Density and The Thickness of Aluminum Foil
A Unit Designed to Assist High School Science Students to Begin to Develop Basic
Skills in a Laboratory Setting
Revised 7/21/09
Submitted to: Dr. Mike Clough
Prepared by: Larry Price
Including:
A sample of my very traditional density lab, a description of the thickness of
aluminum foil lab, and the narrative of the rational, changes, and activities for the
resulting inquiry unit.
Density Lab:
Density of Irregular Shaped Objects
Equipment:
100 mL graduated cylinder
Platform balance
3 different length bolts
Procedure:
Mass:
Use the platform balances to determine the mass of each of the three bolts as
demonstrated and discussed in class. Record the mass on your lab data table.
Volume:
Use the procedure as demonstrated and discussed in class to determine the volume
of an object by displacement, determine the volume of each of the three bolts.
Review the data table to check the sequence of events.
Clean Up:
Return all materials to the location where you found them. Be sure the bolts have
been dried as much as possible, placing them back in the tray with the sheets of
paper toweling.
Density Calculations:
Use the equations
Density = Mass / volume or D = M/V
to calculate the density of the bolts.
Conclusion:
Determine the average density of the bolts.
Data Table For The Determining The Density of The Bolts
Bolt 1
Mass of the
Bolt
(grams)
Volume of
the Water
and Bolt
(mLs)
Beginning
Volume of
the Water
(mLs)
Volume of
the Bolt
Determined
by
Displacement
(cm3)
Density of
the Bolt
g/cm3
Bolt 2
Bolt 3
Averages
Questions:
1. Explain, in your own words, how you used the process of displacement to
determine the volume of the bolt.
2.
Account for why the individual densities of the bolts differed from bolt to
bolt. What was the “weakest” measurement in your process? Why?
3.
Would averaging the density of the three bolts be a better representation of
the density of the bolts than any single measurement? Why or why not?
Density and The Thickness of Aluminum Foil
Rational, Changes, Time Frame, and Background:
This lab has been developed to assist high school biology student, who have arrive in
my 10th grade biology class, with an opportunity to develop a beginning level of
experience in a laboratory setting. You see, when I began teaching in Clarinda, at
Clarinda High School, one morning I had an occasion to ask my student about a couple
pieces of glassware. No one knew their names or the purpose of the equipment other
then they were intended to “hold stuff, likely liquids”. When I showed them a
graduated cylinder the closest they came was, “it’s a test tube”. With chemistry on the
horizon, and as a former chemistry teacher in Missouri, I decided I had to do
something about this situation. My goals were to: a) familiarize the students with
the basic laboratory glassware, b) reinforce the use of the Metric System of measure,
c) illustrate an indirect measurement, specifically density, and d) finely bring alone
the ability of students to plug numbers into an established equation and solve for
the missing variable. It seemed to me that a density lab would work well to help
students gain this background. They would use glassware to find the volume of an
irregular shaped object by displacement, a platform balance to illustrate the
difference between mass and weight, the density equation to plug in numbers to
find an answer, and the concept of calculated density as an indirect measure. By
adding a second “phase” to the lab in which I ask students calculate the thickness of
aluminum foil using its density I could extend their experience. With as given on the
periodic table and its mass, I could show students how they could find he volume of
the foil from the density equation. Then by using the equation for a rectangular
solid we could find the thickness of the aluminum foil, reinforcing the work we had
just recently completed designed to develop the concepts involving area and volume
measures. Over the years this activity has developed into a unit rather than series
single lesson, in support of laboratory procedure. Aspects of experimental design,
planning a procedure, and developing meaningful data table have become a part of
the unit.
The initial experiences were very much cookbook type labs, frankly I wanted to get
this done so we could begin to do biology. The labs were much like baking a cake, in
which students were told each and every step. All data tables were provided,
sample calculation were included, and even the final calculations where all but set
up on the question sheet so all students had to do little more then plug in the
number and use a calculator. Once completed it became relatively clear students
did become familiar with the glassware, a platform balance, and the density
equation, but little more.
