# Density-of-South-African-Coins

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```					Zakhele Primary School Lesson Plan
Comprehensive Science 6th and 7th Grade
Teachers: Mr. Sherwin Jose (Miami teacher), Ms. Kat Loftus (Miami fellow), Mrs. Sonto
Mntambo (Pretoria teacher) and Mrs. Busi Hoseka (Pretoria teacher)
NATIONAL STANDARDS:

NS.5-8.2 Physical Science

OBJECTIVE: What will your students will be able to do by the end of class?

Students will complete two density labs: 1) South African Coin Density Lab and 2) Dunkin’ for
Density. Through exploration, students will have a thorough understanding of density, density
calculations, measuring mass, measuring displaced volume, and the equation D = m/v.

ASSESSMENT: How will you know                    KEY POINTS. What three to five main ideas
Defining Success

concretely that all of your students have        or steps will you emphasize in your lesson?
mastered the objective?

Students will complete the lab worksheet.        1. Density is mass per unit volume of a
Next class, students will design an experiment   material, substance, or solution.
to answer the question “What factors affect      2. Mass is the amount of matter in an object.
the density of gum?”                             3. Weight is the gravitational pull on an
object.
4. Volume is the amount of three-dimensional
space an object occupies
INVITATION: How will you focus, prepare and engage students            MATERIALS:
for the lesson’s objective? What questions will students answer?
What observations will be made?

Teacher will ask the classroom to                                      Coin Density Lab:

1. List as many similarities as they can about the two cans of coke.   1. 13 One Cent coins

2. List as many differences as they can about the two cans of coke.    2. 13 Ten Cent coins
Two students will be taking notes on the board, one for regular
coke and the other student for diet coke. The teacher will then        3. triple beam balance
place the regular coke in the tank of water, and then the diet coke.   4. one 50mL or 100mL
Ask the students write down their observations and hypothesize as      graduated cylinder
to why one can of coke is floating.

Dunkin’ for Density

1. 3 small pepper shakers
with lids (seal holes with
Learning Cycle

crazy glue to keep water
from entering)

2. marbles

3. paper clips

4. coins
EXPLORATION: How will students engage in open-ended
5. aquarium or large
exploration of real phenomena, discussion about their discoveries,
beakers
ideas, and questions that arise?
Students will discuss their observations and hypothesis. After the
cylinder
student-centered discussion, teacher will explain the why the diet
coke can floats. Coke has 39g or sugar. Teacher will show the          7. triple beam balance
students what 39g of sugar looks like. Show the sugar in a beaker
so students can see how much space it takes up when compared to
the can. Then, show the students 125mg of Nutra Sweet. Show the
Demonstration:
125mg of Nutra Sweet on an idex card so students can see the small
amount of Aspartame needed in Diet Coke to make it sweet. This         1. 12 oz can of Coke
will introduce the concept of density. The regular coke has more
sugar (thus a greater mass) crammed into the same amount of space      2. 12 oz can of Diet
(volume) as the diet coke can; therefore has a greater density         Coke
causing it to sink. After introducing the concept of density, weigh
the Coke and Diet Coke to determine the mass of each can.              3. aquarium
Students will learn to find the volume of each can using water
displacement.                                                           4. sugar

CONCEPT INTRODUCTION: How will you convey the                           5. nutra sweet
knowledge and/or skills of the lesson? What will your students do
to process this information?

After the demonstration, the classroom will be divided in teams of
four. All members of the teams will be assigned a role (i.e. project
director, materials manager, technical manager, safety director.)
The materials manager will pick up the materials for their group.
Half of the class will work on the “South African Coin Density
Lab” and the other half will work on the “Density Lab.” After 30
minutes, the groups will switch labs. The teacher will walk around
the room as a resource person who answers questions, asks
questions, provides encouragement.

APPLICATION: In what ways will your different learners attempt
the objective on their own? How will students apply the new
knowledge and skills to solving a problem or meeting a challenge?

Each group will present to the class the results of the exploration
activities. These results will lead to a student-centered discussion
about density. As students are sharing their results, teachers should
ask them questions about the lab to test their knowledge.

REFLECTION: How will you have students summarize what
they’ve learned and how they arrived at their current
understanding? How will you reinforce the objective’s importance
and its link to past and future learning as well as new conceptual
frameworks?

After the student-centered discussion, the teacher will further
explain density, density calculations, measuring mass, measuring
displaced volume, and the equation D = m/v. Teacher will explain
how the triangle below will help them remember the equation for
density. The teacher can give the example of Gold vs. Real Gold.

EXTENSION: How will you incorporate ideas for further exploration?
Next day: The classroom will be divided in teams of four. All members of the teams will be assigned a
role (i.e. project director, materials manager, technical manager, safety director.) The materials manager
will pick up the materials for their group (sugarless gum, bubble gum, different brands of gum, triple
beam balance, water, and graduate cylinder.) The class is then asked a question: “What factors affect
the density of gum?” No further detailed instruction is given and each group on their own will develop
an experiment to answer the question. The teacher will walk around the room as a resource person who
answers questions, asks questions, provides encouragement, and provides other equipment if it is
requested. Teacher will approve the experiment design first.

