I like Cleaned Coins and you should to thread

OK, math time, someone check me:
Silver dollar diameter = 38.1mm = 3.81cm
Radius = 1.905cm
Face Area = pr[SUP]2[/SUP] = 11.40 cm[SUP]2[/SUP] X 2 for 2 sides = 22.80 cm[SUP]2[/SUP]
Circumference = pd = 11.97 cm
Thickness = 2.58 mm = 0.258 cm
Area of edge = 11.97 cm X 0.258 cm = 3.09 cm[SUP]2[/SUP]
Total area = 25.89 cm[SUP]2[/SUP]
Thickness of an Ag atom = 144 pm = 144 X 10[SUP]-12[/SUP] m = 144 X 10[SUP]-10[/SUP] cm = 1.44 X 10[SUP]-8[/SUP] cm
Assume we go 100 atoms deep for 1.44 X 10[SUP]-6[/SUP] cm
So: (1.44 X 10[SUP]-6[/SUP] cm)( 25.89 cm[SUP]2[/SUP]) = 0.000037 cm[SUP]3[/SUP]
At a density of 10.49 g/ cm[SUP]3[/SUP] this would be 0.0004 g
Measureable, but just barely so, and this is removing 100 atoms uniformly and assuming they are all touching.

 

Log in or Sign up to hide this ad.

Toning will be visible if you cut in half and your math is likely wrong, not that I have much experience in these matters.

 

Your math is likely wrong? Your math is likely wrong! You can't just say that, prove it or I can just say that you are likely wrong also. (not being mad, just stirring the pot)

 

Toning/Corrosion/Cleaning experiment

I thought it would be interesting to take some moderately new cents (shiny ones) and subject them to a variety of treatments: 1) letting water evaporate from the coin repeatedly
2) letting distilled water evaporate from the coin repeatedly
3) letting acetone evaporate from the coin repeatedly
4) letting xylene evaporate from the coin repeatedly

What do you think? Suggestions

 

It looks copy and pasted to be honest lol

 

You are absolutely right, I did it in Word and copied and pasted it. Much easier to do superscripting and subscripting that way.

 

The galvametric properties of silver would make your assertion impossible. When you look at the Nerst Equations and Voltage potential for silver there is NO WAY your only going to get a few microns of toning.

 

Metal Potential, Volts Metal Potential, Volts
Calcium +2.20 Hydrogen 0.000
Magnesium +1.87 Antimony -0.190
Aluminum +1.30 Arsenic -0.320
Manganese +1.07 Bismuth -0.330
Zinc +0.758 Copper -0.345
Chromium +0.600 Mercury -0.799
Iron +0.441 Silver -0.800
Cadmium +0.398 Platinum -0.863
Nickel +0.220 Gold -1.100

 

http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/electrochem.html

 

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/electpot.html#c1

 

Heavy

I'm not sure what this has to do with film thickness, but don't get so complicated. Try this instead


The metals are ranked in order of being reactive from most to least (nickel should be below iron and above tin).
Interesting in that it shows nickel should be reactive while silver is one of the least reactive. Enough chemistry!

 

Micron = micrometer = 1.0 X 10[SUP]-6[/SUP]m

So, I said 1.44 X 10[SUP]-6[/SUP]cm which is 1.44 X 10[SUP]-8[/SUP]m while the linked article (which actually talks about coins) says 1.0 X 10[SUP]-7[/SUP]m to 5.3 X 10[SUP]-7[/SUP]m, so I appear to be off by an order of magnitude and the max weight loss with equal depth toning over the entire surface of the coin might reach 0.004 g. Interesting article BTW.

http://www.jhonecash.com/research/toning_physics.asp

 

One other thing I noticed from the "Reactivity Series of Metals" chart is how reactive Aluminum is. The reason we can make aluminum coins is that the aluminum metal immediately forms a continuous protective coating of oxide so we really don't have an aluminum surface, but an aluminum oxide surface.

 

why silver batteries then?

 

which is why it is anodized.

 

I'm sorry, but if water or a bit of rubbing alcohol destroys a coin then I don't want it in my collection to begin with. If a coin is that extremely rare and fragile, as a responsible collector, it shouldn't be in my collection either. It should be in a museum where it will be properly preserved.

 

Because the Hunt brothers were trying to collect them....what does this have to do with anything????

 

Anodizing = surface oxidation

 

Which of your coins is anodized?