Open-Ended Project
Choosing A Cell-phone Plan
Lesson
Pre-requisite Knowledge:
Students should understand linear equations and interpreting
their graphs. Students should be familiar with graphing calculators, navigating
the internet, and be proficient in Excel. (This lesson is most appropriate for
Algebra I Advanced students or Algebra II students.)
Objectives:
In this project:
-
students will record in a log the number of minutes they
talk on the phone everyday for one week and use these numbers to estimate
the number of minutes they spend on the phone each month.
-
students will explore the internet for at least three
cell phone plans in the Athens, Georgia area and evaluate the various plans
in order to make a decision as to which plan best suits their individual
needs if they were to choose to buy a cell phone. (Plans should be for local
calling only; assume they do not make long-distance calls.)
-
students will use Excel to record the class data (number
of minutes on the phone per month).
-
students will graph their three plans on a graph using
Excel and graphing calculator and interpret their graphs.
-
students will present their findings to the class on a
medium of their choice.
Materials:
-
access to the internet: Netscape or Internet Explorer
and printer
-
access to Excel and printer
-
access to TI-83 Graphing Calculators
-
teacher-made handouts: "Choosing a Phone
Plan: Phone Log" and "Choosing A Phone
Plan: Summary"
Click here to see the handouts:
Task:
Time frame: (two weeks)
In the first week, continue regular class sessions (hopefully
on linear equations and graphing), but give the students the handout "Choosing
a Phone Plan: Phone Log" and ask the students to record daily the number
of minutes they talk on the phone. Have students do this for seven consecutive
days. (Check their log daily to make sure they have not forgotten!)
In the second week, begin the "open-ended" project.
Day 1: Ask the students to work in groups of four(teacher
should assign these) and use the internet to find three cell phone plans offered
in the Athens, Georgia area. (Adapt this to your area.) They should print their
results and have them approved as appropriate options by the teacher.
Day 2: Ask the students to write cost equations for the cell
phone plans they have chosen. (For example, a plan that calls for a rate of
13.50 per month plus ten cents per minute would yield the linear equation y=13.50+.10x)
If students have not previously written equations from given parameters, the
teacher may have to provide extra guidance. They should then find the cost of
each of the three plans for each member of their group by plugging in their
estimated number of minutes per month from their Phone Logs.
Day 3: Ask the students to develop a worksheet in Excel that
records the number of minutes each team member talks on the phone per month
in column 1. (This is estimated using their 'Phone Log'.) They should then insert
their formula for estimating the cost of their cell phone plan #1 in column
2, cell phone plan #2 in column 3, etc. and use these to find the cost of each
plan for each class member. (The teacher will need to have students record data
in alphabetical order, so they will later be able to reconnect their findings
with the team member.) Students should see if their results match their hand
calculations from Day 2.
Day 4: Students will again use their worksheet in Excel; each
member will graph the three cost equations that their personal data was plugged
into. (Each member should have one graph with three lines that reflects their
personal data. Each member's graph should be different.) Ask students to print
their graph and then use a graphing calculator to see if their graphs correspond.
The students should then individually complete the handout "Choosing a
Phone Plan: Summary."
Day 5: Students will present their findings to the class as
a group stating which plan works best for each member.(Most likely, the same
plan will not be the 'best' plan for each member of the group. The presentation
should include their graphs, summaries, and explanations.
Evaluation:
Students' grade is determined by the following five point
rubric:
group participation (1 point)
presentation: includes graph, summary, and explanations (2
points)
graphs: accurate depiction of their data (2 points)
The students "Summary" sheet
is graded as any other homework assignment (on a 100 point scale). This should
be graded on whether they chose the appropriate plan and their explanations/justifications
for their choice.
To see a summary of my students' grades and to read my evaluation
of the project in general, click here.
Follow-up:
I followed up this project by presenting 'my
choice' and asking students questions relating the graphs to my decision, and
to linear equations in general. I wanted my students to see the connections
between the subject and the 'real world'
.