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Forensic SciencePractical Reports
Sarah Jane Cahill s3201289
Adam Roche s3303759
Rachel Zammit s3300669
Contents
Introduction 2
Revealing latent fingerprints using Magnetic and Fluorescent powder 3
Revealing latent fingerprints using Talcum and Cocoa powder 7
Revealing latent fingerprints using Gentian Violet 9
Revealing latent fingerprints using Silver Nitrate 13
Revealing latent fingerprints using Iodine fuming 15
Revealing latent fingerprints using Superglue fuming 17
Revealing latent fingerprints using Ninhydrin 19
Drug Analysis: Chemical Drug Spot Test 21
Unknown Analysis: Chemical spot test 25
Drug Analysis: Thin Layer Chromatography 28
Detecting blood using Luminol 31
Blood Splatter Analysis 33
References
Appendix 1 – Risk Assessment Sheets Book 2
Appendix 2 – MSDS Book 3
ONPS 2186 Page 1
IntroductionThe topic of forensic science as ‘solving mysteries’ was chosen for our project and to
assess whether some experiments used in the real world are suitable to bring into a
classroom setting and introduce the younger generation to the scientific understanding of
forensics.
The focus was to test a range of different forensic procedures and based on their
complexity, risk analysis and cost, determine whether they are suitable to use in a school
laboratory. Ultimately the focus will be at the VELS level 6 science streams as this is the first
to introduce the differing science streams. However, while these experiments suitability for
year 10 students is the main focus, whether they can be adapted to younger or older year
levels is also considered.
The main topics covered were: developing latent fingerprints using powder and
chemical techniques, identifying an unknown substance via chromatography and chemical
spot tests, and blood analysis through blood splatter and luminol.
The experiments we thought were appropriate to use in the classroom are written
up as lesson plans including teacher notes in a separate document.
ONPS 2186 Page 2
Revealing Latent Fingerprints using Magnetic and Fluorescent Powders
Objective
Allow students to gain valuable experience with powdered fingerprinting techniques and detect fingerprints on different surfaces
Materials
Goggles, gloves and other PPE UV glasses Black Magnetic powder White Magnetic Powder Magnetic Brush Applicator Red Flurocent powder Green Flurocent powder UV light source
Procedure
1. Rub your finger on your forehead or in your hair to produce an oily print2. Press finger lightly on one of the surfaces being examined3. Using the magnetic brush applicator, hold above the magnetic powder mixture to form the
‘brush’ 4. Lightly brush over the fingerprint on the specimen until visible 5. Return magnetic power from the brush applicator to the container6. Repeat steps 1-5 for your other specimens 7. Use the same technique for the florescent powders8. Once the fingerprint is visible with florescent powder, expose to UV light
Pictures
Green fluorescent powder on glass Green fluorescent powder on glass under UV lamp (torch) under UV lamp in dark box
ONPS 2186 Page 3
Finger print specimens on different surfaces
Plastic cup/lid Glass slide Aluminium Foil/can Polystyrene cup Black cardstock White/Glossy paper Fabric Ceramic tile
Black magnetic powder on Glass White magnetic powder on Glass (white background) (black cardstock background)
Black magnetic powder on Polystyrene cup Black magnetic powder on plastic
White magnetic powder used on White magnetic powder used on black cardstock aluminium foil
ONPS 2186 Page 4
ResultsThe results from the experiment are shown in the table below:
Test Surface Magnetic Powder Fluoro-Magnetic Powder Black White Green Red
Glass
No excess smudges on
surface. The print is visible but
smudgy
Clear and sharp print, no excess
smudges on surface (needs a
dark background)
Clear print with visible ridges
Sharp print with visible ridges
Plastic
Clear print observed,
defined patterns of fingerprint
visible
Clear and sharp print, A little background
smudge visible
Clear print with visible ridges
Clear print with visible ridges
Aluminium foil
Sharp print, no excess smudges
on surface however hard to
see on foil
Clear and defined print however
hard to see compared to black powder
Clear print with visible ridges
Clear print with visible ridges
Aluminium canVisible print, not as defined. Has
background smudges
Visible print, not as defined. Has
background smudges
Sharp print with a little
background smudge
Sharp print with a little
background smudge
Polystyrene Very defined and
clear print, no excess smudges
-Clear print with
visible ridgesSharp print with
visible ridges
Ceramic tile Sharp and clear print however smudges on background
-Defined print
however smudges on background
Sharp and clear print however smudges on background
Glossy photo paper
Sharp print with defined lines
however not very dark
-Sharp print observed however
background smudge
Sharp print observed however
background smudge
White paper Defined ridges and lines present
- Clear print with visible ridges
Sharp print with visible ridges
Black cardstock(embossed
pattern)-
Background smudge however
sharp print observed
- -
Fabric Black smudge, no visible print
White smudge, no visible print
- -
Overall we found using more oil (from hair) and pressing prints lightly on the surfaces being tested produced clearer prints. When the prints were pushed hard onto the test surface, the powder produced prints that were smudged and not well defined. The polystyrene cup produced very clear prints with no background smudge however, the texture of the cup makes the print harder to define.The florescent powdered prints were examined under different UV light sources which all work well, better in a dark environment such as the UV lamp box.