DIFFERENTIATION: How will you differentiate your instruction to reach the diversity of learners in
your classroom (ELL STRATEGIES/IEP IMPLEMENTATION)?

Groups will have a mixture of low level learners with high level learners.
South African Coin Density Lab

(Penny lab modified)

Procedures:

1. Measure the mass of a One Cent coin and then of 2, 3, 5, 7, 9, and 13 One Cent coins. Record
all the mass measurements for One Cent Set A.

2. Repeat the procedure using a Ten Cent coin. Record all the mass measurements for Ten Cent
Set B.

3. Using a 50mL or 100mL graduated cylinder, measure the volume of a One Cent coin from Set
A. Then, find the volume of 2, 3, 5, 7, 9, and 13 One Cent coins. Record all the volume
measurements for One Cent Set A.

4. Repeat procedure for Ten Cent Set B. Record all the volume measurements for Ten Cent Set
B.

Purpose Statement: What is the purpose of this lab?

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Pre-Lab Questions:

1. Explain density in your own words.

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2. How is the One Cent coin different from the Ten Cent coin?

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3. a) What instrument will you use to measure the mass of the coins? _______________

b) How will you determine the volume of the coins?
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4. It is important for the coins to be dry before the mass or volume is determined.
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5. Why can the slope of a line be used to determine the density of the coin sets?

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Hypothesis

Write a hypothesis based on the purpose of the lab. Include an explanation for your prediction.

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Data Table--Fill in the # of coins you will use and the measurements you will make for each set.

Set A (One Cent)                 Set B (Ten Cent)

# of Coins         Mass (g)       Volume (mL)        Mass (g)        Volume (mL)

1

2

3

4

5

6

7

8

9

10

11

12

13

Data Analysis/Conclusion:

1. Using graph paper, create a graph of your data (mass vs. volume). You will have two lines on
your graph (A—One Cent and B—Ten Cent). Distinguish between the two sets of data on your
graph. Your graph should have:

a.) correct data intervals

b.) descriptive title

c.) labeled axes with units

d.) best-fit lines

e.) key or method to distinguish both lines
2. a. Pick two points on each best-fit line (one towards the bottom and one towards the top).
Label all four points with their correct (x, y) values.

b. Calculate the slope of each line and include units. Show your work below.

Set A (One Cent)                                Set B (Ten Cent)

c. What is the density of the A (One Cent) coins? _________

d. What is the density of the B (Ten Cent) coins? _________

3. a. Which set of coins (One Cent or Ten Cent) is denser?

b. Restate your hypothesis (just the prediction part).

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c. Was your hypothesis supported or rejected by the data? ________________________

d. Based on what you know about the density, explain the difference in the density of the two
sets of coins.

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4. How would the density of 10 One Cent coins compare to the density of 10 Ten Cent coins?
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5. In 1989 the South African Mint Company proposed a new coin series for South Africa and
recommended a complete change to electroplated* coins as a solution to the increasing risk of
fake coins. If you had a Ten Cent coin and the design was unreadable, how would you determine
if it is real?

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*Electroplating is a plating process that uses electrical current to reduce cations of a desired material from a
solution and coat a conductive object with a thin layer of the material, such as a metal.

6. Think of another example in the world where determining the density of a substance would be
useful in identification. Describe the situation and why density would be important in the
identification.

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Dunkin’ for Density
Materials:

1. 3 small pepper shakers (seal holes with crazy glue to keep water from entering) or small plastic
canister with lid. The opening of the shaker or canister must be wide enough to fit marbles, paper clips,
etc.)

2. marbles

3. paper clips

4. coins

5. aquarium or large beakers

6. large graduated cylinder

7. triple beam balance

OR

Procedure Part 1:
1. Using the materials at your desk, modify three canisters so that they will float, sink, or remain
suspended in the middle of a tub of tap water.
2. One canister should float (1)
3. Another should remain suspended (2)
4. And another should sink to the bottom (3)
5. Have your teacher check your canisters before you proceed to the next part.

Purpose Statement: What is the purpose of this lab?

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Procedure Part 2:
1. Once you have completed Part 1, use the equipment provided to find the mass and volume of each
of the three canisters.
2. Record the information in Table 1.
3. Calculate the density for each canister using the formula D=M/V
Data:
Table 1: Mass, Volume and Density of canisters
Canister                  Mass (g)               Volume (cm3)             Density (g/cm3)
1
2
3

Data Analysis/ Conclusion

1. What is the mass of an empty canister? __________________________________

2. What caused each canister to stay at their level in the water? Explain what caused the canisters to float,
sink, or suspend using the term density.
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Conclusion: 2-3 sentences on what you learned.

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Experimental Design Diagram

Title:

Problem
Statement:

Hypothesis:

Independent
Variable:

Dependent
Variable:

Control Test:

Variables        1.

held constant:

2.

3.

Materials
(list):

Procedures:

Results:

Conclusion:

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