Hi team and seasons greetings. Is there a quick and cheap way to test the purity of silver?
I’m on the road so I’ll check back when I get internet next. Thanks

Is this silver ore?

Stan may be away awile…

I don’t understand, ore as compared with what? refined silver?

1. Get the mass of the silver object, beam balance if necessary.

2. Get volume by seeing how much water it displaces, use a marked beaker or some such.

Once you have volume and mass compare it with what it should be if it is pure silver to get it’s actual purity.

Once you have volume and mass compare it with what it should be if it is pure silver to get it’s actual purity.
———————————-

I get 1 and 2…

But the conclusion? How do you allow for what else is hidden, melded, mixed with the silver?

Shirly some stuff will be heavier and some more spacious…

perhaps conductivity could be a quick measure

http://www.sciencecompany.com/How-to-Test-Gold-Silver-and-Other-Precious-Metals-W122.aspx

dunno how you would go getting nitric acid.

Peak Warming Man said:

1. Get the mass of the silver object, beam balance if necessary.

2. Get volume by seeing how much water it displaces, use a marked beaker or some such.

Once you have volume and mass compare it with what it should be if it is pure silver to get it’s actual purity.

Euraka!

don’t make up words sibeen.

ChrispenEvan said:

don’t make up words sibeen.

You scatter the leaves
Euraka the leaves

party_pants said:

ChrispenEvan said:

don’t make up words sibeen.

You scatter the leaves
Euraka the leaves

That’ll do me, I’m going to read.

Try using a laser spectrometer. It analyses the spectrum of a laser beam reflected from the surface to determine the silver content, and also the impurities. It can also analyse the purity of other precious metals (and lots of other stuff.)

Peak Warning Man said:

1. Get the mass of the silver object, beam balance if necessary.

2. Get volume by seeing how much water it displaces, use a marked beaker or some such.

Once you have volume and mass compare it with what it should be if it is pure silver to get it’s actual purity.

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

morrie said:

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

I call shenanigans…
(it’s doing my head in)

Carmen_Sandiego said:

morrie said:

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

I call shenanigans…
(it’s doing my head in)

Got a balance? Place a glass of water on it an immerse your finger tip.

morrie said:

Carmen_Sandiego said:

morrie said:

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

I call shenanigans…
(it’s doing my head in)

Got a balance? Place a glass of water on it an immerse your finger tip.

Methinks a few steps are missing.

Carmen_Sandiego said:

morrie said:

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

I call shenanigans…
(it’s doing my head in)

It would work if the glass is brim full and you let the water spill over and then measure the slightly emptier glass.

Stealth said:

Carmen_Sandiego said:

morrie said:

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

I call shenanigans…
(it’s doing my head in)

It would work if the glass is brim full and you let the water spill over and then measure the slightly emptier glass.

It works. I have used it many times. Its just difficult to understand the physics of it.

Tamb said:

morrie said:

Carmen_Sandiego said:

I call shenanigans…
(it’s doing my head in)

Got a balance? Place a glass of water on it an immerse your finger tip.

Methinks a few steps are missing.

You have the volume of the object
You have the weight of the object
Silver has a consistent weight

Object weight in pure silver
Object weight with impurities

The percentage difference would indicate the purity of the silver object.

Stealth said:

Carmen_Sandiego said:

morrie said:

There is a slightly simpler way of doing this:

1. Suspend the object with the finest possible line.
2. Place a glass of water on a balance and tare it
3. Dip the object into the glass of water, minimising the amount of line immersed.
4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres.Try if it you don’t believe it. :)
5. Measure the weight in the conventional way.

I call shenanigans…
(it’s doing my head in)

It would work if the glass is brim full and you let the water spill over and then measure the slightly emptier glass.

Or simply use a graduated container & note the difference in water levels.

http://eprints.qut.edu.au/19374/3/c19374.pdf

This technique is based on the fact that an object suspended in a liquid displaces a volume of liquid equal to the volume of the object. When an object is suspended in a liquid filled container placed on a balance, the increase in apparent mass divided by the density of the liquid gives the volume of the suspended object. The main difference between this technique and more traditional methods of measuring volume is that the object is suspended in liquid such that the supporting line takes up the excess weight above buoyancy (assuming that the density of the suspended object is greater than the liquid density). The technique presented in this article is a variation on this technique. Instead of measuring an unknown volume using a liquid.