ONPS 2186 Page 5
Conclusion
This experiment would be great to use in a school setting both primary and secondary level.
Students will learn that not all surfaces will produce a clear and defined fingerprint. This exercise is
quick, clean and easy to run. The results produced are clear and non-ambiguous. The surfaces that
did not produce a clear print can be examined at a later time using chemical techniques such as
iodine fuming which may produce a clearer print. Students can also learn how to lift the prints from
the different surfaces using tape. This is explained in more detail in the “Revealing Latent
Fingerprints using Cocoa & Talcum powders” on page …… There is low risk associated with this
experiment and substances used are not very hazardous. The cost of the experiment may be
expensive as the magnetic /fluorescent powder kit must be purchased however it’s an extremely
valuable experience for students and worth the one off cost.
ONPS 2186 Page 6
Revealing Latent Fingerprints using Cocoa & Talcum powders
Materials
Glass jars Make up brush Clear packing tape (or other large width clear sticky tape) Talcum / baby powder Cocoa powder White and black paper Regular drinking straw
Procedure
9. With a clean cloth, wipe down all glassware10. With clean hands rub your earlobes between your thumb and forefinger.11. Press thumb firmly onto glass surface leaving behind a finger print.12. With the makeup brush dip into the loose powder, less is more.13. Start by flicking the powder off the brush at the finger print.14. If this does not reveal the print enough VERY lightly dab up and down with the brush on the
surface. DO NOT ‘paint’ the glass as this will smudge the print15. Once print has a light covering of powder, use straw and blow off excess.16. Repeat steps 5 – 7 until the print is clearly visible.17. In one very quick motion, pull out a length of sticky tape, 20cm – 30cm long.18. Put tape over print and press down firmly, avoid air bubble but do not press out if they occur19. Peel off in a quick but careful motion and stick down onto opposite colour paper
Pictures
Fingerprint revealed using cocoa powder Fingerprint revealed using talcum powder
ONPS 2186 Page 7
Results
After a couple of attempts using different techniques, a suitable one was discovered. A full print was
able to be lifted and transferred to a different surface for further examination. A number of factors
will vary the results, the ‘greasiness’ for the print – the powder is attaching to the oils on your finger
so rubbing the earlobes is extremely helpful but not always good enough. Technique is a very big
component in revealing the print, multiple attempts were used experimenting with different
techniques but it is still very easy to smudge the print
Multiple surfaces were also experimented with, paper, photo paper, material glass, plastic and
polystyrene. It was only the hard surfaces that were able to develop a print. Glass and plastic.
Conclusion
This experiment is suitable to use in a high school setting. The technique although not hard can be
frustrating and younger students may lose interest if results aren’t shown quickly.
The heavy handedness of younger students (primary aged) would be extremely detrimental to the
fingerprint and could be the difference between finding a print and not finding a print.
However, without the use of a magnetic fingerprinting kit this would be one of the cheapest and
cleanest options for experimentation with children.
This technique was only suitable on a solid smooth surface. Glass, tile and some plastics all revealed
a finger print. Surfaces such as polystyrene, paper, cardboard, photo paper were not able to produce
a print using the above powders.
Other options are also available where students can make their own fingerprinting powders; soot
and starch powders when mixed together are also effective.
It is quick and easy prac to set up and can be done at the beginning of the unit to introduce students
to the responsibilities of prepping, time management and cleaning their work stations appropriately.
It is an excellent base to start from in the sense that it can be made harder in different areas.
You could allow the students to dust a larger area physically looking for a finger print, as the police
would do; or after the fact, lift the print and scan it into a computer and compare it to sample prints
to determine the criminal.
ONPS 2186 Page 8
Revealing Latent Fingerprints using Gentian Violet
Materials
Different types of sticky tape A number of 400ml beakers or drinking cups Small spray bottles Funnel Crystal violet stain Water Disposable gloves Art smokes or overalls for students Protective eye wear Evaporating dish Microscope slide Tongs/forceps Magnifying glass Camera
Procedure 1
1. Put on your protective eyewear, gloves, and protective clothing.
2. Measure out .1g of crystal violet stain and add to 100ml of water and stir til mixed.
3. Pour sufficient gentian violet solution into the evaporating dish to cover the bottom to a
depth of 5mm or so.
4. Put a latent fingerprint on your first tape specimen by pressing the tape against your
fingertip and then peeling it away.
