Lesson Title: It’s all in the Ink!

Lesson Objectives:

Students will be able to:

a)      Comprehend the differences in pen inks

b)      Test the way inks spread when contacted with liquid

c)      Dissect ransom notes and test for commonalities between ink types

d)      Apply knowledge of material to class crime scene

e)      Identify and define the day’s vocabulary: chromatography, solute, solvent

State Standards:

      The state standards addressed in this lesson include 3.4.7., section A, which states that the students will be able to “describe and conduct experiments that identify chemical and physical properties”, and 3.4.7, section C, which states that the students will be able to “identify and explain the principles of force and motion”.

Anticipatory Set:

            To begin the lesson, show a clip from a prerecorded CSI episode, which demonstrates the crime scene investigators using chromatography within their laboratory.  After showing this, explain to the class that today they will be focusing on the subject of chromatography, and how all inks have certain properties when contacted with a liquid.

Materials:

▪Ransom note pieces, cut out of filter paper

▪At least five different pens, all with different ink

▪Fingernail polish remover with acetone

▪Filter paper

▪Scissors

▪Containers to hold remover

▪CSI Journal

Directions:

I.                    Ask if students have ever seen what happens when washable markers on paper come in contact with water (ink spreads)

II.                 Connect it to chromatography testing in crime labs

III.               Explain ransom note experiment

a.       Ransom note was found

b.      Five different pens are possible writers

c.       Need to test the five pens against the ransom note ink to find out which one wrote it

IV.              Test time

a.       Have students work in small groups of 3 or 4

b.      Model for them what they are supposed to do

1.      Cut up filter paper

2.      Use a different pen to draw on filter paper

3.      Dip the ink of each in the nail polish remover

4.      Let dry

5.      Dip a portion of the ransom note in nail polish remover

6.      Compare ransom note ink results with the five tested

V.                 Wrap up

a.       Ask for scenarios where this type of testing could be useful

b.      Explain this lab’s connection with the Handwriting Analysis lab

VI.              CSI Time

a.       Have the students finish up the experiment with the evidence collected from the class crime scene

b.      Each student will return to their desks and write their findings/notes about the chromatography results in their CSI Journal

Adaptations:

            If a student in the class has disabilities, you (the teacher) could assist them with their findings, or pair them up with a dependable student.  Encourage safety and carefulness with the scissors, nail polish remover, and containers holding the remover.

Assessment:

            At the end of the week, you will have two tests: First, a written one, which includes the vocabulary covered in the unit.  The second test will be a Practical, in which you take one student at a time and pick one of the five branches of forensic science that you covered, and have the student answer prompted questions about procedure and findings.

Assignment:

            Finish defining vocabulary, if it was not completed in class.  If desired and time permits, have the students create new experiments, where they can test for ink from pens or markers.

Closure:

            Encourage the students to put this into practice at home or with friends, by making their own experiment (as aforementioned in the “Assignment” section).