PermeateFree said:

Tamb said:

morrie said:

Got a balance? Place a glass of water on it an immerse your finger tip.

Methinks a few steps are missing.

You have the volume of the object
You have the weight of the object
Silver has a consistent weight

Object weight in pure silver
Object weight with impurities

The percentage difference would indicate the purity of the silver object.

No. By that method you don’t have the volume of the object.
The weight on the balance pan is the same if you put the object on the pan next to the water or in the water unless you measure the weight/volume of displaced water.

Tamb said:

Stealth said:

Carmen_Sandiego said:

I call shenanigans…
(it’s doing my head in)

It would work if the glass is brim full and you let the water spill over and then measure the slightly emptier glass.

Or simply use a graduated container & note the difference in water levels.

Measurement of volume of water in a cylinder is much less accurate than using a balance.

Carmen_Sandiego said:

http://eprints.qut.edu.au/19374/3/c19374.pdf

This technique is based on the fact that an object suspended in a liquid displaces a volume of liquid equal to the volume of the object. When an object is suspended in a liquid filled container placed on a balance, the increase in apparent mass divided by the density of the liquid gives the volume of the suspended object. The main difference between this technique and more traditional methods of measuring volume is that the object is suspended in liquid such that the supporting line takes up the excess weight above buoyancy (assuming that the density of the suspended object is greater than the liquid density). The technique presented in this article is a variation on this technique. Instead of measuring an unknown volume using a liquid.

Ah. Missed step. Line is attached to balance.

Tamb said:

PermeateFree said:

Tamb said:

Methinks a few steps are missing.

You have the volume of the object
You have the weight of the object
Silver has a consistent weight

Object weight in pure silver
Object weight with impurities

The percentage difference would indicate the purity of the silver object.

No. By that method you don’t have the volume of the object.
The weight on the balance pan is the same if you put the object on the pan next to the water or in the water unless you measure the weight/volume of displaced water.

Wrong. Grab bucket, stick it on your bathroom scales and try immersing some objects in it. Things that are non-porous. Test your statement against it.

Tamb said:

Carmen_Sandiego said:

http://eprints.qut.edu.au/19374/3/c19374.pdf

This technique is based on the fact that an object suspended in a liquid displaces a volume of liquid equal to the volume of the object. When an object is suspended in a liquid filled container placed on a balance, the increase in apparent mass divided by the density of the liquid gives the volume of the suspended object. The main difference between this technique and more traditional methods of measuring volume is that the object is suspended in liquid such that the supporting line takes up the excess weight above buoyancy (assuming that the density of the suspended object is greater than the liquid density). The technique presented in this article is a variation on this technique. Instead of measuring an unknown volume using a liquid.

Ah. Missed step. Line is attached to balance.

I was referring to a top loading balance. Line is held in your hand.

Tamb said:

Carmen_Sandiego said:

http://eprints.qut.edu.au/19374/3/c19374.pdf

This technique is based on the fact that an object suspended in a liquid displaces a volume of liquid equal to the volume of the object. When an object is suspended in a liquid filled container placed on a balance, the increase in apparent mass divided by the density of the liquid gives the volume of the suspended object. The main difference between this technique and more traditional methods of measuring volume is that the object is suspended in liquid such that the supporting line takes up the excess weight above buoyancy (assuming that the density of the suspended object is greater than the liquid density). The technique presented in this article is a variation on this technique. Instead of measuring an unknown volume using a liquid.

Ah. Missed step. Line is attached to balance.

Not according to that article.

