2. Why teach this unit?
This course is designed as an elective course that is also considered as a career pathways class
that helps students determine what they would like to focus on in college. In general I teach all
of the topics of the class for two main purposes. The first purpose is to make the class as
interesting and realistic as possible and the second is to strengthen the science background of
students within the class. One of the difficult things to do in science is to apply knowledge to
real situations. I am teaching this particular unit to strengthen the conclusion portion of lab
write-ups and improve the ability of students to apply knowledge to situations. Additionally,
students should also gain an appreciation for the work required for careers in Forensic science.
Audience:
I have designed this unit for my Forensics class at Tualatin High School. This class can fill
several requirements for students and thus I have a very diverse population of learners.
1. Career pathway: Students in this category are generally the students that have a major
interest in becoming a forensic scientist some day. They generally tend to be fully
invested in every activity that I do in class. They may or may not be the highest achieving
students in other classes but I can count on them doing very high quality work due to the
high level of interest and motivation.
2. General elective: The students that take this class as a general elective have a very
diverse ability level. Many of the students that choose Forensics do so because they want
to take an interesting class that doesn’t challenge them too much academically. Many of
them know me from previous classes and choose the class because they like me as a
teacher. They are generally very motivated to do well and put forth maximum effort.
Many of them, however fit into the IEP category. They have difficulties in any number
of typical school activities and need some form of modification including shortened
assignments, alternative test taking, copies of notes, or peer tutors. My forensics classes
have the highest percentage of students on IEPs of all of my classes.
3. Science credit: Most of the students taking forensics for science credit are doing so
because they have failed in the other science classes they have attempted. They are
generally not the most self-motivated and have a lack of confidence in their abilities; they
also tend to procrastinate more than most students. They usually have the lowest ability
level in reading, math, and overall science lab skills.
4. TAG: I have students that are considered Talented and Gifted in numerous ways and I
need to provide a stimulating and rigorous curriculum that meets the needs of those
students.
5. ELL: I generally have English Language Learners that fit into any or all of the above
categories so it is important that I use vocabulary that does not exclude them from
understanding something. It is rare that I have a low level ELL student, however,
because this class has only sophomores, juniors, and seniors. I have had to make
modifications in the past for some students.
3. Objectives and Sequencing:
Lesson 1: Introduction to Blood Spatter
Overriding objective: Students will determine the direction of blood spatter with 100%
certainty.
I would like to start the unit with an inquiry lab that introduces the idea of blood spatter.
Students will be broken up into small groups of 3. Each group member will rotate between an
observation recorder, drawer/photographer, and performer of the lab. Each lab group will
become familiar with blood spatter by performing labs and making observations at three stations.
I will demonstrate what I would like for them to do at each station prior to sending them into the
lab.
1. Drip Drop Station:
Station one will be a simple set-up of pipettes, simulated blood and butcher paper. Students will
be asked to use the pipettes to make blood drops from different heights while keeping some
drops separate and allowing some to drip on top of each other. They will be making
observations and caliper measurements continually throughout the process.
Psychomotor Objective: After watching the instructor, students will create imitated
blood drops using the pipettes.
Cognitive Objective: After performing the lab, students will describe and draw the
differences in size and shape of blood drops expelled from the dropper.
Cognitive Objective: After completing this activity, students will describe what a
blood drop looks like when dropped from 90 degrees, or straight down.
2. Blood Spray Station:
Station two will get messy! The set-up will include paintbrushes, simulated blood and butcher
paper. Students will be asked to dip the brush in the blood and swing away at several different
velocities…slow, medium, and fast. They will be making observations continually throughout
the process.
Psychomotor Objective: After watching the instructor, students will create imitated
blood spatter using the brushes
Cognitive Objective: After completing the lab, students will draw the differences in
size and shape of blood drops released at different velocities.
Cognitive Objective: After completing the lab, students will describe the differences
in size and shape of blood drops released at different velocities.
