Lesson Write-Up For Fall Quarter 2011
Your name: Herrick Chang, Jeff Cantle
Title of Lesson: Zombie Research Training – Heart Rate Monitors and their uses.
Grade Level: 10th-12th
Subject(s): Biology, Physiology
Summary:
Day 1:
Students will learn how to build a simple heart rate monitor. In the process, they will learn
about basic information on electricity and LEDs. They will also learn how infrared is a light
in which cannot be detected by the naked eye but can be seen by other sensors such as
cameras or photodiodes. From there, the will understand how these concepts help make a
heart rate monitor work.
Day 2:
Students will use the heart rate (HR) monitors to take a baseline HR recording. Students
will then be asked to predict what the HR response will be to a stimulus (i.e. exercise,
caffeine) before performing the measurements themselves, using the heart rate monitors
that they built.
Time Required:
2 x 50 minute periods, possibly some wrap-up time (10 minutes or so) on a third day
Group Size:
Up to 6 groups of students, with 4-6 students / group
Cost to implement:
Not provided
Learning Goals:
1) For students to understand how a heart-rate-monitor works.
a. Review of electromagnetic spectrum (infrared light).
b. Learning about reflections of oxyhemoglobin with respect to infrared light.
c. Learn what a photodetector is.
2) Understand the relationship between normal heart rate and HR response stimuli
such as exercise, autonomic nervous system tone, etc.
Level of Inquiry:
Guided inquiry. Students will be given a task to follow to create the HR monitors, and given
experiments to monitor HR during.
Introduction / Motivation:
Day 1:
Assuming a storyline of a zombie apocalypse, students are the recruits for the Zombie
Research Division. In order to survive the apocalypse, they must learn to how to assemble a
heart rate monitor to determine who are zombies or humans. Students will work in groups
and race to assemble a heart rate monitor. The assembly of the heart rate monitor will have
certain checkpoints set up and must be checked off before receiving more parts and
continuing their build.
Day 2:
Students will be advised that the Zombie Research Division has learned that zombies have
a physiological way to detect heartbeats (similar to how sharks can detect electrical
impulses from muscles) that are over 120 beats per minute (BPM). The Zombie Research
Division needs to give a recommendation to survivors of how vigorously they can run from
zombies without alerting more zombies to their presence due to an increased heart rate,
and whether caffeinated beverages will pose a risk for increased zombie attention.
Students will be instructed to perform additional testing on the HR monitors and make a
recommendation to the zombie survivors.
Lesson Background Concepts for Teachers:
Day1:
Teachers will review concepts of the electromagnetic spectrum with students. To
understand how the heart-rate monitor works, it is crucial that the students understand
what infrared “light” is and its reflectivity to oxyhemoglobin. The instructions have been
created in such a way where the student does not need to know what each electrical
component is.
Day 2:
Regulation of heart rate is an important concept in biology. Human bodies regulate heart
rate via the autonomic nervous system, with the balance between the sympathetic (speeds
up HR) and parasympathetic (slows down HR) largely determining your heart rate at a
given time (other factors can contribute, such as cardiovascular health). Students will
measure the resting heart rate of their group and create an average of the entire class so
that they can compare the class average to the human population normal range. Exercise is
well known to induce increased heart rate, as respiring tissues need more blood to provide
oxygen and nutrients. The students will record the heart rate response to bursts of intense
exercise (known as interval training) and graph the results. The heart rate should start to
plateau after several minutes of vigorous exercise, and may reach the “maximum heart
rate.” Students can compare the highest recorded heart rate to an approximation of the
max HR that is often quoted as HRmax = 220 – Age(years). Finally, students will test whether a
caffeinated beverage can significantly raise HR compared to a similar uncaffeinated
beverage. While a search of the internet will bring all manner of unsupported claims of
caffeine raising heart rate, a search of the scientific literature on the subject tends to
disagree, with a substantial majority of published papers concluding that heart rate is
unaffected by caffeine consumption. In light of this, the uncaffeinated beverage serves as a
critical control, because despite best efforts, the students are likely to have HR increases
over the course of the 10 minutes between measuring resting HR, drinking a soda, and then
testing HR again. When we performed this test, we had some increases in HR across the
groups regardless of caffeination, which led us to conclude that there was no contribution
of caffeine to HR. It is good to pool all groups’ data to really illustrate this point, as this
result is counterintuitive to a lot of people. At the end, students should be able to say how
their group and the whole class HR averages compare to national average, how much
exercise it required (in minutes) to get the heart rate over 120 (zombie danger), and
whether caffeine posed a risk for increased zombies (it shouldn’t).
