After 1982, the US mint changed the composition of the cent coin to zinc (97.5%) and copper (2.5%). These pennies have a density of 7.185 g/cm3.
What is the actual density of a post 1982 penny?
Because of the change of the composition, copper to zinc ratios, pennies minted before 1982 have a density of 8.8 g/mL and after 1982 are have a density of 7.2 g/mL (4).
Is the density of the pennies in your trial closer to the density of pre 1981 pennies or post 1982 pennies?
The density of pennies made before 1982 was measured to be 8.79 g/mL, while the density of pennies made after 1982 was measured at 6.90 g/mL. This confirms our hypothesis stating that the pre-1982 pennies would be more dense.
How does the density of one penny compare to the density of two pennies?
How does the density of one penny compare with the density of two pennies? Density of 1 penny = 2.6 g / 0.36 cm3 = 7.2 g/cm3 Density of 2 pennies = 5.2 g / 0.72 cm3 = 7.2 g/cm3 The density of one penny is the same as the density of two pennies.
How can you calculate the density of a penny?
Measure the diameter of one penny with a ruler, multiply by 1/2, square the result, multiply by pi to find the surface area, then multiply again by 5 centimeters to get the volume. Next, weigh the stack on an accurate scale. Divide the weight in grams by the volume to get the density.
Why did the density of pennies change?
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.
What is the density of a penny minted in 1980?
Then, in 1982 the Mint introduced a penny that is 97.6 percent zinc and only 2.4 percent copper with a density of 7.2 g/mL. By comparison, the old pre-1982 copper pennies were 95 percent copper and 5 percent zinc with a density of 8.8 g/mL.
What is the volume of a penny?
A new penny has a mass of 2.49 grams and a volume of 0.349 cm3.
Does the number of pennies used make a difference in the value of the density?
As the students increase the number of pennies they use, the relative uncertainty of their calculated density decreases.
What do you expect to observe when a post 1982 penny is placed in hydrochloric acid?
If you take a penny made after 1982 and place it in hydrochloric acid, the zinc core will dissolve, leaving a fragile copper shell. (You just need to file some notches into the penny to allow the acid to reach the core). A penny made in 1982 could go either way, depending on its actual composition.
How do you find the volume of a penny using a graduated cylinder?
Can you measure the volume of just one penny?
Place the penny in the cylinder and let it fall to the bottom. Read the bottom of the meniscus again and record the second volume in milliliters. Care should be taken to read this value.
How do you graph a penny lab?
How do you find the density?
The formula for density is the mass of an object divided by its volume. In equation form, that’s d = m/v , where d is the density, m is the mass and v is the volume of the object. The standard units are kg/m³.
What is the area of a penny?
The Lincoln penny, in its current design since 1909, has a diameter of 19.05 mm (0.75 in) and an area of 0.4420 square inches.
What is the volume of a penny in mL?
Students were able to carefully measure and determine that the volume of a penny was 0.35 mL – most students were very close with a range of 0.33 – 0.37 mL.
What is the mass of 15 pennies?
Thus there are 30 pennies which weigh 2.50 grams, 15 pennies that weigh 3.11 grams, and 5 pennies that weigh 4.67 grams. since each roll contains 50 pennies.
Why are older pennies heavier?
Changing the composite from solid copper to a zinc and copper alloy also changed the weight of the coin itself. Pennies made prior to 1982 are composed completely of copper and are significantly heavier than their zinc and copper alloy counterparts of today.
Why did the density of pennies change in 1982?
In 1982 the composition of pennies was changed because they contained more than 1 cent’s worth of copper. Pennies were being melted down for the value of their metal. Procedure: Place approximately 15-20 mL of water into a graduated cylinder.
Why are pennies before 1982 heavier?
Upon changing the composite from solid copper to the zinc and copper alloy, so to did the weigh of the coins themselves. Prior to 1982, a penny made completely of copper was significantly heavier than the zinc and copper alloy counterparts.
Is a cent a penny?
The penny is the United States’ one-cent coin. The person on the obverse (heads) of the penny is Abraham Lincoln, our 16th president. He’s been on the penny since 1909.
How much is a 1983 D copper penny worth?
If So, Then You Might Have The Rare 1983 Copper Penny Worth $15,000! There’s a rare 1983 copper penny (a 1983-D penny) worth $15,000 — you could find one in your pocket change! Here’s what to look for + Other rare copper pennies.
How do you tell if my 1982 penny is copper or zinc?
How do you find the volume of a coin?
What tool do you use to measure the volume of pennies?
Assuming the coin is a cylinder then you could calculate its volume by measuring its diameter and thickness. A measuring device called a micrometer would provide accurate values for the thickness and diameter of the coin.