Roebuck stalking this week

[sako751sg]

Right enough Mark,but if the 10g is from the antler drying and not the skull that would reduce your volume weight surely??I think anyway.

[M ROBSON]

Dave,

 

Volume will never change, it's a set size and unless the antler shrinks or expands (which bone doesn't tend to do), then it will stay the same. Volume is not a measurement of weight, rather the space that something takes up. In this case we just use the weight to calculate it.

 

eg,

 

600g air weight, 400g weight in water = 200cc volume.

 

same head 90 days later,

 

590g air weight, 390g weight in water = 200cc volume.

 

Simples

Edited May 3, 2012 by M ROBSON

[sako751sg]

Agreed Mark,but explain why the first head has very nearly the same volume than the second one which displaces way more water?Surely this method of finding the volume has nothing to do with water displacement,and more to do with the weight of the antler?Im probably wrong,but are you not just subtracting the antler weight from the combined weight and actually if it is then surely the antler losing 10g would affect the "volume".To measure volume properly you need a container with markings to show displacement,so by doing it in water and using weight in any way is surely not giving us the volume?It would be different using a water displacement system as that wouldnt take into consideration the denseness of the antler?Speaking of denseness,im probably totally wrong.

 

Mark,if i put 10g of lead into the antler you are saying that the volume will stay the same by weighing it in water?If you are,im lost and need help.

 

 

Edited May 3, 2012 by sako751sg

[sako751sg]

Mark,please dont reply as ma heid is officially mince and i dont want to think about it anymore.You will be right,although surely it cant be a true reflection of volume as in water dispacement and a formula that should be close to it?

Edited May 3, 2012 by sako751sg

[sako751sg]

Just for interest i have weighed dry and wet weighed a head with two pounds coins on the actual antlers.The weight with them on was dry,500,wet 385.I already had weighed it withoot the coins,and then dipped too withoot the coins to simulate a weight loss of two coins from the antlers and they were dry,480,wet 375 which shows a weight change of 10g,converted to volume and then points which were -3.Even muddier than ever noo.

[M ROBSON]

Hi Dave,

 

Firstly think of volume as a measurement of mass, the space that something takes up. With hard antlers this doesn't change regardless of what they weigh.

 

We just use the weight in air and the weight in water to work out the volume, the difference between the 2.

 

If a head drys out and looses weight in air then the weight in water will also fall by the same amount, so the difference between the 2 weights will still be the same, hense the volume doesn't change.

 

Cheers,

Mark.

[sako751sg]

Hi Dave,

 

Firstly think of volume as a measurement of mass, the space that something takes up. With hard antlers this doesn't change regardless of what they weigh.

 

We just use the weight in air and the weight in water to work out the volume, the difference between the 2.

 

If a head drys out and looses weight in air then the weight in water will also fall by the same amount, so the difference between the 2 weights will still be the same, hense the volume doesn't change.

 

Cheers,

Mark.

 

 

Why would it change the same though Mark?It would surely depend on if the weight that was lost was from the antler or the skull because this method is determind by getting the weight of the antler in water?If i had a skull,and let the antler dry completely but kept the skull soaked in water and worked out the "volume",surely my "volume" would differ than when they are both totally dry as its weight and not proper volume we are getting.I tried it with the coins and the difference was 10g.

By the way,i hated maths and school in general really.

[M ROBSON]

Just for interest i have weighed dry and wet weighed a head with two pounds coins on the actual antlers.The weight with them on was dry,500,wet 385.I already had weighed it withoot the coins,and then dipped too withoot the coins to simulate a weight loss of two coins from the antlers and they were dry,480,wet 375 which shows a weight change of 10g,converted to volume and then points which were -3.Even muddier than ever noo.

 

 

If you put the coins on the antlers and dipped them for volume then you would be working out the volume of the coins + the antlers.

 

To do this properly you would need to dip the head with the coins out of the water, eg on the top jaw by the teeth.

 

Try and think of it this way, a can of Coke will have the same volume regardless of wether it is full, empty or half drank.

Edited May 3, 2012 by M ROBSON

[sako751sg]

If you put the coins on the antlers and dipped them for volume then you would be working out the volume of the coins + the antlers.

 

To do this properly you would need to dip the head with the coins out of the water, eg on the top jaw by the teeth.

 

Try and think of it this way, a can of Coke will have the same volume regardless of wether it is full, empty or half drank.