Carmen_Sandiego said:

Tamb said:

Carmen_Sandiego said:

http://eprints.qut.edu.au/19374/3/c19374.pdf

This technique is based on the fact that an object suspended in a liquid displaces a volume of liquid equal to the volume of the object. When an object is suspended in a liquid filled container placed on a balance, the increase in apparent mass divided by the density of the liquid gives the volume of the suspended object. The main difference between this technique and more traditional methods of measuring volume is that the object is suspended in liquid such that the supporting line takes up the excess weight above buoyancy (assuming that the density of the suspended object is greater than the liquid density). The technique presented in this article is a variation on this technique. Instead of measuring an unknown volume using a liquid.

Ah. Missed step. Line is attached to balance.

Not according to that article.

Yes. I see that now.

morrie said:

Tamb said:

PermeateFree said:

You have the volume of the object
You have the weight of the object
Silver has a consistent weight

Object weight in pure silver
Object weight with impurities

The percentage difference would indicate the purity of the silver object.

No. By that method you don’t have the volume of the object.
The weight on the balance pan is the same if you put the object on the pan next to the water or in the water unless you measure the weight/volume of displaced water.

Wrong. Grab bucket, stick it on your bathroom scales and try immersing some objects in it that are suspended from your hand by a piece of string. Things that are non-porous. Test your statement against it.

fixed

OK. Now I see the method & it looks feasible.

A wine bottle might be a good object to try, as you know its volume, roughly. Makes no difference how full it is except that you have to push it under the surface of the water instead of dipping it. Push it down to some fixed point on the label with the bottle full, then with the bottle half full. Repeat as necessary to verity ;)

the imprecision is strong with this one

waves hand Jedi style

When using the glass of water you need a very accurate balance, a set of kitchen scales is not good enough. Finding a balance that accurate may be difficult. Also be aware of the need to shake off ALL air bubbles that may have adhered to the silver.

Silver pure density 10.49 g/cc
Sterling silver 92.5% silver, 7.5% copper, density 10.2 to 10.3 g/cc
Copper 8.94 g/cc
Aluminium 2.7-2.8 g/cc
Nickel 7.81 g/cc
Pewter 92% tin, 7.5%antimony, 0.5% copper, density 7.28 g/cc
Pyrite 4.8-5 g/cc

mollwollfumble said:

When using the glass of water you need a very accurate balance, a set of kitchen scales is not good enough. Finding a balance that accurate may be difficult. Also be aware of the need to shake off ALL air bubbles that may have adhered to the silver.

Gold or diamond scales are accurate.

roughbarked said:

mollwollfumble said:

When using the glass of water you need a very accurate balance, a set of kitchen scales is not good enough. Finding a balance that accurate may be difficult. Also be aware of the need to shake off ALL air bubbles that may have adhered to the silver.

Gold or diamond scales are accurate.

you can buy some extremely cheap ones these days on the internet, accurate to .002g

morrie said:

you can buy some extremely cheap ones these days on the internet, accurate to .002g

Where?

mollwollfumble said:

morrie said:

you can buy some extremely cheap ones these days on the internet, accurate to .002g

Where?

type gold scales or jewellery scales and add the phrase, accurate scales.. most are .01g accurate. Depending on how large scale is required, they shouldn’t cost more than $2,000 to weigh up to 6 Kg

http://www.lacywest.com/01scales.htm
http://www.esslinger.com/scales.aspx
http://www.scalesgalore.com/tjewel.htm
http://www.oldwillknottscales.com/jewelry-0.1-gram-scales.html
Much less expensive scales may be found on e-bay
http://www.ebay.co.uk/bhp/accurate-scales

http://www.lacywest.com/01scales.htm#gb6001s

> Accurate scales <$2,000

Not what I call “extremely cheap”. But the ebay link looks good, so long as you import them from China or the Czech Republic.

mollwollfumble said:

> Accurate scales <$2,000

Not what I call “extremely cheap”. But the ebay link looks good, so long as you import them from China or the Czech Republic.

THe $2,000 weigh up to 6.1 Kg. the .002g accurate ones are diamond scales that weigh in carats and the maximum is 100 carat or 20g

roughbarked said:

mollwollfumble said:

> Accurate scales <$2,000

Not what I call “extremely cheap”. But the ebay link looks good, so long as you import them from China or the Czech Republic.

