A neat demonstration of reflectivity

[Slotblog]

I was visiting a cousin in TN this past weekend. He's a rabid coin collector and he showed me something that I thought other Barners might find interesting.

Seems there is a trivial way to differentiate between genuine silver coins and "silver" coins made from clad material, which is what most circulated coins have been made from for a number of decades. Clad material is a three-layer sandwich with outer layers of 75% copper and 25% nickel explosively welded to an inner core of 100% copper.

The pics below show two "slabbed" (encapsulated) Eisenhower dollar coins, one made of silver and one made of clad material. The white material stretched over the coins in the second photo is a common white tissue.

The pics were taken in his den under a daylight lamp. I thought this effect was as definitive a qualitative test as I've ever seen. Seems coin collectors mostly know about this, but it's something I've never stumbled upon before.

The Model A connection? This illustrates why chrome-plated headlamp reflectors don't work as well as silver-plated ones.

 

[Russell in Tulsa]

By Jove, I think you made a valid connection between our "A's" and money that was never mentioned before. Although my wife always said the A and money were connected in another way I don't want to discuss at this time thank you very much.

 

[FrankWest]

I was visiting a cousin in TN this past weekend. He's a rabid coin collector and he showed me something that I thought other Barners might find interesting.

Seems there is a trivial way to differentiate between genuine silver coins and "silver" coins made from clad material, which is what most circulated coins have been made from for a number of decades. Clad material is a three-layer sandwich with outer layers of 75% copper and 25% nickel explosively welded to an inner core on 100% copper.

The pics below show two "slabbed" (encapsulated) Eisenhower dollar coins, one made of silver and one made of clad material. The white material stretched over the coins in the second photo is a common white tissue.

The pics were taken in his den under a daylight lamp. I thought this effect was as definitive a qualitative test as I've ever seen. Seems coin collectors mostly know about this, but it's something I've never stumbled upon before.

The Model A connection? This illustrates why chrome-plated headlamp refelectors don't work as well as silver-plated ones.

That is fantastic!!! The silver almost glows..amazing

So glad you posted this....

Did you know that the color of gold is special because the outer electrons are actually moving at relativistic speeds "close to the speed of light" producing the unique color of Gold!

 

[PepeLoco]

That is fantastic!!! The silver almost glows..amazing

So glad you posted this....

Did you know that the color of gold is special because the outer electrons are actually moving at relativistic speeds "close to the speed of light" producing the unique color of Gold!

Perhaps you are thinking of Cerenkov Radiation? Saw that once during a refueling at a nuc plant.

My sophomoric understanding of the color of gold is due to its absorption and reflectivity of certain wavelengths of electromagnetic radiation which comes in photons, ie.light. The cool thing about light is that it has both wave and particle properties. You can do cool experiments to freak out people. I think it is called a double split experiment? Here it is...
http://www.physicsoftheuniverse.com/topics_quantum_superposition.html

 

[FrankWest]

Yes, but the fact that it absorbs and reflects differently is due to it's relativistic motion " near light speed of electrons in its orbit. Which can be viewed as particles in this case but are really behave as waves in another viewpoint. Again, we do not know what electrons are but are only expressing their behavior in our testing arena.
The fact that light can act like a particle "discrete" or a wave "continuous" Clearly shows use that light is neither. But is something very mysterious.

 

[Slotblog]

This trick was shown to me as the easy way coin collectors determine which coins are made of silver and which are made from clad material.