Answer: The pennies minted before 1982 are denser than the pennies minted after 1982. Pennies minted prior to 1982 should have a density almost the same as pure copper (8.96 g/cm 3) while pennies minted after 1982 should have a density almost the same as pure zinc (7.14 g/cm 3). What is the average density of a penny before 1982?
What is the density of pennies?
Pennies minted prior to 1982 should have a density almost the same as pure copper (8.96 g/cm 3) while pennies minted after 1982 should have a density almost the same as pure zinc (7.14 g/cm 3).
When did the composition of the penny change?
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. Fig. 7: Magnified view of a Lincoln head penny, showing the relief.
How do you find the average mass of multiple pennies?
Find the average mass of multiple pennies from the same year. After weighing it find the volume by placing the pennies into a 50 ml beaker with 15 ml of water. Note the change in volume to obtain the volume of the pennies, obtain the average volume, and then calculate the density by dividing the mass of the penny by the volume.
How do you find the volume of a penny?
Note the change in volume to obtain the volume of the pennies, obtain the average volume, and then calculate the density by dividing the mass of the penny by the volume. 2.) To keep measurements accurate and precise test multiple pennies from the same year and make sure to measure 10mls of water as precisely as possible.
What does it mean when a micrometer is narrow?
What is the best tool to measure the thickness of a penny?
What is the average thickness of 100 pennies?
Why does RMS underestimate the true error?
How much do pennies weigh?
How thick is a penny?
What is the measurement uncertainty of a penny?
See 2 more
What is the density of a penny made before 1982?
From 1962 until 1981, the US cent coin was made of copper (95%) and zinc (5%). These pennies have a density of 8.85 g/cm3. 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.
Why do you think that pennies made before 1982 have a different density than pennies made after 1982?
The new penny looked identical to the previous coins but it was cheaper to produce. While the new penny was the exact same size as the old one, it weighed less because zinc is slightly less dense than copper. The change from copper to zinc took place in 1982.
How can you use density to determine whether a penny was minted before 1982?
Pennies minted prior to 1982 should have a density almost the same as pure copper (8.96 g/cm3) while pennies minted after 1982 should have a density almost the same as pure zinc (7.14 g/cm3).
What is the density of an old penny?
8.8 g/mLMint produced more than 130 billion pennies. 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.
Why is a 1982 penny worth $10000?
So for the past 30 years, pennies have been made with an alloy comprised of 97.5% zinc and 2.5% copper, but pennies minted before 1982 are 95% copper and 5% zinc. The price of copper has more than quadrupled over the past 10 years.
What is the difference between pre and post 1982 pennies?
Pre-1982 pennies contain a much greater percentage of copper. Post-1982 pennies are mostly zinc.
How much should a 1982 D small date penny weigh?
about 3.1 gramsThere are two key diagnostics: the size of the date and the coin's weight. The 1982-D small date bronze weighs about 3.1 grams, versus only 2.5 grams for the far more common zinc issue.
Are older pennies more dense?
The density depends on when the penny was made. Fairly new pennies have a density of 7.15 grams per cubic centimeter (g/cc), though very old ones can be as high as 9.0 g/cc.
How can you tell the difference between a small date and a large date 1982 penny?
0:527:161982 PENNY SMALL DATE VS LARGE DATE - YouTubeYouTubeStart of suggested clipEnd of suggested clipNow also on the eight you can see that there's much more space in the bottom of the 8 on the smallMoreNow also on the eight you can see that there's much more space in the bottom of the 8 on the small date as opposed to on the large date.
Are pre 1982 pennies denser?
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).
How much should a 1971 D penny weigh?
3.11 gramsA typical 1971-D Cent should weigh 3.11 grams.
Which coin has the most density?
CounterfeitsGold is denser than almost all other metals, hence hard to fake. ... The weight and dimensions of a coin of .More items...
Why do pennies before 1982 have a different mass than newer pennies?
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.
Why are pennies different after 1982?
In 1982, the fast-rising price of copper forced the U.S. Mint to change the composition of the penny to primarily zinc, with pure copper plating. This change allowed the “copper” penny to retain its traditional appearance.
Why do older pennies have a greater density?
A post-1982 penny has a mass of 2.5 grams, while the pre- 1982 pennies have a mass of 3.1 grams. 1982 pennies may have either mass. Since all pen- nies have an identical volume, a greater mass indicates a greater density. Copper is denser than zinc.
How can you tell the difference between 1982 pennies?
For pennies dated 1982, when both copper and zinc cents were made, and best way to determine their composition is to weigh them. Solid copper pennies weigh 3.11 grams (+/- 0.130 g.), whereas the copper plated zinc pennies weigh only 2.5 grams (+/- 0.100 g.).
How to calculate the density of a penny - Quora
Answer (1 of 7): Usually, the best way to measure density is through Archimedes' principle (Archimedes' principle - Wikipedia), but since a penny weighs only about 2.5 g, you would have to use a centigrade balance to get a reasonably accurate measure using a single penny. Secure your penny to a h...
Measuring The Density Of Pennies, Sample of Essays - EduCheer!
