Penny "Isotope" Activity
Now that we have reviewed isotopes, why don't we look at the pennies.
Pretend the penny is an atom, and let's see if there are some "isotopes" of
the penny "atom".
Using the two baggies of 20 pennies you receive from the teacher,
complete the table below. BE SURE you make note of which baggies you
have by writing down the symbol (!) on the baggie into your notes AND
DO NOT MIX THE TWO BAGGIES TOGETHER.
Part A:
Copy and complete Table 1 by finding the mass of the penny "atoms"
using one of the four digital balances located around the room. Then
separate each baggie's penny "atoms" into two piles: "Before 1982" (i.e.
Pre-1982) pile and "1982 and After" (i.e. Post-1982) pile.
Table 1
Group
Mass of 20
Penny
"Atoms"
# of Penny
"Atoms" dated
before 1982
Baggie #1
g
Baggie #2
g
# of Penny
"Atoms" dated
1982 to present
Once you have completed Table 1, use Table 1's data to answer and
explain your thinking about the following question in your notes.
Do you think there is a difference in the
masses of the pennies dated before 1982? Why?
Part B:
Copy and complete Table 2 in order to gather some raw data to help you
interpret the data gathered in the Table 1. To begin, for each baggie find
the mass of just the Pre-1982 penny "atoms" and the mass of just the
Post-1982 penny "atoms. Then find the total mass of the Pre-1982 penny
"atoms" and the total mass of the Post-1982 penny "atoms". Lastly, use
the total number of Pre-1982 and Post-1982 penny "atoms" to calculate
the average mass of one penny "atom" from each "isotope."
Table 2
Date Penny
"Atoms"
Minted
Total Mass of Penny
"Atoms"
Average Mass of
One Penny "Atom"
Mass
Total # of Penny "Atoms" in
"Isotope" Group
Pre-1982
g
g
Post-1982
g
g
Penny Isotope Activity Summary
Part C:
In 1982, the United States government changed the way it minted pennies.
Copper was becoming more expensive, so they changed the chemical composition.
Prior to 1982, pennies were made of a material containing 95% copper and 5% tin.
Since 1982, our pennies have a zinc core (98%) with a copper coating (2%). This
is a drastic change and you can see how that change affected the mass of the
penny.
To further prove your thinking about the penny "atom" and its "isotopes", please
use the Periodic Table of Elements and the following directions to calculate the
atomic mass of the pre-1982 pennies and the post-1982 pennies:
·
The pre-1982 penny "atom" is made from 95 "nucleons" of copper and the 5
"nucleons" of tin. Calculate the atomic mass of the copper and tin "nucleons"
in order to find the total atomic mass of the pre-1982 penny "atom."
·
The post-1982 penny "atom" is made of only 2 "nucleons" of copper and 98
"nucleons" of zinc. Calculate the total atomic mass of the post-1982 penny
"atom."
Assessment:
To conclude this activity, you will need to write a summary. This summary should
be write in paragraph format, which means in COMPLETE SENTENCES. Also,
since this is a summary of the activity you have already completed, this should be
written in the first person and the past tense. The items with the
are what
should be in the summary paragraph and will be scored.
Using data from both tables:
>
Explain why the two groups of pennies from Table 1 had different masses,
using the data from Table 1 as evidence to prove your claim.
>
The penny "atom" has "isotopes". Use the data from Table 2 as evidence to
this claim. Explain the number of "isotopes" of the penny "atom" you
found while doing this activity (i.e. how many versions of the penny "atom"
are there?).
DON'T FORGET TO USE THE DATA FROM BOTH TABLES
TO PROVE WHAT YOU ARE CLAIMING.
>
Compare the two atomic masses you just calculated in Part C. Use the
calculations to explain how these mass differences relate to the concept of
atomic isotopes.