Population tables. of world cities. This article lists the most populous cities in the world defined according to a concept of city proper. A city proper is a locality defined according to legal or political boundaries and an administratively recognised urban status that is usually characterised by some form of local government. Cities proper and their boundaries and population data may not include suburbs. World Urbanization Prospects, a UN publication, defines population of a city proper as the population living within the admi
The mass of one cubic centimeter of copper is 8.96 grams, while the mass of the same amount of zinc is 7.13 grams. 1  A penny is made of copper and zinc. 2  Copper is heavier than zinc. 3  The cost of copper has been on the rise during the past couple of decades.
Coca-Cola is 0.055% phosphoric acid (this contributes to the zingy taste and fizziness). The phosphoric acid in Coke removes the oxide coat on the pennies, thereby leaving the metal shiny. Remember though that you should NEVER try to clean a collectible coin.Cleaning is OK for ordinary coins you get in change, but chemicals damage the outer surface of a coin and reduce its value if it's collectible.o when calcium and zinc build up on your penny soaking it in coke will eat away at the metals built up, leaving it nice and shiny. Side note: alkaline pH substances eat away at proteins so that's why we use high alkaline products to clean our sinks and toilets. 44 people found this useful.