer proving that gravity affects all objects equally regardless of weight and the rest is caused by friction and wind currents.

Of course then again, there are still millions of people who don't believe the human race has ever landed on the Moon.

Well, that feather could have been made of lead. But that doesn't explain why they fell slower than they would have on Earth, does it?

Most of my freshman physical science students come into high school thinking that if they were on the moon, they'd be weightless.

wassagstdu
02-29-2004, 11:42 AM
Originally posted by Paulwny
The more I've looked into this the more confused I've become.
The following was found:
1-- Humidity increases distance
2-- Humidity has little to no effect on distance, as Ode To Veeck has noted
3--The gain in distance by humidity is negated by the increase in the wt. of the baseballs , they absorb moisture on humid days.
I've decided noone really knows.

I think this is the answer (nodoby knows). My guess is that point #3 is the dominant effect. It is not just the weight but also the elasticity of the cover and yarn in a "humid" ball. But it depends on how and where the balls are stored, because it will take more than a few hours to change the humidity inside the ball. (Remember the Detroit oven and the Comiskey refrigerator some years back?).

As for the ball picking up speed in the infield, that is because of top-spin: rotational kinetic energy is converted to translational energy (speed) when the spinning ball hits the ground. No violation of the laws of physics.

Anyone remember Billy Pierce on Ed Sullivan's TV show (or some show like that) throwing a curve ball into the camera to settle that issue?

TornLabrum
02-29-2004, 12:14 PM
Originally posted by wassagstdu
I think this is the answer (nodoby knows). My guess is that point #3 is the dominant effect. It is not just the weight but also the elasticity of the cover and yarn in a "humid" ball. But it depends on how and where the balls are stored, because it will take more than a few hours to change the humidity inside the ball. (Remember the Detroit oven and the Comiskey refrigerator some years back?).

As for the ball picking up speed in the infield, that is because of top-spin: rotational kinetic energy is converted to translational energy (speed) when the spinning ball hits the ground. No violation of the laws of physics.

Anyone remember Billy Pierce on Ed Sullivan's TV show (or some show like that) throwing a curve ball into the camera to settle that issue?

You're wrong about a batted ball picking up speed. From the Mad Science web site:

http://www.madsci.org/posts/archives/jun99/928860654.Ph.r.html

Here's a link dealing with heat, humidity, and length of batted balls:

http://www.madsci.org/posts/archives/oct2000/971111345.Ph.r.html

ode to veeck
02-29-2004, 12:30 PM
As far as the general argument goes, there are at least three factors that would affect the lenght of flight of identically hit balls: temperature, humidity, and altitude. So we can safely say this much: balls travel best at Coors Field on hot, humid days.

If the '86 quantitative analysis from Palwny's reference's (Peter Freymuth, a professor in the department of Aerospace Engineering Sciences at the University of Colorado in Boulder) is reasonably accurate, the maximun effect humidity has on air density is 1%. I'd rate it a non-factor, whereas I'll wager the
effects of temperature and altitude are much stronger (anyone know how much).

I'd restate the above as balls travel best at Coors on hot days, they also travel real well playing outdoors in Phoenix in the summer, and if JR decided to move the Sox to Albuquerque where its also a mile high and tends to be pretty darn hot in the summer, Frank might be able to hit a bizillion HRs to end his career.

Aside: I got stuck in Phoenix a few years back on a biz trip when the official temp reached 123F and the tarmac at Sky Harbor was like 140 or 150F, well above the air density tables (used to set lean vs rish of fuel mix) they had at the time. They had to close the airport that day. They have a more extensive set of tables now.

On the other hand, the worst hitting park (rated by avg air density, not park dimensions) might be PacBell park when the fog rolls in (sea level = max density due to altitude, fog = darn colder in the bay area, fog = water droplets in the air), making Barry Bonds record shattering slugging percentage even more amazing (if there's no juice involved). Even when the fog's not in, I'll wager Pac Bell's evening games are generally the coolest (temp wise) of parks just about at sea level. Samuel Clemens' quote on the coldest he'd been was the summer he spent in SF comes to mind.

voodoochile
02-29-2004, 12:51 PM
I'm curious about the effects of heat/cold on how far the ball travels.

On the one hand it seems like colder balls would fly further (denser objects travel farther) and colder bats would drive the ball harder for the same reason, but cold air should be denser than hot air (am I wrong here?) which would increase friction and reduce distance traveled.

What about barometric pressure? Playing under a high pressure system might cause the ball to travel shorter distances because by definition there are more gas particles to travel through olver the same period, thus increasing friction.

So, what's the story?

TornLabrum
02-29-2004, 01:07 PM
Originally posted by voodoochile
I'm curious about the effects of heat/cold on how far the ball travels.