THe $2,000 weigh up to 6.1 Kg. the .002g accurate ones are diamond scales that weigh in carats and the maximum is 100 carat or 20g

Can get them even more accurate but they cost more.

Mettler Carat Scale CG1003 – Maximum Capacity 1050 ct

Specially developed for weighing diamonds and precious stones with the highest accuracy, the CG & CG-S Carat Balances are extremely reliable, fast and robust, thanks to MonoBloc technology (CG-S). The interface enables one to connect the balance to any other device. This scale is heated to ensure exact measurement of weights. A must for the highest standards in this segment. Legal for Trade approved by the Canadian Measurment Act requirements.
Mettler Carat Scale CG1003

Specifications

* Maximum Capacity 1050 ct * Readability 0.001 ct * Taring range 0…1050 ct * Repeatability 0.5 mct * Linearity ± 1 mct * Adjustment with internal weights FACT (fully automatic self-calibration) * Adjustment with external weights 50/100/200 g * Sensitivity (temperature drift) ± 2 ppm/°C * Interfaces LocalCAN Universal Interface * Size of weighing pan ø 85 mm * Free height above weighing pan 240 mm * Dimensions 205 × 330 × 310 mm (WxDxH) * Legal for Trade.

560016 Mettler Carat Scale CG1003 $3,450.00

roughbarked said:

roughbarked said:

mollwollfumble said:

> Accurate scales <$2,000

Not what I call “extremely cheap”. But the ebay link looks good, so long as you import them from China or the Czech Republic.

THe $2,000 weigh up to 6.1 Kg. the .002g accurate ones are diamond scales that weigh in carats and the maximum is 100 carat or 20g

Can get them even more accurate but they cost more.

Mettler Carat Scale CG1003 – Maximum Capacity 1050 ct

Specially developed for weighing diamonds and precious stones with the highest accuracy, the CG & CG-S Carat Balances are extremely reliable, fast and robust, thanks to MonoBloc technology (CG-S). The interface enables one to connect the balance to any other device. This scale is heated to ensure exact measurement of weights. A must for the highest standards in this segment. Legal for Trade approved by the Canadian Measurment Act requirements.
Mettler Carat Scale CG1003

Specifications

* Maximum Capacity 1050 ct * Readability 0.001 ct * Taring range 0…1050 ct * Repeatability 0.5 mct * Linearity ± 1 mct * Adjustment with internal weights FACT (fully automatic self-calibration) * Adjustment with external weights 50/100/200 g * Sensitivity (temperature drift) ± 2 ppm/°C * Interfaces LocalCAN Universal Interface * Size of weighing pan ø 85 mm * Free height above weighing pan 240 mm * Dimensions 205 × 330 × 310 mm (WxDxH) * Legal for Trade.

560016 Mettler Carat Scale CG1003 $3,450.00

How much would differences in gravity due to mass density distributions of the earth affect this ? Ie where you put the scale ? How are these scales calibrated?

Dropbear said:

How much would differences in gravity due to mass density distributions of the earth affect this ? Ie where you put the scale ? How are these scales calibrated?

From the answer to everything:

Apparent gravity on the earth’s surface varies by around 0.7%, from 9.7639 m/s2 on the Nevado Huascarán mountain in Peru to 9.8337 m/s2 at the surface of the Arctic Ocean. In large cities, it ranges from 9.766 in Kuala Lumpur, Mexico City, and Singapore to 9.825 in Oslo and Helsinki.

I guess that accurate scales come with an accurate calibration mass, but I don’t know.

you either get with the scales, or buy separate, calibration masses. come in a variety of sizes.

