I Figured out why the Coins look Different
Remember the coin experiment that I performed lately?
When I washed the coins, they looked different.
But why?
I finally figured out the answer.
Copper metal is oxidized by the Ag1+ to Cu2+ and the Ag1+ ions are reduced by the copper metal to silver metal.
But do you remember what the coins are made of?
Penny: The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc) until now. Cents of both compositions appeared in that year.
50 Satang (Thai baht): The core is 99% iron and cladding is 99% Copper.
10 Yen (Japanese Yen): 95% copper, 3–4% zinc, and 1–2% tin.
The Penny turned yellow-orange because the zinc was mixed with copper.
The Thai coin turned darker because of the iron.
The Japanese coin turned yellow because of the zinc and tin. Tin is light yellow and zinc is gray.
I hope you enjoyed that experiment, if you did, comment down below ↓
Sources:
Danupon Drake 
Really? because I think it wasn’t that great…
Those are usually the best posts when you didn’t expect them!
I got this experiment from the silver tree, that experiment uses a copper coil, but I used copper coins like pennies to see if it works. But the coins turned into different colors and I didn’t know what happened. And that lead me to make this post XD
Nice observation! When I was in high school we saved the dimes and fifty cent coins that had a lot of silver in them. Not anymore!..lol
Thank you.
Clever