5. Place the specimen sticky side up on a microscope slide and carefully secure both ends of
the tape to the slide using additional tape.
6. Repeat steps 3 and 4 with each of your other tape specimens.
7. Using the forceps, place the first specimen face up in the gentian violet solution, and allow it
to soak for one to two minutes.
8. Using the forceps, remove the specimen from the gentian violet solution and rinse it under
cold running water for several seconds, (You can begin staining the next specimen while you
rinse the current specimen.)
9. Examine the rinsed specimen for visible fingerprints. If the fingerprints are distinct, set the
specimen aside to drain and dry. If the prints are stained only lightly, repeat the stain/rinse
cycle several times, until no further improvement is evident.
10. Place the specimen on a clean, flat surface and examine it carefully under strong oblique
light with the magnifying glass. You should see fingerprints revealed in considerable detail as
ONPS 2186 Page 9
violet stains. If you have a camera, take a photo of the developed fingerprints for your
records.
11. Repeat steps 3 through 9 for your other specimens.
Procedure 2
1. Wrap tape, sticky side exposed, around cup or large beaker
2. Press finger onto sticky side of tape and carefully peel off
3. Pour gentian violet solution into spray bottle
4. Over sink or protected area spray the finger print sample with gentian violet and allow the
sample to stand for 2 – 3 minutes.
5. Briefly rinse off with water.
6. Examine the rinsed specimen for visible fingerprints. If the fingerprints are distinct, set the
specimen aside to drain and dry. If the prints are stained only lightly, repeat the stain/rinse
cycle several times, until no further improvement is evident.
7. Place the specimen on a clean, flat surface and examine it carefully under strong oblique
light with the magnifying glass. You should see fingerprints revealed in considerable detail as
violet stains. If you have a camera, take a photo of the developed fingerprints for your
records
ONPS 2186 Page 10
Pictures
Procedure 1
Stained surface pre water rinse Stained surface after water rinse
Procedure 2
Stained surface pre water rinse Stained surface after water rinse
ONPS 2186 Page 11
Results
Up to 3 attempts were required for the print to fully develop on the electrical tape using both
methods. The packing tape was clearly visible after 2 rinses in the gentian violet. Masking tape
samples were destroyed in both procedures as soon as liquid was applied. Gaffa tape produced
prints however due to the mesh reinforcement in the tape, prints were not clear and matching them
to another print would be extremely difficult.
It was suggested a dilute HCl rinse would be appropriate for the final rinse to remove excess stain
however as you can see in the photos, it is not really needed and the probability of destroying the
print, using too high a concentration of HCl, is too high.
Conclusion
This experiment is suitable to use at the higher end of primary school through high school. The
messy nature of the stain would need to be explained and safety precautions taken.
The prac can incorporate some prep work, making the solution, and introduce time management.
As the solution stains everything it touches, students can be introduced to terminology such as
contamination, cross contamination and therefore would need to take further care in what and
where they spray. Allowing for easier clean up and limit the possibility of staining unnecessary parts
of the classroom or student.
The prac is only suitable for adhesive surfaces and even then, masking tape was not suitable.
The prep time is minimal and cost can be kept to a minimum. A few rolls of sticky tape and some
small spray bottles cost us a total of $15 at the time, everything else would be readily available in a
lab class.
Older students could take the experiment further with photographing the print, developing and
comparing it to known samples to determine the criminal
ONPS 2186 Page 12
Revealing Latent Fingerprints using Silver Nitrate
Materials
3% silver nitrate solution (0.75g AgNO3 per 25mL H2O) Spray bottle Finger print specimens on different porous surfaces such as paper Newspaper Goggles, gloves and other PPE
Procedure
20. Place the specimen on old newspaper to protect the bench21. Spay the specimen with silver nitrate solution enough to wet the surface22. Allow the specimen to air dry for 15 minutes23. Expose the specimen to direct sunlight or an ultraviolet lamp for the prints to develop. This
may take 5 minutes to an hour24. Bathe the specimen in water to remove excess silver nitrate25. Repeat steps 1-5 for your other specimens
Pictures
Faint fingerprint on paper towel
Results
The results show a print is revealed but very faint and hard to see however the print is well defined.
Results may vary depending on the surfaces used and the quality of the print. UV exposure plays a
big role in developing valuable prints. The soluble silver nitrate reacts with sodium chloride present
in sweat to produce insoluble silver chloride on the specimen being examined. The treated surface is
exposed to UV light which reduces silver chloride to metallic silver revealing the prints as grey-black
stains. Overdeveloped prints may turn the whole specimen black.