 

Your getting confused between volume and the CIC method of getting volume which is through weight.Of course the volume of a can is the same no matter the weight,but are you saying the volume of a pound of mince in a Tesco container,or Harrods for those in Essex and Lidl for Cocker3 and a one pound ball of lead would have the same "volume" if you measured it the CIC way?Surely it wouldnt matter where the coins are as we are not measuring water displacement as weight is not used in that.

 

 

I have weighed a wet skulled head,and oot of water it is 510 and in water 385.Ill birstle it on the radiator overnight and see what it weighs tomorrow and see if the difference is the same.

 

At least ma post count is going up nicely today.

 

The quicker a genius comes along and explains to me the better.Apologies if you are one Mark.

Edited May 3, 2012 by sako751sg

[M ROBSON]

Hi Dave,

 

Things don't weigh the same in water as they do in air, as soon as you put the coins in the water you are measuring the volume of the coils along with the antlers.

 

Let me try again, if you have a fresh head that hasn't been dried out there will be moisture in the core of the antler. If you weigh this head it weighs 600g, after 90 days it weighs 500g, so 100g of moisture has eveporated and been replaces by air.

 

If you dip the fresh head, lets say it has a weight of 400g giving it 200cc. The moisture in the antler doesn't weigh anything when it is being dipped because it is neutralised by the fact it is in water.

 

If you dip the 90 day dry head, it will weigh 300g and still have a volume of 200cc. The air in the antler acts as buoyancy and reduces the weight of the head by 100g.

 

I'm no genius by any length, but I've had this very disscussion with Alan Alison in the past and he has measured thousands of heads and if he says it's true then I believe him

 

Cheers,

Mark.

Edited May 3, 2012 by M ROBSON

[cocker3]

LIDL :lol:yer a ***k ALDIS IF YOU DONT MIND mark its no use mate you cant educate pork

[cocker3]

,i hated maths and school in general really.what you went to school thought school stopped during the war anyway

[vulpicide]

A wee guy from Caithness was wondering if you would swap Stalking down your way for some up his way He describes himself as a poor old pensioner but he is a mad stalker in every sense of the word but very en deer ing let me know and if you'r at Scone I'll introduce you anyway. :yp:

[sako751sg]

Aye,and if i hadna been in the Gulf War you would be speaking Iraq gibberish instead of your Weegie gibberish.Dinna thank me Andy,it was nothing. :yp:

[cocker3]

Aye,and if i hadna been in the Gulf War you would be speaking Iraq gibberish instead of your Weegie gibberish.Dinna thank me Andy,it was nothing. :yp:

WEEGIE WEEGIE :blink: :blink:

[sako751sg]

LIDL :lol:yer a ***k ALDIS IF YOU DONT MIND mark its no use mate you cant educate pork

 

Aye you can.I watch a documentary called Peppa Pig and shes on the ball.

 

WEEGIE WEEGIE :blink: :blink:

 

Aye,low blow but just take it.

[sako751sg]

Hi Dave,

 

Things don't weigh the same in water as they do in air, as soon as you put the coins in the water you are measuring the volume of the coils along with the antlers.

 

Let me try again, if you have a fresh head that hasn't been dried out there will be moisture in the core of the antler. If you weigh this head it weighs 600g, after 90 days it weighs 500g, so 100g of moisture has eveporated and been replaces by air.

 

If you dip the fresh head, lets say it has a weight of 400g giving it 200cc. The moisture in the antler doesn't weigh anything when it is being dipped because it is neutralised by the fact it is in water.

 

If you dip the 90 day dry head, it will weigh 300g and still have a volume of 200cc. The air in the antler acts as buoyancy and reduces the weight of the head by 100g.

 

I'm no genius by any length, but I've had this very disscussion with Alan Alison in the past and he has measured thousands of heads and if he says it's true then I believe him

 

Cheers,

Mark.

 

Hi Mark.

Just to put this wee debate to bed.This came from a discussion with a current CIC judge.

If we told a scientist we are getting volume from weighing,they would find it ridiculous as it is just a formula made up as a rough guide instead of actually measuring weight displacement.Forget the meaning of true volume as water dispacement as the method the CIC use as yes,putting coins on the antler would effect true volume but as the CIC is determined by weight then only the scales are affected.Its been confirmed,that the CIC "volume" can change depending on if the skull has lost the weight or if it has come from the antler.Volume of a solid object as you say can never change,but again you are mistaking volume for "volume".