OK, let’s go back to the original use for the scales. From Morrie

> 1. Suspend the object with the finest possible line.
> 2. Place a glass of water on a balance and tare it
> 3. Dip the object into the glass of water, minimising the amount of line immersed.
> 4. Read the reading on the balance in grams. This will be the volume of the object in cubic centimetres. Try if it you don’t believe it. :)
> 5. Measure the weight in the conventional way

Suppose the silver object has a mass of 1 g. Then the mass of water displaced will be about 0.1 g. To get that to 5% accuracy the scales have to be accurate to 0.005 g. This silver object will have a largest dimension of perhaps 2 cm. So the scales will have to accept a maximum weight exceeding 10 g probably, given limited beaker sizes, more than 20 g. For a set of scales capable of measuring more than 20 g to an accuracy of 0.005 g you’re starting to talk about serious money. And even then 5% accuracy isn’t all that good. If the silver object weighs 5 grams and is the same size then a scale accuracy of 0.02 g will do, which is easier to find.

> 1. Get the mass of the silver object, beam balance if necessary.
> 2. Get volume by seeing how much water it displaces, use a marked beaker or some such.
> Once you have volume and mass compare it with what it should be if it is pure silver to get it’s actual purity.

For a 5% accuracy on density of a 1 g mass of silver this way you would need to measure a water level change to an accuracy of 0.01 mm. Practically impossible.

By the way, with a scale similar in appearance to the first on the Lacy West website, I’ve been able to weigh the speed of evaporation of a drop of water. That’s something that needs to be allowed for.

http://www.scalesplus.com.au/

some accurate ones are fairly cheap.

ChrispenEvan said:

you either get with the scales, or buy separate, calibration masses. come in a variety of sizes.

correct.

mollwollfumble said:

By the way, with a scale similar in appearance to the first on the Lacy West website, I’ve been able to weigh the speed of evaporation of a drop of water. That’s something that needs to be allowed for.

indeed.

It would also depend if they are spring scales or balance scales. Balance scales would be largely immune to minor variations in local gravity.
(I think)

morrie said:

Tamb said:

PermeateFree said:

You have the volume of the object
You have the weight of the object
Silver has a consistent weight

Object weight in pure silver
Object weight with impurities

The percentage difference would indicate the purity of the silver object.

No. By that method you don’t have the volume of the object.
The weight on the balance pan is the same if you put the object on the pan next to the water or in the water unless you measure the weight/volume of displaced water.

Wrong. Grab bucket, stick it on your bathroom scales and try immersing some objects in it. Things that are non-porous. Test your statement against it.

The physics isn’t that mysterious.

When you immerse the object it displaces its volume in water, and the force on the string is reduced by the weight of that volume of water. That force has to go somewhere, and it goes through the scales.

So the change in weight on the scales is the weight of the displaced water, which is the same as the volume of the displaced water (in appropriate units).

The Rev Dodgson said:

Apparent gravity on the earth’s surface varies by around 0.7%, from 9.7639 m/s2 on the Nevado Huascarán mountain in Peru to 9.8337 m/s2 at the surface of the Arctic Ocean. In large cities, it ranges from 9.766 in Kuala Lumpur, Mexico City, and Singapore to 9.825 in Oslo and Helsinki.

That’s about right. I weigh noticeably less in Western Australia than I do in London.

For measuring the specific gravity of silver the variation of the Earth’s gravity doesn’t matter because there you’re dividing one weight by another.

Spiny Norman said:

It would also depend if they are spring scales or balance scales. Balance scales would be largely immune to minor variations in local gravity.
(I think)

Unless they were really big :)

The Rev Dodgson said:

Spiny Norman said:

It would also depend if they are spring scales or balance scales. Balance scales would be largely immune to minor variations in local gravity.
(I think)

Unless they were really big :)

The trick when looking for accurate scales of whatever proportion or type, is the phrase •legal for trade•

roughbarked said:

ChrispenEvan said:

you either get with the scales, or buy separate, calibration masses. come in a variety of sizes.

correct.

calibration masses that are accurate to a thousandth of a gram? impressive

Dropbear said:

roughbarked said:

ChrispenEvan said:

you either get with the scales, or buy separate, calibration masses. come in a variety of sizes.

correct.

calibration masses that are accurate to a thousandth of a gram? impressive

legal for trade, if you are talking diamonds.. has to be impressive.

Diamonds are a girls best friend, but scales are not

Dropbear said:

Diamonds are a girls best friend, but scales are not

:)