On the one hand it seems like colder balls would fly further (denser objects travel farther) and colder bats would drive the ball harder for the same reason, but cold air should be denser than hot air (am I wrong here?) which would increase friction and reduce distance traveled.

What about barometric pressure? Playing under a high pressure system might cause the ball to travel shorter distances because by definition there are more gas particles to travel through olver the same period, thus increasing friction.

So, what's the story?

We've pretty much summed up everything here: the combination that makes balls travel farther are those that make the air less dense: temperature (a big factor between early April and July/August), high humidity, and altitude (the greatest factor I'd say, when you're comparing coastal sea-level towns to Denver).

Paulwny
02-29-2004, 01:16 PM
Originally posted by voodoochile
I'm curious about the effects of heat/cold on how far the ball travels.

On the one hand it seems like colder balls would fly further (denser objects travel farther) and colder bats would drive the ball harder for the same reason, but cold air should be denser than hot air (am I wrong here?) which would increase friction and reduce distance traveled.



A colder ball will have a lower coefficient of restitution (COR) (bounce/spring/elasticity) which is a measure of its ability to retain kinetic energy after a collision. A lower coefficient of restitution will result in more energy loss at contact, and therefore less distance travelled by a batted ball. Conversely, a warmer ball will have a higher COR. Adair reports that a batted ball that would go 375 feet at 70 oF will travel 3 feet farther for every 10oF increase in temperature and will travel 3 feet less for every 10oF drop in temperature. Remember this the ball's temperature. It will take some time for the ball to achieve ambient temperature.
http://www.madsci.org/posts/archives/jan2000/949096006.Ph.r.html

ode to veeck
02-29-2004, 01:17 PM
I'm curious about the effects of heat/cold on how far the ball travels. <...>
colder balls <...>
barometric pressure <...>

The effect of a colder baseball would more likely be due to dimensional differences (colder = smaller in general) of the materials in the ball, than due to the interaction or resistance of a colder vs warmer ball with the air through which it travels. A smaller baseball would have less resistance and travel farther. I would guess the dimensional differences of a baseball over the temp range and its subsequent effect on air resistance would be small (<1%), but I could be wrong.

The effect of barometric pressure would be directly relatable to air density. Higher pressure = denser (slower) air. In the range of generally observed air pressure (~29-31 inches), this might be significant. I'd guess it might be a couple of % or so, but then again, I'm too lazy or groggy this morning to plug in some numbers and don't know for sure.

ode to veeck
02-29-2004, 01:26 PM
Paulwny's right, the elasticity of a colder ball is likely a dominant factor, given two identical swings with the same bat. I was thinking of the trajectory of the ball with the same initial velocity.

Rex Hudler
02-29-2004, 04:12 PM
Originally posted by TornLabrum
We've pretty much summed up everything here: the combination that makes balls travel farther are those that make the air less dense: temperature (a big factor between early April and July/August), high humidity, and altitude (the greatest factor I'd say, when you're comparing coastal sea-level towns to Denver).

Help me out here then..... Why does the ball not carry at all in Birmingham where it is extremely hot and humid? What other factors could be involved?

Daver
02-29-2004, 04:28 PM
Originally posted by Rex Hudler
Help me out here then..... Why does the ball not carry at all in Birmingham where it is extremely hot and humid? What other factors could be involved?

Birmingham is very close to be at sea level,therfore it is subject to the full effect of air pressure,as opposed to Denver,which is a mile above sea level.

Rex Hudler
02-29-2004, 04:30 PM
Originally posted by Daver
Birmingham is very close to be at sea level,therfore it is subject to the full effect of air pressure,as opposed to Denver,which is a mile above sea level.

The ball always carried in Atlanta. Birmingham is between 600 and 1200 feet above sea level, so I wouldn't call that low. But even if elevation were the reason, does that mean elevation is much more important than temperature and humidity?

I'm confused. LOL

wassagstdu
02-29-2004, 04:43 PM
Originally posted by TornLabrum
You're wrong about a batted ball picking up speed. From the Mad Science web site:

http://www.madsci.org/posts/archives/jun99/928860654.Ph.r.html

Here's a link dealing with heat, humidity, and length of batted balls:

http://www.madsci.org/posts/archives/oct2000/971111345.Ph.r.html

The madsci link doesn't contradict the concept of a top-spinning ball picking up speed, which anyone who has ever played ping-pong is well familiar with. It just seems to say baseballs don't get much topspin. With the prevalent uppercut swing these days I think ping-pong one-hoppers (as opposed to two- or three-hoppers the madsci piece seems to be addressing) are not so uncommon.

TornLabrum
02-29-2004, 05:02 PM
Originally posted by Rex Hudler
The ball always carried in Atlanta. Birmingham is between 600 and 1200 feet above sea level, so I wouldn't call that low. But even if elevation were the reason, does that mean elevation is much more important than temperature and humidity?

