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Table 3 – Microscopic Examination Of Soil Results – Large Sand Particle Color Counts
Blacks Reds/
Pinks Whites
Yellows/
Browns Others Clear
Reds/ Pinks Milky Whites Yellows/ Browns Other Total Sand Particles Counted Farm Soil 0 3 1 25 4 15 7 30 10 2 97 Vehicle #1 3 0 10 100 1 4 0 4 3 0 125 Vehicle #2 0 5 7 100 0 3 0 2 0 0 117 Vehicle #3 16 2 0 50 4 29 20 46 20 1 188 Vehicle #4 0 0 2 100 0 10 0 40 5 0 157
SOLID/OPAQUE COLORS TRANSLUCENT/CLEAR COLORS
Table 4 – Microscopic Examination Of Soil Results – Large Sand Particle Color Percentages
Blacks % Reds/ Pinks % Whites % Yellows/ Browns % Others % Clear % Reds/ Pinks % Milky Whites % Yellows/ Browns % Other % Farm Soil 0% 3% 1% 26% 4% 16% 7% 31% 10% 2% Vehicle #1 2% 0% 8% 80% 1% 3% 0% 3% 2% 0% Vehicle #2 0% 4% 6% 85% 0% 3% 0% 2% 0% 0% Vehicle #3 9% 1% 0% 27% 2% 15% 11% 24% 11% 1% Vehicle #4 0% 0% 1% 64% 0% 6% 0% 26% 3% 0%
SOLID/OPAQUE COLORS TRANSLUCENT/CLEAR COLORS
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Table 5 – Characteristics of sand particles.
Sand Particles Have Mostly: *Rounded Edges
*Sharp Edges
*Some Rounded/Some Sharp Edges
Weight Of Larger Soil Particles (g) Weight Of Smaller Soil Particles (g) Total Weight Of All Soil Particles (g) % Of Larger Soil Particles In Soil Sample % Of Smaller Soil Particles In Soil Sample Farm Soil ROUNDED 0.84g 0.91g 1.75g 52% 48% Vehicle #1 CHIPPED 1.73g 0.82g 2.55g 68% 32% Vehicle #2 CHIPPED 0.99g 0.2g 1.19g 83% 17% Vehicle #3 ROUNDED 1.11g 0.91g 2.02g 55% 45% Vehicle #4 CHIPPED 1.24g 0.23g 1.47g 84% 16%
Farm Soil Vehicle
#1 Vehicle #2 Vehicle #3 Vehicle #4 Soil Texture Soil pH Color Of Soil Unusual Material In Soil
UV Light Results Large Sand Particle
Color Percentages Sand Particle Edges
% of Large And Small Soil Particles
Table 6 – Summary of soil test results. Which vehicle’s soil most closely matches the Farm Soil? (dots indicate a close match to the Farm Soil)
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QUESTIONS – SOIL AS EVIDENCE NAME____________________________________ Use your analysis of the Farm Soil Sample and Vehicle Soil Samples to answer
Questions #1 - #6
1. Did you discover a Vehicle Soil Sample that you believe is a perfect match to the Farm Soil? (yes or no)
_______________
2. If you answered “Yes” to Question #1 – Which vehicle contained soil that perfectly matched the Farm Soil?
_____________________________________
If you answered “No” to Question #1 – Which vehicle (or vehicles) contained soil that was the closest match to the Farm Soil?
____________________________________
3. Which person would you most likely search out as a prime suspect in the farmhouse robbery? (give their name)
____________________________________
4. List the test (or tests) you considered to be the MOST useful in helping you match the Farm Soil to the soil located on one of the a vehicles.
5. List the test (or tests) you considered to be the LEAST useful in helping you match the Farm Soil to the soil located on one of the vehicles.
6. Do you think your MOST useful test list (from Question #4) and LEAST useful test list (from Question #5) would stay the same every time you tried to match up evidence soil samples? (yes or no)
________
Explain your answer.
KEY
YES – UNLESS A GROUP’S TESTS REVEAL A CLOSE MATCH, BUT NOT PERFECT (THEY MAY ANSWER “NO”)
SHOULD BE VEHICLE #3
SHOULD BE VEHICLE #3
JOSH SILT
ANSWERS WILL VARY DEPENDING ON THE CHARACTERISTICS OF THE SOIL SAMPLES YOU ARE USING.
ANSWERS WILL VARY DEPENDING ON THE CHARACTERISTICS OF THE SOIL SAMPLES YOU ARE USING.
WITH SOME SAMPLES THE SOIL’S COLOR MAY BE THE MOST USEFUL TEST TO MAKE A MATCH – ESPECIALLY WHEN THE REMAINING TESTS HAVE SIMILAR RESULTS. HOWEVER, ANOTHER GROUP OF SOILS MAY HAVE THE SAME COLOR, BUT EACH MAY HAVE A DIFFERENT pH – MAKING pH THE MOST USEFUL TEST TO MAKE A MATCH. THE MOST USEFUL TEST CAN BE DIFFERENT DEPENDING ON THE CHARACTERISTICS OF THE SOIL SAMPLES BEING TESTED.
