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Forensic Lesson Plan #4
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Forensic Lesson Plans
Links:
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Chromatography
This activity is a super easy
activity that requires very little
set up.
Once you have all the materials
you can alter the procedures to
fit a crime scene or simply use it
as an inquiry lesson.
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Forensic Home page
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The Old Super Glue Trick
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Whose Hair is it?
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Matching Matchbooks
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Let Me know What you
Think
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Name:
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Carlyn E. Little
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Email:
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Chromatography can be done
with lipstick too! Can You figure
out how?
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Materials Needed
Black water based markers from several different
brands You can alter this lab by changing the writing instruments or by
chancing the solution. For example some regular ink pens can be effected by
simple **cooking oil, permanent markers can be affected by **fingernail polish
remover. Have the students experiment with several writing tool and solutions.
4 tall glasses or jars or beakers, masking tape, Filter
paper or coffee filters (cut into 2.5cm by 10cm strips),
Latex Gloves, 4 straws or pencils, solution - water **,
and a ransom note Prepare this ahead of time - each sample set needs 3
markers from different companies, and a ransom note written on similar type of
filtering paper with at least 15cm from the bottom blank ( trust me this will save
you time in the long run) and three blank filter strips
Procedures
1. Put on the latex gloves.
2. Give each lab group a sample set of three different writing instruments -
three black water-based markers from three different companies, the ransom
note and three strips (2.5cm x 10cm) filter paper.
3. Students should label each marker and corresponding test filter paper as
Marker 1, Marker 2, Marker 3.
4. Each group needs to cut a strip (2.5cm x 10cm) from the ransom note,
strongly suggest that they are to cut the strip from the bottom - because they
want the written part of the strip to be near one end of the strip and the rest of
the strip blank.
5. Each group now needs to draw a dot on one end of the blank filter strips
using the markers. The dot should be half the size of a dime. Every marker will
have its own filter strip to create a dot on. There should be one dot on one filter
paper for one marker.
6. Now fill the four jars with water** about 1 cm of water.
7. Use the masking tape to tape the blank end of the strips of filter paper to
the middle of the straws like a flag.
8. Now place the strips of paper into the jars so that the tip of the paper is
touching the water. The straw should lay across the jar holding up the paper.
9. Wait 24 hours.
10. Have the students take out each sample of the marker samples and the
ransom note sample. Have them create a triple Venn- diagram of the
characteristics that are alike and different.
11. Have them try and figure out which pen wrote the ransom letter. Explain
that even though all the pens wrote in black each company has their own
unique formula, therefore we can tell by using chromatography each ink used,
because each ink has a unique pattern. The heavier inks stay down towards
the bottom of the filter paper, and the light inks have moved towards the top.