I'm confused. LOL

I think you've got it, actually. Here are the things you need to keep in mind:

Boyle's law relates pressure to volume, but pressure and density are both directly related to the concentration of gas molecules. If you cut the cut the pressure in half, you double the volume if temperature is constant. For practical purposes in the atmosphere, as you go up, the pressure drops. It does so because the molecules are farther apart because there is less atmospheric weight pushing down on them.

Just to give you an idea of what that means, the average barometric pressure at sea level is 30 inches of mercury. In this area it is closer to 29 inches of mercury. (The barometer readings you see on TV weather forecasts are adjusted to sea level based on our elevation.) At an altitude of 11 km (around 40,000 feet or so, if I'm doing the math right--and I'm doing it in my head), you're already above half of the air in the atmosphere.

Now Denver is only about 1/8 of that altitude, but that still puts a good fraction of the atmosphere below it, so the pressure is quite low. Low enough for water to boil at a considerably lower temperature than 212 degrees, so you have to have special cooking/baking instructions there.

So by far, the elevation of the ball park probably has the greatest effect.

Heat also has a noticeable effect, too. Between April nights and August afternoons, the temperature varies by close to 60 degrees. According to Charles' law, the volume of a gas at constant pressure varies directly with the absolute temperature. It works out to be a change of 1/273 of the original volume for each change of 1 kelvin. So assuming two games in the same ball park in which you have that 60 degree difference but the same barometer reading, that translates into about 30 kelvins and about a 10% volume difference. So the density would be significantly less, too. (I really hope this math in my head is accurate!)

As far as humidity is concerned, the addition of those water molecules (molecular mass 18.0) to the air (molecular mass about 29) will decrease the density. How much water vapor the atmosphere can hold varies with temperature, but I think water vapor normally makes up a pretty small percentage of the total gas in the atmosphere, even when the humidity is high.

So the effect of humidity is probably the least of all of the effects, but since I don't have the numbers, and I left my calculator at work, I'm not prepared to do any crunching.

TornLabrum
02-29-2004, 05:05 PM
Originally posted by wassagstdu
The madsci link doesn't contradict the concept of a top-spinning ball picking up speed, which anyone who has ever played ping-pong is well familiar with. It just seems to say baseballs don't get much topspin. With the prevalent uppercut swing these days I think ping-pong one-hoppers (as opposed to two- or three-hoppers the madsci piece seems to be addressing) are not so uncommon.

The friction with the ground is partially dependent on the weight of the ball. Now I don't think you're going to argue with me that the amount of friction overcoming any topspin effect is gonna be a helluva lot greater for a baseball, due to its weight, than a ping pong ball, which has a weight next to nothing in comparison.

So until I can see any argument from a reputable physicist to the contrary, I'm going with the MadSci explanation. Batted baseballs don't pick up speed when they bounce.

Daver
02-29-2004, 05:07 PM
There you have it.

I am not going to argue with Torn,he teaches physics,and I am just a redneck.

:bandance:

Rex Hudler
02-29-2004, 06:09 PM
Originally posted by TornLabrum
I think you've got it, actually. Here are the things you need to keep in mind:

Boyle's law relates pressure to volume, but pressure and density are both directly related to the concentration of gas molecules. If you cut the cut the pressure in half, you double the volume if temperature is constant. For practical purposes in the atmosphere, as you go up, the pressure drops. It does so because the molecules are farther apart because there is less atmospheric weight pushing down on them.

Just to give you an idea of what that means, the average barometric pressure at sea level is 30 inches of mercury. In this area it is closer to 29 inches of mercury. (The barometer readings you see on TV weather forecasts are adjusted to sea level based on our elevation.) At an altitude of 11 km (around 40,000 feet or so, if I'm doing the math right--and I'm doing it in my head), you're already above half of the air in the atmosphere.

Now Denver is only about 1/8 of that altitude, but that still puts a good fraction of the atmosphere below it, so the pressure is quite low. Low enough for water to boil at a considerably lower temperature than 212 degrees, so you have to have special cooking/baking instructions there.

So by far, the elevation of the ball park probably has the greatest effect.

Heat also has a noticeable effect, too. Between April nights and August afternoons, the temperature varies by close to 60 degrees. According to Charles' law, the volume of a gas at constant pressure varies directly with the absolute temperature. It works out to be a change of 1/273 of the original volume for each change of 1 kelvin. So assuming two games in the same ball park in which you have that 60 degree difference but the same barometer reading, that translates into about 30 kelvins and about a 10% volume difference. So the density would be significantly less, too. (I really hope this math in my head is accurate!)

As far as humidity is concerned, the addition of those water molecules (molecular mass 18.0) to the air (molecular mass about 29) will decrease the density. How much water vapor the atmosphere can hold varies with temperature, but I think water vapor normally makes up a pretty small percentage of the total gas in the atmosphere, even when the humidity is high.

