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Cockroach Slope

Cube Fellow: Casey Gregory

Teacher Mentor:
Pamela Callahan

10th /Honors Geometry

KY Standards:

MA-HS-5.1.5 Students will determine the slope and intercepts of a
linear function.
MA-HS-4.1.2 Students will construct data displays for data with no
more than two variables.
Kentucky Academic Expectation 1.6: Students use computers and other
types of technology to collect organize and communicate information and

• The student will exercise their ability to quickly compute the slope
and y-intercept of a line.
• The student will visually be able to determine the difference between
a line with negative, positive, zero or undefined slope.
• The student will understand that when the y-intercept is zero, the
equation of a line is of the form y=mx where m is the slope.
• The student will understand that when the slope is zero, the equation
of the line is of the form y=b where b is the y-int.
• The student will demonstrate their capability of using a Java applet
via Internet Explorer.

Resources/Materials needed:
• One computer per student with internet access
• Data Collection Sheet (attached)

Game Summary:
The purpose of this game is to watch a cockroach crawling along a
line. The student should enter the slope (and/or y-intercept) as prompted,
then click Fire!. If they have entered the required information correctly, the
cockroach will be exterminated.

This is an excellent activity to give students practice with finding slope as it
breaks down the levels in logical steps. First the students compute only the
y-intercept. During the second level students compute only the slope. Then
each level gets successively harder: lines with positive slope, lines with
positive fractional slopes, lines with negative slopes, lines with negative
fractional slopes, all mixed together.

Mrs. Callahan was having a hard time getting students interested in
slope. They had used slope in their previous math classes, and had not
mastered the concept. Many students were confused and discouraged about
learning (re-learning) the concept.

Mrs. Callahan asked me to come up with a fun, interactive way to get
students interested in slope. I found this Java applet on the web and
formulated an activity sheet to go along with it. I was interested, not only in
making sure that the students played the game, but also in seeing how long it
took them to compute each level. (That is why there is a space to record
how many cockroaches were exterminated.)

Prior Knowledge
Students are expected to have a solid understanding of what slopes, y-intercepts,
equations in slope intercept form are and how to compute them.
The students we were working with had just finished a two-day lesson on the
above information and were ready to practice. This is not a lesson to use
before a student has been given the appropriate definitions and formulas as
the game does not explain in depth how to determine slope or y-intercept.
The game does give good hints, but they would be of little use for a student
who did not have the background information.

Outline of Lesson
I. This activity is to be done individually. I believe that group-work
would be quite disruptive, especially if the class is large.

II. Before going to the computer lab (perhaps even the class before)
the teacher should go through and explain the cockroach activity.
It would be best if the teacher could actually demonstrate how the
game is played. The instructions should be explained in advance
so that students know exactly what is expected of them. The
activity should take at least 50 minutes.

III. On the day of the activity the students should be taken straight to
the computer.

IV. During the activity the teacher should circulate making sure that
the students are on task and not having any trouble doing what the
sheet asks of them.

V. The wrap-up is the most important part of the activity:

a. The teacher should go over the results with the student that day
if possible. The teacher should review the data sheets if there is
not time and then review the activity the following day.

b. The teacher should ask such questions as:
i. “What happens when the slope is zero?” (What does the

equation look like/what does the graph look like)
ii. “What happens when the y-intercept is zero?” (Does the
line go through the origin?/What does the equation look

iii. “What is the slope of a horizontal/vertical line?”
iv. etc...

c. The teacher should give students a chance to share something
that they learned.

*Mrs. Callahan actually spent the day after the activity in class going
through the game where she projected it onto the screen in her classroom.
The students struggled with it in the computer lab, and she went through
several of the levels herself in front of the class discussing her thought

*Note: I highly suggest you try this activity before giving it to your
students. It takes a short time to get used to, and will make the classroom
activity go much more smoothly. If you have the capability to project the
computer screen to the class, it would be very helpful to walk them through
the first level and explain your thought process.*

**Something to think about: Many of the students were discouraged at first
with this activity because the cockroaches move fairly fast up and down the
line. They were worried that if they did not compute the slope fast enough
that they would lose a level. The game allows nearly 20 cockroaches to
accumulate on the line before abandoning the level. Even then, the student
will be able to play the level over. Just assure your students that they have
plenty of time to compute each step. The hints are often very helpful, as
they highlight the key coordinates on the axis.***

-Suggestion for follow up:
Several bell-ringers could be created for follow up on this activity. One idea
I would like to see is on an exam or quiz, a screen-shot of the game when
there are 10-12 cockroaches on the line (so that the line can be seen in a still
frame). The teacher could simply ask the equation of the line so that the
activity is not forgotten about later, and the students can have a little sense of
enjoyment while taking the exam/quiz. (Teachers could even come up with
some other object to put on the line, such as pencils, etc.)

Lesson Source

I developed this activity and the data collection sheet based on the Java
applet at:

Mode of Instruction
This activity should follow a unit on slope. This is a good
supplemental activity before an exam. The mode of instruction is student
self-discovery on an individual basis. Each student is responsible for their
own work and learning. The teacher is only a facilitator and wrap-up leader.

Date of Implementation/ Estimated Time

Tuesday, December 2, 2008/ 50 minutes

Date Submitted to Algebra3

Tuesday, February 17, 2009

attachment: Cockroach Data Collection