Over the last three school years it has evolved to be more “inquiry” oriented
experience but not a far as I want it to go. So here is what I plan to do, first I still
want the initial part of the lab, that is the measure of density of the bolts (I use sets
of three bolts as the masses) to get us started remaining relatively “cookbook”, with
emphases placed on how to students planning the data table to direct their work in
the lab. Students will be shown the density equation with practice plugging in
numbers to find the density and a demonstration of how to find volume by
displacement, and the use of the graduated cylinders and platform balances.
However, they get more involved in designing the data table. My goal is for the
students to come to understand that a good data table summarizes the steps in the
experiments process and can direct the student’s activities in the lab.
Following the successful completion of the first phase, I would then enter into a
second phase that was once again “cookbook’ like, to apply what was learned to
determine the thickness of a sheet of aluminum foil. What I have been doing in
more recent years is much more “inquiry” like through class discussion. I would like
to see this part conducted in student groups, beginning in groups of two, which may
be allowed to develop into groups of four. The only given in this series of steps will
be the density of aluminum off the periodic table other wise its up to the students to
use their sheet of aluminum foil and the equipment available to find its thickness.
The only requirement is that their final answer must be within 5 of the actually
manufactures claimed thickness of the foil. Note that in order to keep students on
their toes, I’ve used foil from several different sources and thicknesses.
At the conclusion of this unit the class will follow with application of much of the
background material as we dev
Activity 1: Density Lab as described on the attached student handout.
Goal/purpose: To establish a behavior standard and business-like attitude in lab.
To provide students with a hands on activity designed to get the to use various types
of laboratory equipment. The allow student to experience an example of indirect
measurement. To allow students to use a mathematical expression to determine a
required answer. And finally to develop the concept of density. This is a highly
structured lab experience.
Activity 2 Design of a Standard Data Table
Goal/purpose: To establish a uniform standard for a data table. To illustrate the
design of the data table, influences how the data is perceived. And that as well
designed data table can guide a student’s sequence of steps in the lab.
Instructions:
Open your science book and any other second textbook you have with you and
locate five tables.
Look over the table to see what you can find out about how they are “put together”
or arranged.
What is it that “makes the table work”?
How meet with you table partner and together prepare a list of eight to ten patterns
or characteristics they have in common.
Teacher lead class discussion (a guided discussion) describing common
characteristics of good tables:
1. What did you observes about the arrangement of the information in the
table? (Looking for information is arranged in some kind of a logical
pattern.)
2. Why put information (work in the word data) a table? (Looking for
students to decide that a table can summarize and show patterns and
relationships with n information or data.)
3. How is the table arranged? (Looking for columns and rows that are
frequently separated by lines and “boxes”.)
4. How do we know what the rows or columns are designed to show?
(Columns and rows have descriptive titles.)
5. How do we know the purpose of the table (Tables have descriptive titles.)
6. How do we know the meaning of the numbers in the columns or rows?
(The units for the numbers are either given as part of the column or row
title, or the unit is actually written as part of the entry.)
7. Describe some of the ways the data in the table is arranged, what patterns
do you observe? (Looking for big to little, little to big, alphabetically,
chronologically, etc.)
8. Lists prepare our list of common characteristics that make tables work.
(This list should include but not limited to: a) tables have descriptive titles;
b) tables are arranged in columns and rows; c) when ever possible columns
and rows have descriptive titles; d) frequently columns and rows are
separated from one another by lines of boxes, and the table itself is often
enclosed in a box; e) number require units to make them meaningful; f)
units can be displayer with each entry or as part of the column or row
description; g) table have data arranged is a pattern that fits the purpose of
the table; h) table are neat designed to convey patterns of information that
may not otherwise be observable; i) tables are neat and highly organized., j)
other ideas specific to the discussion for that class.
Demonstration:
Using the computer project, we’ll illustrate how to build a data table using Microsoft
word. Microsoft word is selected because all of the computer available at school for
student use has Microsoft word. During the instruction it will be pointed out that
regardless of the format Windows OS or Mac Os Microsoft word works basically the
same and tables prepared on one format can be successfully opened on the other.
Finally for students who do not have Microsoft available at home, we’ll share
information about OpenOffice.org as a source for a compatible free version of
software compatible with Microsoft word.
Hands On Experience:
The culmination of this activity will be for students to prepare a data table from a
set of sample data provided.