 

If i drilled a hole in one antler on the head,and stuck in 20g of lead and checked the weight,not volume because i would have to measure displacement,and then removed that lead and plugged the hole do you think the CIC "volume" would still be the same?

[M ROBSON]

Hi Dave,

 

Let your fresh head dry out some more then check it's volume and lets see if it's changed. Mind, there will be some variation on how you set up the head in water so best let it dry out a good bit 8-10% to allow for any error.

 

Cheers,

Mark.

[sako751sg]

Your getting confused between volume and the CIC method of getting volume which is through weight.Of course the volume of a can is the same no matter the weight,but are you saying the volume of a pound of mince in a Tesco container,or Harrods for those in Essex and Lidl for Cocker3 and a one pound ball of lead would have the same "volume" if you measured it the CIC way?Surely it wouldnt matter where the coins are as we are not measuring water displacement as weight is not used in that.

 

 

I have weighed a wet skulled head,and oot of water it is 510 and in water 385.Ill birstle it on the radiator overnight and see what it weighs tomorrow and see if the difference is the same.

At least ma post count is going up nicely today.

 

The quicker a genius comes along and explains to me the better.Apologies if you are one Mark.

 

The same heed right now weighs 470 dry but in water the weight shown is now 365.That makes the first "volume" score 37.5 and the second 31.5.This is an extreme scenario because the weight loss has been 40g overnight but shows how it can affect the "volume"depending on where the drying is occuring.Just because Allan has measured thousands of heeds doesnt mean he is correct.It just means he has been scoring to a system consistently and by a book that made up a method of scoring "volume".

 

Simples.

 

Tell me this please Mark,if i drill a hole in an antler,put in 20-30 grams of lead and score it,will it score the same in "volume" when the lead is removed and the hole plugged.And dont say the "volume" will not change because of the mass as the CIC system DOES NOT measure true mass because they dont measure water displaced.

Edited May 4, 2012 by sako751sg

[M ROBSON]

The same heed right now weighs 470 dry but in water the weight shown is now 365.That makes the first "volume" score 37.5 and the second 31.5.This is an extreme scenario because the weight loss has been 40g overnight but shows how it can affect the "volume"depending on where the drying is occuring.Just because Allan has measured thousands of heeds doesnt mean he is correct.It just means he has been scoring to a system consistently and by a book that made up a method of scoring "volume".

 

Simples.

 

Tell me this please Mark,if i drill a hole in an antler,put in 20-30 grams of lead and score it,will it score the same in "volume" when the lead is removed and the hole plugged.And dont say the "volume" will not change because of the mass as the CIC system DOES NOT measure true mass because they dont measure water displaced.

 

Hi Dave,

 

No it won't, simply because you have used lead. The cavity full of air will not cancel out the lead because it is so dense. Also, As I've already said, things don't weigh the same in water as they do in air, 30g of lead in air will weigh less in water.

 

If you put 20-30 grams of water into the antler and then took it out you would have no difference at all to the volume measurement because the same cavity of air can offset the same cavity of water. Water in water has no weight but lead in water does. Air in this same cavity, when under water, will lift the trophy by the same weight as the water that has evaporated, or been removed, from this cavity.

 

The system the CIC use is perfect for the job of measuring their "volume" because the only variables involved in a trophy head are moisture in the bone (water) and air which replaces this moisture when the bone dries out. Everything else stays the same, eg the structure of the antler.

 

Lets just agree to disagree on this one, my good typing finger is getting worn out! We can have a beer at Scone and talk about it some more.

 

Cheers,

Mark.

Edited May 4, 2012 by M ROBSON

[sako751sg]

Hi Dave,

 

No it won't, simply because you have used lead. The cavity full of air will not cancel out the lead because it is so dense. Also, As I've already said, things don't weigh the same in water as they do in air, 30g of lead in air will weigh less in water.

 

If you put 20-30 grams of water into the antler and then took it out you would have no difference at all to the volume measurement because the same cavity of air can offset the same cavity of water. Water in water has no weight. Air in water will lift the trophy by the same weight as the water that has evaporated.

 

The system the CIC use is perfect for the job of measuring their "volume" because the only variables involved in a trophy head are moisture in the bone (water) and air which replaces this moisture when the bone dries out. Everything else stays the same, eg the structure of the antler.