Cognitive Objective: After performing the activity, students will draw the shapes of
blood drops moving from left to right and right to left.
4. Cognitive Objective: After performing the activity, students will describe the
shapes of blood drops moving from left to right and right to left.
3. Splat and Splash Station:
The final station will have a set-up of pie plates filled with simulate blood and some different
utensils used to smack down into them…they will be enclosed in some type of box with three
sides to catch all the spatter directions. The actual utensils need to be researched a bit first but I
am thinking a spatula, wooden spoon, and the flat side of a meat tenderizer.
Psychomotor Objective: After watching the instructor, students will create imitated
blood spatter of blunt force trauma.
Cognitive Objective: After completing the lab, students will describe and draw the
differences in size and shape of blood drops they see along the sides of the enclosure.
Once they are finished with the lab and the clean-up, I will bring them back together and ask
them to graph the information from station 1 and discuss the effects of height, velocity, and
direction on blood drops. Each group will then pair up with another group and discuss their
findings. They will be asked to add additional observations and information to each lab if it is
needed. I will then show a short PowerPoint describing the observations I made and how the
observations relate to the objective.
Homework: The small groups will write a collaborative conclusion describing the effects of
height, velocity, and direction on blood drops using Google docs.
Lesson 2: Determining Impact Angle of Blood Drops
Overriding Objective: Students will determine the angle of impact of a blood drop within 5
degrees.
For this objective I will demo the lab set-up, which will be a piece of cardboard, covered with
butcher paper and taped to the lab station. Students will use a protractor to lift the board at
certain angles. They will then drop simulated blood onto the board with a pipette and measure it.
The data will include the actual angle, the drop length, and the drop width. Students will
measure drops from 90o through 0o using the protractor as a guide. Students will then calculate
the angle based on the measurement they attained using the width divided by the length and
applying the resulting decimal to a sin table (they can also use a calculator if they would like).
Students will write a conclusion to compare the calculated angle with the measured angle and
determine the percent error involved.
Psychomotor Objective: After setting up the lab, students will accurately recreate
simulated angles using the lab set-up and a protractor.
Psychomotor Objective: After dropping simulated blood, students will accurately
measure the length and width of blood drops within a range of 1 millimeter
(+ or – 1) in order to determine the angle of impact.
5. Cognitive Objective: After taking measurements, students will apply the following
mathematical relationship: angle = arc sin [drop width/drop length] using either a
calculator or a sin table.
Cognitive Objective: After applying the mathematical relationship, students will
compare the actual measured angle to the predicted mathematical angle and discuss
any discrepancies using logical analysis.
Homework: Finish conclusion and error analysis
Lesson 3: Determining the Point of Origin of an Attack
Overriding Objective: Students will apply the principles of blood spatter to determine the
point of origin of an attack with 10% error or less.
I will start this objective by demonstrating how to run a string from a blood drop using my
measurements, a sin table, a string, tape, and a protractor.
In the final lab for the unit I will set up stations with predetermined angles and points of origin.
Students will have to use the knowledge learned from previous labs, discussions and
demonstrations to determine the direction of the blood spatter, the angle of impact of the drops,
and ultimately the point of origin. They will measure the height from the ground and distance
from the wall for the point of origin and take a photograph of the intersecting strings. I will
assess them based on the accuracy of their determined point of origin.
Cognitive Objective: Using a pre-made, mock crime scene, students will apply
knowledge to determine the angle of impact of 6 blood drops.
Psychomotor Objective: After the demonstration, students will accurately “string
up” a mock crime scene to determine the point of origin of an attack within 10%
error.
Affective Objective: Students will describe the importance of teamwork in this lab
and relate it to the professional world of Forensics.