ONPS 2186 Page 13
Conclusion
This experiment takes a long time to develop and the final prints are not extremely clear. It can be
used in the classroom if need be however there are better techniques which produce faster and
clearer prints. The advantages include that there is little cost involved to run this experiment and it is
easy to set up. Silver nitrate may be successful where other development techniques have failed
(such as iodine fuming and ninhydrin) because silver nitrate reacts with the non-volatile sodium
chloride present in fingerprint residues. Old fingerprints may have lost their volatile residues (such as
water) whereas the sodium chloride residue remains. Silver nitrate is a physical developer and is
destructive. It may be used after other methods have been attempted.
ONPS 2186 Page 14
Revealing Latent Fingerprints using Iodine Fuming
Materials
Iodine crystals (a few crystals) Iodine chamber (plastic container with lid) Starch solution (1.0 g corn starch in 25mL H2O, filter off clear liquid) Spray bottle Finger print specimens on different surfaces such as paper and photo paper Newspaper Goggles, gloves and other PPE
Procedure
26. Place old newspaper to protect the bench and work must be done in the fume hood27. Sprinkle a few iodine crystals into the chamber28. Place the specimen into the chamber and seal tightly29. Using your hand, rub the bottom of the container to warm the iodine crystals30. Allow to sit for 2-5 minutes31. Extract specimen from the chamber (Dark brown orange stains are evident on the paper)32. Lightly spray with starch solution to make the prints permanent (prints turn black in colour) 33. Repeat steps 2-7 for your other specimens
Pictures
Fingerprint after iodine fuming Fingerprint after being sprayed on glossy paper with starch solution
ONPS 2186 Page 15
Results
The iodine fuming technique worked well on glossy and white paper. When the white paper was
sprayed with starch solution, the sprayed area turned brown and it was hard to see the print clearly
as it blended in with the background. When the glossy paper was sprayed with starch solution, much
better results were observed (see picture above). Only a tiny amount of spray needs to be used to
make the prints permanent. Iodine fuming works well on porous surfaces therefore only paper was
examined in this experiment. Please note that hands must not be washed before producing a print
on the specimen as it removes skin oils and salts. For best results, wipe your finger against your
forehead or nose.
Conclusion
This experiment is suitable to use in a high school setting. It is inexpensive, easy to set up, and the
prints don’t take long to develop and they show up sharp and clear. Iodine fuming is an excellent
technique that students should be exposed to which develops latent fingerprints on porous surfaces.
The advantage of iodine fuming is that the prints are only temporary. The iodine will eventually
sublime from the surface of the print, allowing the print to return to its latent state. The surface is
then returned to its original appearance and can be exposed to additional developing techniques.
ONPS 2186 Page 16
Revealing Latent Fingerprints using Ninhydrin
Materials Ninhydrin Acetone Spray container Other surface such as fabric, polystyrene cup, glossy paper, ceramic tile foil Lab coat Safety glass Gloves
Procedure 1. Make the ninhydrin solution (0.15 - 0.2g Ninhydrin dissolve in 25ml acetone)2. Make specimen by wiping fingers against forehead then pressed fingertips on blank
sheet of paper3. Spray ninhydrin solution onto paper so it is damp4. Allow to dry (at room temperature it can take up to an hour or days for stains to
appear. Accelerated at high temperature using paper towel and iron)
Pictures
. The result of ninhydrin sprayed onto a latent fingerprint on a sheet of paper
ONPS 2186 Page 17
Results
When the ninhydrin spray was sprayed on the polystyrene cup the cup began to
disintegrate. The only surface that the finger print developed on well was the piece of
paper. The print took ½ an hour to developed and showed up as a purple colour. In the
print you could see the fine lines of the finger print.
Conclusion:
This practical is appropriate for high school students because it involves a lot of chemistry.
The results produce from this practical are very good with well-defined prints. The practical
is easy to preform and if the teacher has the spays prepared would only take 10 minutes
working time and students can go on with other work while the print develops. Learning
about finger printing is an import aspects in forensic science because everyone person
excluding twins has unique finger prints for this reason finger prints has helped to solve
many crimes. However this practical does need a laboratory to be carried out which could
eliminate some schools. The chemicals in this prac may be expensive however can be
brought in bulk to reduce cost.
ONPS 2186 Page 18
Revealing Latent fingerprints
Using superglue
Materials Super glue Small container 0.5M Sodium hydroxide Glass slide/watch glass with fingerprints Paper towel Foil Cotton pad or Cotton Wool
Procedure
1. Place paper towel at the bottom of the container and pour in some water to dampen it
2. Make a little container out of foil and place in the fuming chamber with a cotton pad placed inside
3. Place microscope slide specimen into the fume container 4. Add 1-2 drops of superglue onto centre of foil pad5. Add a small amount of 0.5M Sodium hydroxide on top of the superglue to speed up
the reaction 6. Place lid onto the container, within 5 minutes fumes in the superglue should coat the
fingerprints on the microscope slide (white traces-fingerprints) 7. Can then lift with tape, dust, treat with dyes such as fluoresces to make more visible
under a different light source
Results:
It was hard to tell if the super glue had developed the finger print or if it was a print made
from oil of the finger. When the chamber was fuming other finger prints on the lid of the
container developed however these faded away quickly as well. The watch glass needed to
be place in light to be able to see the finger print
ONPS 2186 Page 19
Conclusion
To develop the fingerprint you need to use a fume hood. Acids were used are there was a
risk of fore in this practical. The results that were obtained from developing were hard to
see it wasn’t clear whether the print had been developed or if it were just an impression
from the oil on my finger. Students are already performing practical on other developments
of fingerprints that produce better results and there isn’t time within a unit to perform all
the practicals. Students can learn about the technique and use picture to see results. The
print took a long time to develop so students would have to get the results from the
practical on a different day.