1. The equation that relates density, mass, and volume is: density = mass / volume. 2. All substances have unique densities, so if you are able to find the density of a substance, you can properly identify it.
Penny Density Lab Report - Elizabeth Halbrooks 6th Period...
Elizabeth Halbrooks 6th Period Chemistry September 1, 2017 Penny Density Lab Introduction It is a commonly known fact that after 1982 pennies were manufactured with less copper. Pennies made before 1982 contained 95% copper and 5% zinc; the rising cost of materials has increased the production cost over the value for pennies. The pennies made after 1982 contain 97.5% zinc and only 2.5% copper ...
Density of Pre-1982 and Post-1983 Pennies.pdf - Course Hero
Purpose and Theory The objective of this lab was to find the density of pennies before 1982 and after 1983 and to compare. Pennies’ composition was changed in 1982. Before, the penny was 95% copper and 5% zinc. Now, the penny is 97.5% zinc and 2.5% copper. Density is the degree of compactness of a substance. Density’s formula is: Density = mass/ volume.
Density Calculator
Note that density is also affected by pressure and temperature. In the case of solids and liquids, the change in density is typically low. However, when regarding gases, density is largely affected by temperature and pressure.
What does it mean when a micrometer is narrow?
For example, if a micrometer can be read to high precision, but the micrometer itself is manufactured so that all the measurements taken with it are a little bit low, the distribution of measurements may be narrow, indicating small statistical errors, but the whole distribution may be shifted from the "true" value, indicating some sort of systematic error. In figure 4, the RMS of the thickness measurements is 0.07mm, indicating a fairly small statistical uncertainty, but the center of the distribution is too low (at 1.42mm instead of 1.52mm where it belongs) indicating some kind of systematic error in the measurement process. (In this case, the two faces of the micrometer are not exactly parallel; on one side the micrometer, where we made all the measurements, it measures a little too low and on the other side it measures too high.)
What is the best tool to measure the thickness of a penny?
Clearly, a ruler is not the best tool for trying to measure the thickness of a penny. It's not precise enough. A better tool might be a Vernier caliper (figure 2) or a micrometer (figure 3). These devices can easily measure to a precision of 0.05 mm or better.
What is the average thickness of 100 pennies?
Fig. 4: A sample of 100 thickness measurements of new pennies using a crude micrometer. The average thickness for this sample is 1.42mm and the RMS of the distribution is 0.07mm.
Why does RMS underestimate the true error?
Note for geeks: For small data samples, the sample RMS tends to underestimate the true error because the mean of a small sample has smaller deviations from its component measurements than the true value. In the extreme case, a sample of one measurement gives a deviation of zero - the mean is the same as the single measurement - which obviously underestimates the typical deviation from the true value. For sample sizes of 6 measurements or more, the effect is usually smaller than 5%.
How much do pennies weigh?
First of all, attentive students may notice that the mass measurements for pennies tend to cluster around two separate values. Some pennies weigh in around 2.5 grams, while others are closer to 3.1 grams (figure 5). There aren't many measurements in between. The reason for this odd behavior is that in 1982 the U.S. penny composition changed from 95% copper and 5% zinc to 97.5% zinc and 2.5% copper. 3 Figure 6 shows a scatterplot of mass versus year, demonstrating the change. Since we're trying to measure the density of pennies, it's important to pay attention to the year the pennies were minted, and to keep these two populations separate. Pennies minted prior to 1982 should have a density almost the same as pure copper (8.96 g/cm 3) while pennies minted after 1982 should have a density almost the same as pure zinc (7.14 g/cm 3 ). If we assumed we were trying to measure the density of pure copper pennies, then including pennies minted after 1982 in the measurements would amount to a systematic error.
How thick is a penny?
The diameter and thickness can be measured with a ruler to a precision of about half a millimeter, maybe a little better. The diameter of a penny is nominally 19.05mm and the thickness is nominally 1.52mm at the rim. 1.
What is the measurement uncertainty of a penny?
The reason is that the measurement uncertainty (about half a millimeter using a ruler) is a large fraction of the thickness of the penny. It amounts to about 30% uncertainty (0.5mm/1.5mm ≈ 30%) and will produce about a 30% uncertainty in the density.
What was the mass of a penny in 1982?
On the graph Mass vs. Year-Old and New Pennies (Mass of pennies from 5 decades), we saw that pennies minted before 1982 had a mass around 3.0 – 3.1 grams and those minted after 1982 had masses around 2.4 to 2.5 grams. However, there were slight differences in the masses within the two major “minted year” groups we saw. The team had to calculate the sample volume (V), the sample density (D) and the average volume of a penny. We also had to do the same for the zinc and copper samples in Data Table PRE and POST. Results/ Conclusion: PRE, (old) has higher density compare to (POST, new) PRE is made all of 95% Copper. POST is made of 95% Zinc (Copper density 8.96 g/mL. Zinc density 7.14 g/mL.). After examining the Mass vs. Mint Year graph, my partner and I hypothesized that the drop in the mass after the year 1982 signified either a
What was the composition of pennies before 1982?