Procedure:
Day1: See attached lab procedure for instructor.
Day 2: See attached for PowerPoint intro and detailed lab procedure handout.
Materials List
Each group will need:
Day 1
1.
2.
3.
4.
Student Handout
Breadboard
Battery Pack and 4 AA batteries
Stage 1 and Stage 2 Kit (picture seen in attached instructor handout)
Day 2
1. Heart rate monitor build on Day 1. If the HRM is not functioning, this part of the lab
can be completed using HRMs built into smartphones or using standard pulsetaking techniques with fingers placed on the neck or wrist.
2. Timer (wall clock works fine if it’s visible to all)
3. Sodas: at least 1 caffeinated and one uncaffeinated 12-ounce can of soda per group.
Try to match the amount of sugar in each to keep the number of changing variables
down. I used regular Coca-Cola and uncaffeinated Coca-Cola.
4. Google Doc: not necessary, but made the collection of all groups’ data more efficient
To share with the entire class:
Not applicable
Safety Issues:
Day 1:
Be careful with placing Operational Amplifier (U1-U8) in correctly. Placing part in
backwards can cause melting of the breadboard and burning one’s finger.
Day 2:
When exercising, be aware of surroundings and avoid hitting things / people. Students
with heart conditions or asthma should avoid the exercise-induced heart rate experiment
(these students can time and record data). Students with sugar-related issues should avoid
the consumption of soda.
Lesson Closure:
Day 1:
Instructor goes over the “Intelligence checkpoint” with students and rewards first team
who can complete the heart rate monitor and answer all the intelligence checkpoint
questions correctly. Students must listen to and understand the attached Powerpoint in
order to answer the “intelligence checkpoint” questions. A reward of zombie bait is usually
given to the first (or all) teams to those who can answer the “intelligence checkpoint”
questions and build a functioning heart rate monitor.
Day 2:
Students are asked to finish questions on the handout, culminating with the students’
recommendations on how to avoid zombie detection using what they have learned (e.g.
how to run without getting the HR up, whether caffeine is dangerous, etc.).
Assessment:
Pre-Activity Assessment:
Day1:
To review the electromagnetic spectrum, the instructor can recall the elementary school
anagram of “ROY G BIV” to go over the color of the visible spectrum. The instructor can
then relate concept of the invisible ultraviolet “light” to be next to violet and the invisible
infrared “light” to be next to red.
Day 2:
During the PowerPoint presentation, students are asked about heart rate and it’s response
to stimuli. In the lab handout, students are asked to make predictions about the effect that
exercise and caffeine will have.
Activity Embedded Assessment:
Day 1:
The “intelligence checkpoint” questions must be answered at the end of Stage 1 before
moving on to Stage 2. The following of instructions to build the heart rate monitor and
answering of the “intelligence checkpoint” questions promotes group discussion and
thinking to answer questions together. This ensures that students hit smaller milestones
and learn something in case they cannot finish the entire lab. Instructors will sign off to see
if the “intelligence checkpoint” questions are answered correctly before letting them move
onto Stage 2.
Day 2:
Students should be actively participating in either the testing or collection of data, but
conclusions are drawn afterwards. For the exercise-induced change in heart rate, the
students may reach “zombie danger” (i.e. HR > 120BPM) before the testing finished, and
may be asked whether the test subject is in danger throughout the testing.
Post-Activity Assessment:
Day1:
In order win the “zombie antidote” (chips or any prize) students must have the instructor
sign off on whether their “intelligence checkpoint” questions are answered correctly and
have a working heart rate monitor.
Day 2:
Students were requested to finish handout questions for homework if they had not
completed them in class. These were gone over as a group (and using the graphs and
statistics from the Google Spreadsheet). Students volunteered their recommendations on
avoiding zombie detection to the whole class and there was discussion. Fellow also went
through the turned-in handouts to assess what parts needed clarification, changing, etc.
Is this lesson based upon or modified from existing materials? If yes, please specify
source(s) and explain how related:
Not provided
References:
Not provided
Attachments:
Day 1:
Heart Rate Monitor – Instructor.pdf, Heart Rate Monitor – Student.pdf, Zombie Research
Division Training.pdf
Day 2:
Zombies Day 2 Intro.pdf, Heart Rate Lab Day 2 Handout.pdf
List CA Science Standards addressed:
Day 1: Physics: Electric & Magnetic Phenomena 5e
Day 2: CA Science Standards for grades 9-12:
Students know how the complementary activity of major body systems provides cells with
oxygen and nutrients and removes toxic waste products such as carbon dioxide.