ONPS 2186 Page 20
Drug Analysis: Chemical Spot TestMaterials
Reagents: Marquis Reagent – 10ml of 37%formaldehyde added to 100ml concentrate sulphuric acid Nitric Acid Reagent – Concentrate Nitric Acid Mandelin Reagent – 1 gram of Ammonium Vanadates dissolved in 100ml concentrate
sulphuric acid Mecke’s Reagent – 0.5 grams Selenous Acid dissolved in 100ml concentrate sulphuric acid
Reference Material 2-Chloroacetophenone Indole Aspirin Paracetamol Caffeine Ibuprofen
Validation material No-doz Tablet (caffeine) Panadeine powder (paracetamol and codeine, opiate)
Unknown substance for testing A number of unknowns for the students to test, to be prepared by the teacher before class
Equipment ‘well’ porcelain test plates Pasteur pipettes Pencils / paper Spatulas / icy pole sticks Colour reference chart Mortar and pestle
Safety equipment Eye protection Lab coat Gloves
Procedure
34. Label the wells of the porcelain test plates with the reference material to be tested35. Fill a pasture pipette with one of the reagents36. Carefully put 2 drops of the reagent into each of the wells on the test plate.37. Using a separate pipette, repeat steps 2 and 3 for the other reagents.
ONPS 2186 Page 21
38. Using separate spatulas, to avoid cross contamination, carefully place a small amount (enough to fit on the end of a toothpick) of the reference material and validation material into each of the reagents.
39. Slightly mix the material with the reagent and wait 5 minutes.40. After 5 minutes, note the colour change and take photos for further referencing.41. Repeat steps 5 – 7 with the unknown substance to be tested42. Compare the colours from the unknowns to the reference/validation material and make an
assumption on their contents
ONPS 2186 Page 22
Pictures
Examples of using too much reagent and getting ‘difficult’ readings to understand
Results
The results of the test were not easily determined and a lot of careful consideration was needed to
figure out the contents of the unknowns. This may have been a result of using too much reagent or
substance, or not enough.
Results we were able to obtain were:
Unknown A- Indol and 2-chloroacetophenoneUnknown B- Paracetamol and AspirinUnknown C- AspirinUnknown D- Aspirin and No Doz or Caffeine The actual contents of the unknowns :A- Indol and CaffeineB- caffeine, paracetamol and aspirin
ONPS 2186 Page 23
Photos of the drug analysis at the completion of the experiment
C- aspirin D- caffeine and aspirin
Three attempts of the experiment were done by different people and 3 separate results were
obtained. Only one was able to successfully determine the contents of the unknowns. The other two
showed evidence of using too much and too little reagent / substance.
The photos show that there are no clear definitions between some of the samples which may be
harder to decipher later on.
Conclusion
An excellent experiment for older high school students with a history of practical lab work. The
‘unknown’ mystery factor will spark interest in the students and technique required will challenge
some. It is a case of less is more, as noted in the results; too much reagent or solution gave results
difficult to understand.
Younger students may find this ‘mystery’ interesting, but the prac, as it has been written, is not
suited for younger aged students. The reagents are quite dangerous; and to have that much inside of
a class full of students would be very difficult to manage.
The reagents contain concentrate acids and poisons substances and consideration into working in a
fume cupboard would be warranted, a set up not common in most high schools. Disposal of excess
reagents and used reagents also needs to be taken into consideration. Strong acids would need
neutralization before disposal and the poisons inside are required to be collected and disposed of
appropriately.
A similar prac is available using a lot more student friendly materials, see page _______???
The cost of the setup and equipment ie reagents ingredients and reference material, would not be
cheap. Although some ingredients are available over the counter, others are more controlled and
required appropriate storage facilities, lab prep room, to obtain.
The strength of the acids made it difficult to find suitable applicators. Large quantities would be
required and at a reasonable price. Icey pole sticks were used buy the acids managed to leech out
some colour from the wood. Toothpicks may be more suitable and assist in minimising the chance of
using too much material but as we are trying to match colours, could also leech into the acid and
give false readings.