Evaluation of Instruction:
As with most labs in science I think there are two major possibilities for struggle in these
activities. The first struggle generally comes with the application of ideas. I will try to alleviate
those issues by doing thorough demos and allowing time for practice in small groups. I will
walk around for further instruction as well. The second issue generally comes in the summary of
concepts. This is an issue that has many points of origin such as a lack of writing ability or, in
some cases, a total lack of understanding of the topic. I anticipate a wide variety of within the
summary of information, but I think that I can use the other parts of my assessment to observe
whether or not learning is taking place.
6. Blood Spatter Rubric
CATEGORY 4 3 2 1
Drops are clear and Drops are
Recreating accurate and make the inaccurate and do
N/A N/A
Blood drops analysis easier to not facilitate
understand. analysis
A description is made and
A description is made and A description is made but
the relationship between
Analysis and the relationship between there is no analysis of the A very simple
the variables is discussed
Description of the variables is discussed relationship between the description is
but there is no analysis of
Drops and trends/patterns variables, patterns or trends given.
patterns or trends based
logically analyzed. based on the observations.
on the observations.
Clear, accurate drawings
are included and make the
Drawings of Drawings are
analysis easier to Drawings are accurate and Drawings are included and
Spatter Straight present but
understand. Drawings are are labeled neatly. accurate but not labeled.
Down inaccurate
labeled neatly and
accurately.
Spatter is
Spatter is accurate and
Recreating inaccurate and
N/A N/A makes the analysis easier
Blood Spatter does not facilitate
to understand.
analysis
Clear, accurate drawings
Drawings of are included and make the
Drawings are
Spatter at analysis easier to Drawings are accurate and Drawings are included and
present but
Different understand. Drawings are are labeled neatly. accurate but not labeled.
inaccurate
Velocities labeled neatly and
accurately.
A description is made and
A description is made and A description is made but
Description of the relationship between
the relationship between there is no analysis of the A very simple
Spatter at the variables is discussed
the variables is discussed relationship between the description is
Different but there is no analysis of
and trends/patterns variables, patterns or trends given.
Velocities patterns or trends based
logically analyzed. based on the observations.
on the observations.
Clear, accurate drawings
are included and make the
Drawings of Drawings are
analysis easier to Drawings are accurate and Drawings are included and
Spatter in a present but
understand. Drawings are are labeled neatly. accurate but not labeled.
Given Direction inaccurate
labeled neatly and
accurately.
A description is made and
A description is made and A description is made but
the relationship between
Description of the relationship between there is no analysis of the A very simple
the variables is discussed
Spatter in a the variables is discussed relationship between the description is
but there is no analysis of
Given Direction and trends/patterns variables, patterns or trends given.
patterns or trends based
logically analyzed. based on the observations.
on the observations.
Recreation of Drawings are
Drawings are included and
Blunt Force N/A N/A present but
accurate but not labeled.
Trauma Spatter inaccurate
7. Angles are accurate and
Recreating Angles are
N/A N/A make the analysis easier to
Angles inaccurate.
understand.
Blood Drop Measurements are Measurements are Measurements are accurate Measurements
Measurements accurate within .01 cm. accurate within .03 cm. within .05 cm. are inaccurate
No calculations
Some calculations are
All calculations are shown Some calculations are are shown OR
Mathematical shown and the results are
and the results are correct shown and the results results are
Calculations correct and labeled
and labeled appropriately. labeled appropriately. inaccurate or
appropriately.
mislabeled.
Determination Angles are accurately Angles are
N/A N/A
of Drop Angles measured within 5 degrees measured but
Illustrates
inaccurate
Illustrates an accurate and Illustrates an accurate Illustrates a limited
understanding of
thorough understanding of understanding of most understanding of scientific
String-up of Lab scientific
scientific concepts scientific concepts concepts underlying the
concepts
underlying the lab. underlying the lab. lab.
underlying the
lab.
Summary describes the
skills learned, the Only an arbitrary
Summary describes the
information learned and summary is
information learned and a Summary describes the
Summary some future applications written and not
possible application to a information learned.
to real life situations much is
real life situation.
including the importance described
of teamwork