 

Lets just agree to disagree on this one, my good typing finger is getting worn out! We can have a beer at Scone and talk about it some more.

 

Cheers,

Mark.

 

 

What about cheese?Only joking,but I think my measurement of the head today showed a volume change has a occured due to drying.Will have a beer at Scone but please don't mention volume.

[vulpicide]

See me on the SACS stand at Scone and I'll introduce the both of you to the AULD STALKER. :yp:

[sako751sg]

I'll be there fella.

[Cushies]

Hi Mark, i'm not the cleverest but between this thread and speaking to Dave it did my head in, so i called someone that would know, the daughter who's at Columbus Uni. Ohio where she'll graduate as a Prof. in a couple of years time Now we know that the CICs' "VOLUME" has nothing to do with actual volume as we all know it as you cannot measure volume through weight alone, but the weight of a head based on weight measurement in air and water CAN have an effect on the outcome based on the CICs' volume formula.

Please take some time and read the email, it explains everything.

 

 

 

Ok firstly objects will weigh the same in air as they do in water – the way it is measured is different.

In air you can measure it directly i.e on a scale or balance this is effectively the mass of the object + the effect of gravity = weight

The reason for this is as follows - air's density is very small compared to most solids and liquids. For this reason, the weight of an object in air is approximately the same as its true weight in a vacuum. The buoyancy of air is neglected for most objects during a measurement in air because the error is usually insignificant (typically less than 0.1% except for objects of very low average density such as a balloon or light foam).

In water you cannot do a direct weight measurement as buoyancy counteracts gravity. The other fact to consider is density.

“Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object” – Archimedes Principle

This can also be translated as any floating object displaces water equal to its weight whereas a sunken object displaces water equal to its volume.

Water has a density of 1g/ml so effectivly 1g of water = 1ml of water.

However objects that have a density higher than water (i.e lead) will sink and objects that have a density lighter than water will float (i.e feathers/ wood) – this does not change the fact you could have put 10g of feathers or 10g lead into the water – the result will still be 1 will float the other will sink weight will still be the same

If I want to measure weight in water the following equation is required:

Weight = Density x Volume (i.e volume of water displaced)

In this instance both antler and skull are made of bone and will have the same density, however the actual mass of bone may be different – more bone mass in the antlers compared to the skull, this will affect the weight and volume calculated at the end of your 90 day drying period, as both will dry out to varying extents.

You cannot assume that volume will not and does not change.

Again weight is different to volume using the above example 10 g of feathers density 0.3g/ml ; 10g lead density 1.3g/ml

Calculating volume by the above rational:

Feathers Vol = W/D = 10/0.3 = 33 ml

Lead Vol = W/D = 10/1.3 = 7.6 ml

Using the method you have described i.e say I have 600g dry weight and 400g wet weight therefore total volume is 200ccm – THIS IS INCORRECT THIS IS THE DIFFERENCE OF WEIGHT!!!! NOT IT’S VOLUME!!!!

 

The Technical Bit

 

With reference to fluid mechanics, displacement occurs when an object is immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, as in the illustration above, and from this the volume of the immersed object can be deduced (the volume of the immersed object will be exactly equal to the volume of the displaced fluid).

An object that sinks displaces an amount of fluid equal to the object's volume. Thus buoyancy is expressed through Archimedes' principle, which states that the weight of the object is reduced by its volume multiplied by the density of the fluid. If the weight of the object is less than this displaced quantity, the object floats; if more, it sinks. The amount of fluid displaced is directly related (via Archimedes' Principle) to its weight.

In the case of an object that sinks (is totally submerged – not suspended!), the volume of the object is displaced. In the case of an object that floats (as in the case if it is suspended), the amount of fluid displaced will be equal in weight to the displacing object.

In physics, buoyancy is a force exerted by a liquid, gas or other fluid, that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the column than at the top. This difference in pressure results in a net force that tends to accelerate an object upwards. The magnitude of that force is proportional to the difference in the pressure between the top and the bottom of the column, and is also equivalent to the weight of the fluid that would otherwise occupy the column. For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a reference frame which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction. In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body.

 

Dr. Anne-Marie Alexander Bsc(hons)PhD MRSC CCHEM.

Edited May 13, 2012 by Cushies