ONPS 2186 Page 24
ONPS 2186 Page 25
Unknown analysis Chemical spot test
Objective
Perform chemical analysis to identify the nature of an unknown powder.
Materials
Newspaper Goggles, gloves and other PPE Reaction plate Wax pencil or Whiteboard marker Toothpicks or Icy-pole sticks Plastic droppers 5g Powdered aspirin 5g sugar
Procedure
43. Place old newspaper to protect the bench44. Label the reaction plate like the picture below using a wax pencil or marker
C, for control, in this case is the aspirin; Su for sugar; Sa for salt; CS for corn starch
45. Place a small amount of the substance being tested into the labelled wells using a new icy-
pole stick for each material. 46. Record the physical appearance of each substance (eg: colour, crystalline etc)47. Using a dropper add a few drops of water into the wells labelled “water” and mix the
substance gently with a clean toothpick. 48. Add a few drops of sodium hydroxide to each well labelled “iron”49. Wait 5-10 seconds and then add a few drops of iron nitrate solution to the “iron” wells.50. Place a few drops of Lugol’s iodine in the row labelled “Iodine”51. Record your observations in a table
ONPS 2186 Page 26
5g salt 5g corn starch 10mL distilled water 10mL of 1M Sodium Hydroxide 10mL of 0.2M of Ferric nitrate 5mL Lugol’s iodine
Pictures
Results
The results from the experiment are shown in the table below:Aspirin Sugar Salt Starch
Appearance White powder Crystalline powder
Fine grain crystals
Fine powder
Soluble in Water No Yes No YesReaction with Iron
Blue Orange Orange Orange
Reaction with Iodine
Orange Orange Orange Dark blue/black
The results indicate that different substances act in different ways which makes it easier for a
forensic scientist to distinguish if a white unknown powdery substance is legal or not. If an unknown
substance was found at a crime scene that turned black when mixed with Iodine, we could be sure
it’s starch. If a colour change was observed when an unknown white powder reacts with sodium
hydroxide and then iron nitrate we can conclude the substance to be Aspirin as the sodium
hydroxide reacts with aspirin to form salicylic acid which then causes iron to turn blue/purple.
ONPS 2186 Page 27
Conclusion
This experiment is suitable to use in a high school setting as it gives a good introduction in chemical
analysis. Students can learn not only the principles used in forensic science but learn the chemistry
behind what is happening such as “what is solubility and why certain substances dissolve in water
while others do not?” and “why are colour changes observed? And the chemical reactions involved”.
The substances used in this experiment have a low risk associated with them compared to a
different drug analysis test that was preformed which is more suitable for experienced students (see
page …….) The cost involved is minimal as every day substance are being used and they are not hard
to obtain. This experiment can be modified slightly by using baking soda as another test substance
and the reaction with vinegar (as baking soda bubbles when added to vinegar as carbon dioxide is
being produced). The time frame to undertake this experiment is 10-15 minutes which allows time
for discussion.
ONPS 2186 Page 28
Drug analysis using Thin layer chromatography MaterialsReference material
1% w/v 2-chloroacetophenone (mescaline in ethyl acetate 1%w/v indole (LSD MIMIC) in ethyl acetate 1% w/v Aspirin in ethyl acetate 1% w/v paracetamol in ethyl acetate 1% w/v caffeine in ethyl acetate 1% w/v nurofen (ibuprofen tablet in ethyl acetate
Validation materials 1%w/v panadeine (paracetamol + Codeine (opiate)) tablet in ethyl acetate 1% w/v No-Doz tablet (contains caffeine ) in ethyl acetate
Unknown samples Unknown A dissolved in ethyl acetate Unknown B dissolved in ethyl acetate Unknown C dissolved in ethyl acetate Unknown D dissolved in ethyl acetate
Equipment required TLC plates Developing chamber Mobile phase (50:50 ethyl acetate :hexane-acidified with ~0.5% formic acid ) Filter paper (11cm) Capillary micropipettes (premade using Bunsen burner and pasture pipette) UV-lamp Pencils &rulers
Procedure 1. Prepare the developing chambers by approximately 5ml of mobile phase solvent
(50:50 v:v ethyl acetate: hexane- acidifed with ~0.5% formic acid) to the beakers 2. Cut circular filter paper into a rectangle and place into chamber to act as a wick 3. Cap each jar and allow chamber to equilibrate for 10 minutes while preparing your
TLC plates 4. Obtain enough (3) TLC plates to test the drug standards and three unknown samples 5. Using a lead pencil, lightly draw the starting postion by a pencil line ~1cm from the
bottom of the plate. Mark five positions on the plate with pencil and be sure to label what each spot represents
6. Obtain a capillary micropipette for each drug standard and your unknown samples 7. Immerse the end of the capillary micropipette into the vial until some of the sample
is drawn in 8. Allow the drop at the end of the capillary to gently touch the plate on the starting
line. Keep the spots small (~2mm) and concentrated by applying the sample 2-3 times and allowing the spot to dry between applications
9. Repeat this procedure for each of the samples being tested10. To each plate, apply 3 drug standards and an unknown drug sample 11. Place the TLC plate in the chamber using forceps 12. Allow the solvent front to reach a level about 1 cm from the top of the plate
