What is the purpose of the density of pennies lab?
What is the purpose of the ‘density of pennies’ lab activity? The purpose is to compare the densities of pennies minted before 1982 and after 1983. Also, it’s to identify the metal used in the core of pennies minted after 1983.
Why do pennies have different densities?
Copper over Zinc In 1982, the US government solved the problem by making pennies mostly of zinc, a cheaper metal, with a thin coating of copper to make it look like a penny. Zinc’s lower density means these pennies are lighter, though not as light as pure zinc.
What do you learn from a density lab?
The determination of density is a nondestructive physical process for distinguishing one substance from another. Density is the ratio of a substance’s mass to its own volume. In this experiment you will determine the density of several liquids and compare the physical properties of those liquids.
What variable changed in the density of pennies?
In 1982, the U.S. penny composition changed from 95% copper and 5% zinc to 97.5% zinc and 2.5% copper. Since copper is considerably more dense than zinc, the net mass of the penny dropped at that time.
Why did the composition of pennies change after 1982?
The cent’s composition was changed in 1982 because the value of the copper in the coin started to rise above one cent. Some 1982 pennies used the 97.5% zinc composition, while others used the 95% copper composition.
What is the true density of a penny?
Given the densities and compositions of the pure metals, pennies minted between 1962 and 1981 (old) have a density of 8.83 g/cm3. Pennies minted after 1983 (new) have a density of 7.18 g/cm3.
Do pennies have different densities?
The mass of a penny has changed significantly whenever the metals that make up the penny have been changed. Different metals change the mass of a penny because they have different densities. Two pennies that are approximately the same size but which have different densities will have different masses.
Why is density so important what does it tell us?
Density is calculated as the mass of an object divided by its volume (d = m/V). Density is an important concept because it allows us to determine what substances will float and what substances will sink when placed in a liquid.
How do you explain density to a child?
Density measures the mass of an object or substance compared to its volume. The equation we use to find density is: density = mass / volume. If an object is heavy and compact, it has a high density. If an object is light and takes up a lot of space, it has a low density.
Does the average density of a penny change before and after 1982 Why does the density of the penny change in that direction?
Why does the density of pennies change? Different metals change the mass of a penny because they have different densities. During World War 2, a copper shortage caused pennies to be made mostly of zinc. And finally, the ratio of copper to zinc was changed in 1982, again changing the mass of a penny.