So the effect of humidity is probably the least of all of the effects, but since I don't have the numbers, and I left my calculator at work, I'm not prepared to do any crunching.

English, please?? The question isn't why the ball carries better in Denver than Birmingham , but why does the ball seem to not carry at all here. Could it simply be the location of the ballpark within the area? Could it be the ballpark is surrounded by trees? I have seen a lot of baseball in a lot of parks, and the ball carries as bad at the Hoover Met than anywhere else I have seen.

Remember, when talking science and math to me, type S-L-O-W-L-Y. :)

Gracias

TornLabrum
02-29-2004, 07:17 PM
Originally posted by Rex Hudler
English, please?? The question isn't why the ball carries better in Denver than Birmingham , but why does the ball seem to not carry at all here. Could it simply be the location of the ballpark within the area? Could it be the ballpark is surrounded by trees? I have seen a lot of baseball in a lot of parks, and the ball carries as bad at the Hoover Met than anywhere else I have seen.

Remember, when talking science and math to me, type S-L-O-W-L-Y. :)

Gracias

Could have something to do with the design of the ball park. Does the wind blow in a lot? Is there very little breeze there? Do they freeze their baseballs? Do they have lousy power hitters? Since I've never been to their ball park, I have no idea.

Rex Hudler
02-29-2004, 08:19 PM
Originally posted by TornLabrum
Could have something to do with the design of the ball park. Does the wind blow in a lot? Is there very little breeze there? Do they freeze their baseballs? Do they have lousy power hitters? Since I've never been to their ball park, I have no idea.

Doubt the baseballs are frozen, doesn't seem to be much wind flow at all most of the time, lousy power hitters could be part of it, but even the ones they have had lose HR's.

The ballpark is big (385 to both gaps) so that cuts down on HR's. But I am talking about something different. Balls hit between the gaps just seem to die out there. They look like they are hit better than the way then end up in an OF's glove on the warning track, if they even get there.

In some ballparks, the ball just doesn't carry well. Of course, if you hit it real good, it won't matter. It just seems like that ballpark is worse than most others in that regard.

Daver
02-29-2004, 08:28 PM
Originally posted by Rex Hudler
Doubt the baseballs are frozen, doesn't seem to be much wind flow at all most of the time, lousy power hitters could be part of it, but even the ones they have had lose HR's.

The ballpark is big (385 to both gaps) so that cuts down on HR's. But I am talking about something different. Balls hit between the gaps just seem to die out there. They look like they are hit better than the way then end up in an OF's glove on the warning track, if they even get there.

In some ballparks, the ball just doesn't carry well. Of course, if you hit it real good, it won't matter. It just seems like that ballpark is worse than most others in that regard.

You basically just described Old Comiskey Park,a magical place where flyballs went to die.

TornLabrum
02-29-2004, 10:38 PM
Originally posted by Daver
You basically just described Old Comiskey Park,a magical place where flyballs went to die.

And a lot of that had to do with the configuration of the ball park's effect on air currents. The new ball park is a whole lot different.

maurice
03-01-2004, 12:38 PM
Originally posted by TornLabrum
The friction with the ground is partially dependent on the weight of the ball.

It also has to do with the surface the ball strikes. There's a BIG difference between a ping-pong table and the grass (or even the dirt) at the Cell.

This discussion reminds me that many (most?) baseball players believe: (1) that good changeups actually start off at fastball speed and then suddenly slow down before they reach the plate; and (2) that good, overhand, four-seam fastballs actually rise as they approach the plate.

voodoochile
03-01-2004, 01:17 PM
Originally posted by maurice
It also has to do with the surface the ball strikes. There's a BIG difference between a ping-pong table and the grass (or even the dirt) at the Cell.

This discussion reminds me that many (most?) baseball players believe: (1) that good changeups actually start off at fastball speed and then suddenly slow down before they reach the plate; and (2) that good, overhand, four-seam fastballs actually rise as they approach the plate.

Fastballs don't rise unless you throw them upwards. That would lead to a ball that would probably hit the backstop given the average height of pitchers and the fact that they are already elevated above the level of the rest of the infield.

It is physically impossible for a ball to gain speed after it leaves the pitchers hand. The fastest it is traveling is immediately upon release. For it to rise, it would have to gain speed.

What the batters are responding to is a very fast pitch which doesn't sink as much as slower ones, and as a result throws off their swing. They swing under it and figure the ball must have gone up. In reality, it has to do with coordination and the ways our bodies react. Great athletes are conditioned to do things based on expected results and the fact that their reflexes allow them to swing at a pitch that will be at a different height than when it crosses the plate and have success is exactly why they are such great athletes.

Paulwny
03-01-2004, 02:23 PM
Any opinions on the cross-eye dominent theory as it pertains to hitting ?