ONPS 2186 Page 29
13. Remove the plate from the chamber and mark the position of the solvent front immediately. Set the plate on paper towel in the fume hood to dry
14. Visualize the spots by illumination under a UV lamp 15. Trace around the each spot lightly and mark the middle using a pencil. 16. Measure the distance travelled by each component in the results section 17. Calculate the RF values. Record them in your notebook
Results
Results were disposed by3rd party
Conclusion
The chromatography practical that was carried out isn’t appropriate for high school student
because of safety reasons; the chemicals involved were concentrated acids. Acids are a
safety problem because they can burn your skin. It’s also not appropriate because the
components in the mixture didn’t separate well and it was hard to tell if there was one dot
or two dots. Also T.L.C plates can be expensive depending on how sensitive they are. The
development of the plate needed to be done in the fume hood and looked at with a U.V
light box so this may excluded schools that don’t have a science lab from doing this
practical. Even though this particular chromatography practical isn’t appropriate
chromatography is still an important concept for the students to learn. Chromatography can
be used to identify an enormous range of substances; it can also be used to separate a
mixture of substances. If a student was going to study science then it is important that they
have an understanding of chromatography and how it is used. Chromatography relies on an
understanding of polarity, which is an important concept in chemistry. Chromatography and
polarity are studied in VCE chemistry so by having a chromatography practical in a forensic
science unit it introduces the topic without having the pressure of VCE, it also gives
relevance and interest to chromatography. According to the Victorian certificate of
education study design accreditation period 2007-2014 unit 3: chemical pathways outcome
1 key knowledge points “principles and applications of chromatographic techniques and
interpretation of qualitative and quantitative data from thin layer chromatography (TLC),
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high performance liquid chromatography (HPLC) and gas chromatography (GC);” Victorian
certificate of education study design chemistry. A Chromatography practical that would be
appropriate for a year 10 level would be using paper chromatography to separate the
different colours in black pens. This practical is a lot safer for year tens as there are no
hazdours materials being used. The results for a practical will be a lot easier to see because
you are separating out colours. It can take some time for the solvent to reach the to of the
paper and separate the colours however the students can start the practical and run it
continue with other work while keeping a eye on their practical.
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Revealing Latent Blood stains with Luminol Materials
Rags Spray bottles Luminol Potassium Hydroxide Hydrogen Peroxide Potassium Ferricyanide solution Water Beakers Measuring cylinder Glass rod Safety glasses Gloves Camera
Procedure
52. Put on all safety equipment53. Measure out 2 grams of Luminol powder and add it to 15 grams of Potassium Hydroxide in a
large beaker.54. Add in 250ml of water and stir thoroughly. 55. In a separate beaker make a 1:1 mixture of the luminal solution from step 2 and 3%
Hydrogen Peroxide56. Pour this mixture into a spray bottle.57. Take some old rags and pour small amounts of Potassium Ferricyanide solution on them and
set aside to dry58. When rags are dry, in a darkened room spray the Luminol solution onto the rag and
photograph where the glows appear.
Pictures
Rag stained with Potassium Ferricyanide solution Same rag sprayed with the luminol solution
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Results
The experiment worked as predicted. A blue glow from the Luminol solution and the iron in the
Ferricyanide was seen but only in darker surroundings. At normal room light the ‘blue’ glow was
more of a pale yellow liquid.
Conclusion
The experiment worked extremely well and would be exciting for students from primary to middle
high school on the ‘cool’ factor alone. It could be made more interesting for older students if told to
bring in old articles of clothing to see it latent blood could be found ie football jumpers.
The experiment could also be taken out of the ‘forensic science’ category and used as a standalone
prac and introduce or continue the students learning on chemical mechanisms. A way of keeping
interest or sparking interest on what could normally be seen as a difficult or boring subject matter.
The hardest part with the experiment would be the darkness factor. Finding a room dark enough to
conduct the experiment yet maintain the safety of a large(ish) class size would normally be difficult
in a school. Blinds may not be enough to dull the light and if your only option is to take small groups
into a storage cupboard or something similar, then a suitable supervisor is required for when you are
not in the class room.
It is a gentle way of introducing what could normally be a difficult subject for some. It is not
uncommon for people to feel squeamish at the sight of blood or accidents, so care must be taken
when describing the use of the experiment in the real world.