CHEM 101A Penny Lab Report Abstract: Before the year 1982, pennies were made up of a majority of Cu. However, after that year, the composition of pennies changed to a majority of Zn. Our graph of the masses of 12 pennies and the year they were minted in showed a trend in the masses of pennies before the year 1982 and after 1982. In order to find out what caused this change, we used the density of the pennies. Density is an intensive property of a system which means it is “a physical property of the system that does not depend on the system size or the amount of material in the system.” The team took the laboratory further and found the masses and volumes of groups of pennies separated by whether they were minted before or after 1962. By graphing the mass vs. volume of these samples, and finding the densities of each sample, we found that it was a change in penny composition which supports the fact that after 1982, pennies were made with a zinc core and copper coat instead of mostly copper. Also, we proved the changed in composition by putting a nicked old penny and a nicked new penny both into a solution of HCl (hydrochloric acid) and the new penny was the only one to react. Introduction: Pennies minted before 1982 were made up of a mixture of 95% copper and around 5% zinc. In other hand, after a while, making pennies with such a high content of copper became too expensive. Instead, pennies after the year 1982 were minted with a zinc core and a copper coating, around 97.5% zinc and 2.5% copper. The differences in the penny’s compositions changed many of their characteristics. Changing the composition of an object and keeping the volumes constant means some properties of the object such as the mass, density and some chemical properties of the object must
What is the composition of pennies?
composition of pennies. The history our results back up is that in 1982 zinc replaced copper as the major component in pennies.
Why did the density of the penny drop in 1982?
2.) Based on the data provided by the laboratory section, the density of the penny remained unchanged until 1982 when the overall average density dropped due to the composition of the penny changing. As clearly seen above there was a lot of human error or possibly calculation error. The year 1991 should be disregarded and years with 0 densities were due to not having that penny year tested.
How to find the density of a penny?
After weighing it find the volume by placing the pennies into a 50 ml beaker with 15 ml of water. Note the change in volume to obtain the volume of the pennies, obtain the average volume, and then calculate the density by dividing the mass of the penny by the volume.
What metal replaced copper?
Based off of the density calculation for the years 1995-1999 it is clear that the unknown metal that replaced most of the copper is zinc with a density of 7.14 g/ml. Human error is mostly to blame for the years 75-79 calculation.
What does it mean when a micrometer is narrow?
For example, if a micrometer can be read to high precision, but the micrometer itself is manufactured so that all the measurements taken with it are a little bit low, the distribution of measurements may be narrow, indicating small statistical errors, but the whole distribution may be shifted from the "true" value, indicating some sort of systematic error. In figure 4, the RMS of the thickness measurements is 0.07mm, indicating a fairly small statistical uncertainty, but the center of the distribution is too low (at 1.42mm instead of 1.52mm where it belongs) indicating some kind of systematic error in the measurement process. (In this case, the two faces of the micrometer are not exactly parallel; on one side the micrometer, where we made all the measurements, it measures a little too low and on the other side it measures too high.)
What is the best tool to measure the thickness of a penny?
Clearly, a ruler is not the best tool for trying to measure the thickness of a penny. It's not precise enough. A better tool might be a Vernier caliper (figure 2) or a micrometer (figure 3). These devices can easily measure to a precision of 0.05 mm or better.
What is the average thickness of 100 pennies?
Fig. 4: A sample of 100 thickness measurements of new pennies using a crude micrometer. The average thickness for this sample is 1.42mm and the RMS of the distribution is 0.07mm.
Why does RMS underestimate the true error?
Note for geeks: For small data samples, the sample RMS tends to underestimate the true error because the mean of a small sample has smaller deviations from its component measurements than the true value. In the extreme case, a sample of one measurement gives a deviation of zero - the mean is the same as the single measurement - which obviously underestimates the typical deviation from the true value. For sample sizes of 6 measurements or more, the effect is usually smaller than 5%.
How much do pennies weigh?
First of all, attentive students may notice that the mass measurements for pennies tend to cluster around two separate values. Some pennies weigh in around 2.5 grams, while others are closer to 3.1 grams (figure 5). There aren't many measurements in between. The reason for this odd behavior is that in 1982 the U.S. penny composition changed from 95% copper and 5% zinc to 97.5% zinc and 2.5% copper. 3 Figure 6 shows a scatterplot of mass versus year, demonstrating the change. Since we're trying to measure the density of pennies, it's important to pay attention to the year the pennies were minted, and to keep these two populations separate. Pennies minted prior to 1982 should have a density almost the same as pure copper (8.96 g/cm 3) while pennies minted after 1982 should have a density almost the same as pure zinc (7.14 g/cm 3 ). If we assumed we were trying to measure the density of pure copper pennies, then including pennies minted after 1982 in the measurements would amount to a systematic error.
How thick is a penny?
The diameter and thickness can be measured with a ruler to a precision of about half a millimeter, maybe a little better. The diameter of a penny is nominally 19.05mm and the thickness is nominally 1.52mm at the rim. 1.
What is the measurement uncertainty of a penny?
The reason is that the measurement uncertainty (about half a millimeter using a ruler) is a large fraction of the thickness of the penny. It amounts to about 30% uncertainty (0.5mm/1.5mm ≈ 30%) and will produce about a 30% uncertainty in the density.