Activity 3: Determining the thickness of a Sheet of Aluminum Foil Planning
Goal/purpose:
The primary goal of the activity is to allow students to begin to see how to plan and
design an experiments’ procedure. Also to develop a data table in which they will
record data generated in the experiment/activity. The see first hand how a welldeveloped data table can lead the way in lab. To provide a first time experience
with an inquiry lab. To determine the thickness of aluminum foil within 5% of the
manufactures claimed thickness. To begin to see how separate seemingly isolated
concepts can come together to allow students to solve a seemingly unrelated
problem.
The day before the lab is to be done, students will be show a sheet of aluminum foil
and ask, and in fact be told they will be required to determine the thickness of that
sheet of foil within 5% of its actual thickness. The purpose of the remaining time in
class will be devoted to developing a means of accomplishing the task. Students will
begin their planning in small groups, 2’s the 4’s and then general class discussion.
Once the class has returned together, I will lead a discussion in which they will plan
their approach and develop their data table as a class. Early on they will be remined that it is possible to get the actual density of an element, such as aluminum
from the periodic table. The rest of it will be one their own. Without specifically
giving them a plan I will “guide” them through class discussion, decision making,
and planning to a plan first using the mass of the aluminum foil and the density as
given on the periodic table, to finding the volume of the sheet of aluminum foil.
Having just previously completed a unit on metric measure involving conversion
using length, area and volume of regular objects, they will be lead by their
discussing to recognize that a sheet of aluminum foil is actually three-dimensional.
Using rulers of course the can find the length and width of their rectangular solid,
knowing the volume they can rearrange the equation, H x L x T = Volume to find the
thickness.
Once the plan is in place, the class will develop the data table to be used to gather
the measurements during lab. Allowing the m to discuss and plan the data table will
once again reinforce the experimental design.
Activity 4 Finding the Thickness of a Sheet of Aluminum Foil
Goals and Purposes:
To allow students to experience successful problem solving. To help students
realize they can successful plan and develop a procedure that in fact works, without
being told how to solve the problem. To actually find the thickness of something
much to thin for standard classroom equipment to measure. To reinforce the use of
data tables in lab experiences.
The Plan:
The following class period students will be allowed to conduct their procedure to
determine the thickness of the foil. Several different thickness of foil are available
for which the thickness is actually available online. As many different types of foil
will be employed as possible to insure students have the true experience of finding
an answer to problem is at least seems unique to them. One important requirement
for this final day, no student is allowed to do the lab without having a pre-prepared
data table.
My experience is that almost universally students calculate the thickness well within
the 5% arrange for the foil, and that it only takes about 10 to 15 minutes to do the
procedure and calculation. The remaining time will be devoted to a discussion in
which the class designs the write-for the experiment.
Discussion:
Students will respond to a question/reflection sheet individually and the participate
in a class discussion including questions about technique, equipment selected to
make measurements, the use of standard data tables as a source of information,
calculations, how to improve the process, and the nature of science. Nature of
science questions to include: Is this activity more like science or engineering? How
is this activity like what you think scientists do? Where does creativity enter this
process? In what sets are observations gathered? How is this activity different then
what you think happens in a science lab?”
Note:
In the coming school year, our school is adding several sets of movable classroom
laptops and a complete school wi-fi network. My plan will include the available of
the computer to help with the design of the data tables and to allow students to
complete and submit their writes ups before the end of class, if at all possible.
Attachments:
Attached are the hand out for the density lab, and samples of other materials from
previous years.
Name _________________________________________________ Date ________________ Period _____
Thickness of Aluminum Foil Questions
1. Why do you think we did this activity?
2. What did you learn? What did you learn to do? What can you do with what
your group did?
3. How close to the manufactures predicted thickness of the foil did your
groups data come?
4. How can you account for your high level of accuracy when you are measuring
a thickness too small for you to measure it accurately with your eyes
directly?
5. What was the “weakest” piece of equipment you used?
6. Is this a direct or indirect measure of thickness?
7. How can a good data table guide you through a lab?
8. Is this activity more like what you expect an engineer or a scientist to do?
Why?
9. How do you think the conduct of your group approaches what happens is a
lab? Why?
10. Describe how you and your group used creativity, questioning, planning,
previous knowledge, and equipment to solve this question?
11. What is the periodic table of the elements, and how would it be useful in a
lab?
12. How is this activity different than what you would expect scientists or
engineers to do on a daily bases?