The initial cost of the experiment would be no more expensive than any other experiment, but
ingredient could be purchased in bulk and stored for next time. Students could bring in their own
spray bottles and clothing or rags to minimise cost to the teacher and or school
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Blood splatter analysis: effect of height and surface
Materials Newspaper Pipette 175g cornflour 75mL water 175mL golden syrup 3 teaspoons red food coloring 1 teaspoon green food coloring container for mixing mixing implement (spoon, stick etc) Measuring tape or ruler Bucher paper Different surfaces such as glass, metal, carpet, plastic bag, paper, cardboard, wood,
sand paper. Lab coat and glasses
Safety equipment Eye protection Lab coat Gloves
Procedure
1. Attach the dropper on the stand so it is X cm, e.g.10cm above the sheet of paper (on a pile of newspaper) labelled 10cm.
2. Arrange the paper under the dropper so the first trial droplet lands under the label Trial 1.
3. Drop one droplet onto the paper.4. Shift the paper so the paper is positioned for the second droplet to land on the paper
under the Trial 2 label etc.5. Repeat for trial 3.6. Remove the paper and allow it to dry.7. Move the dropper on the stand so it is 20cm above a second sheet of paper labelled
20cm.8. Complete 3 trials at 20cm.9. Do 3 trials at each height suggested on Table 1. The “height column” on the student’s
worksheet has been left blank.10. When the sheets with the 3 trials at each height are dry, measure the diameter of each
droplet in mm and complete Table 1.11. Graph the average diameter of droplets from each height.
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Method for surface 1. Attach the dropper on the stand so it is a standard height and angle, e.g. 30cm, at 60o
above the target surface. Choose the height and angle.2. Arrange the newspaper under the dropper so the droplet lands in the target area.3. There will be 3 trials for each surface.4. Students should include a standard – what they will compare the different surfaces to.5. Place the first experimental surface to be tested under the dropper. Divide the surface
into 3 trial areas.6. Drop one droplet onto the surface for Trial 1.7. Shift the target surface so it is positioned for the second droplet to land in the Trial 2
zone.8. Repeat for Trial 3.9. Remove the surface and allow it to dry.10. Repeat with the different target surfaces.11. Keep the height the same.12. When the bloodstain patters are dry, measure the diameter of each in mm and
complete Table 2. On the student worksheet the “surface column” has been left blank.13. Graph the average result from each different surface.
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Pictures
Results
Table 1: effect height has on diameter of bloodstains
HEIGHT (CM) Diameter drop 1(mm) 10 820 1130 1340 1580 11100 13150 15200 14
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Table 2: the effect of different surfaces on the bloodstains
Surface Trial 1 diameter (mm)
Trial 2 diameter (mm)
Trial 3 diameter (mm)
Shape and observations of stains
Carpet 5 5 5 Soaked the blood, no splatter observed blood spot was quite small in diameter
Metal 10 9 12 Splatter was observed shape of blood splatter wasn’t round
Cardboard 13 13 14 Flattened no splatter
Fabric 9 9 1 No splatter Plastic bag 10 9 10 Splattered
When this practical was attempted the pipette that was used wasn’t delivering
large enough drops of blood to get results that were different enough to measure
using a tape measure, when dropped from various heights. We believed the
blood made up was to thick and this is why we didn’t get uniform results to
overcome this problem water was added to the blood mixture when this was
done and the practical re attempted the results were a lot better and could
visually see the difference in blood drops. However when we used the watered
down blood on the different types of surfaces this changed the results
dramatically because there was more water content the carpet fabric and
cardboard didn’t experience any blood splatter. This was not expected
according to the asistm forensic investigations unit as all of these surfaces are
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rough they should have experienced blood splatter.
Conclusion
This practical is very safe to perform, as there are no hazardous materials being
used such as acids. The biggest risk in this prac would be if a student in your
class contained an allergy another minor risk is getting stains on clothes and
floors. The items used were household items, which are readily available
meaning that this prac could be performed in all schools even if they don’t have
a laboratory. This is a real advantage because it means low social economic
schools aren’t being discriminated against. The practical only took about 20
minutes to preform which means that it’s suitable for high school as they only
have 40 to 90 minute lessons. The practical is straightforward with easy to
follow instructions. The cost of the practical is very low. The prac is very
relevant to forensic science because a lot of murder scenes contain blood
splatter; the blood splatter also gives the investigators a lot of clues about how
the crime has been committed. For example if the blood splatter were one of
high velocity then the splatter would have come from a high velocity weapon
such as a gun. This Practical also links with other areas in the forensic science
unit such as the liumenol experiment and DNA as blood contains DNA. It also
links in with other areas of science such as density, forces surface tension. This
prac requires observation skills and measuring skills, which are important
aspects of high school science.
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Appendix 1Risk Assessment Sheets
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Appendix 2MSDS
(Chemicals listed in alphabetical order)
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