SHOULD BE “NO”
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7. Explain how can you tell the difference between Sand, Silt, and Clay?
8. You complete a Soil Texture Test and find THREE different soil particle layers in the soil texture tube.
Which soil particle would be found in the top (uppermost) layer?____________________ Which soil particle would be found in the middle layer?_____________________
Which soil particle would be found in the bottom layer?_____________________
9. Describe how soil might be collected and used as evidence at the following crime scenes you are investigating.
9A. You are investigating the possibility that several horses discovered in a trailer were stolen from a stable 150 miles away. Describe how soil could be collected and used as evidence in this case to help prove the horses were stolen from the stable.
9B. A body has been discovered in a wooded park. You believe the victim may have been murdered in another area of the park, then moved to this location. Describe how soil could be collected and used as evidence in this case to help prove the victim was murdered in another area of the park.
9C. A suspect has been arrested for murder, however, the victim’s body has not been located – and the arrested suspect refuses to talk. A search of the suspect’s car turns up a shovel covered with fresh dirt and a pair of muddy boots. Describe how soil could be collected and used as evidence to help locate the body of the victim.
BY SIZE - SAND PARTICLES ARE THE LARGEST, SILT PARTICLES ARE MIDDLES SIZED, AND CLAY PARTICLES ARE THE SMALLEST
CLAY SILT
SAND
SOIL SAMPLES COULD BE REMOVED FROM THE HORSE’S HOOVES OR THE TRAILER FLOOR AND COMPARED WITH A SOIL SAMPLE FROM THE STABLE TO SEE IF THERE WAS A MATCH.
LOOK FOR SOIL SAMPLES ON THE VICTIM’S SHOES OR CLOTHES AND
COMPARE THESE WITH A SOIL SAMPLE TAKEN FROM THE AREA THE VICTIM WAS DISCOVERED. THE VICTIM MAY HAVE BEEN MURDERED IN ANOTHER AREA OF THE PARK IF THE SOIL SAMPLES DO NOT MATCH.
REMOVE AND ANALYZE SOIL SAMPLES FROM THE SHOVEL AND BOOTS IN THE CAR. SAMPLE AND ANALYZE SOILS FROM DIFFERENT LOCATIONS IN THE SURROUNDING AREA IN AN ATTEMPT TO FIND A MATCH. THE VICTIM MAY BE BURIED SOMEWHERE IN THE AREA WITH MATCHING SOIL.
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10. You are talking to a rookie C.S.I. agent describing a crime you solved several years ago. You explain that the crime scene contained a sample of soil and you decided this soil evidence must have come from the suspect’s muddy shoes. You took a closer look and noticed some sort of plant, animal, or human product material in the soil sample. You quickly identified this unusual material in the soil sample, and you immediately knew where you should go searching for the person that committed the crime. Sure enough, this material allowed you to narrow your search down to a more specific location - and within a day you had a suspect in custody. The rookie is
impressed and asks you what you found in the soil, and how it helped you narrow down the location of your search. Finish the story below (be creative – there is not one correct answer) and tell the rookie what you found in the soil sample and how it helped you narrow down the location of your search.
11. Return you thoughts back to the farmhouse robbery you solved in this Training Lab. List any unusual material (plant, animal or human product material) you observed in any of the Vehicle Evidence Soil Samples (list “None” if nothing was observed in a sample). Then, based on any unusual materials you observed, attempt to describe a general location where you think this soil sample may have come from.
Unusual Plant, Animal, or Human Product Material Found
In Soil Sample
Possible Location Where Soil Sample Originated Vehicle #1 Soil Sample Vehicle #2 Soil Sample Vehicle #3 Soil Sample Vehicle #4 Soil Sample
STUDENT ANSWERS WILL VARY, HOWEVER, THEIR STORY SHOULD TELL OF SOME PLANT, ANIMAL, OR HUMAN PRODUCT FOUND IN THE SOIL THAT MADE IT OBVIOUS WHERE THE SOIL’S SOURCE WAS LOCATED.
EXAMPLE: A SMALL SECTION OF A PINE NEEDLE WAS DISCOVERED IN THE SOIL SAMPLE AND EVERYONE IN THE AREA KNOWS THE ONLY PINE TREE FOR MILES AROUND IS FOUND IN KRISTEN HANSEN’S BACK YARD. KRISTEN SAYS SHE RECENTLY HIRED JACK LANDERS TO PAINT THE PRIVACY FENCE IN HER BACK YARD. WHEN CONFRONTED, JACK LANDERS ADMITTED TO COMMITTING THE CRIME. CASE CLOSED!
ANSWERS WILL VARY DEPENDING ON THE SOIL SAMPLES YOU USE OR IF YOU ADD UNUSUAL MATERIAL TO ANY OF THE SOIL SAMPLES (SEE TEACHER NOTES). EXAMPLES OF SOME THINGS THAT COULD BE LISTED: LEAVES, SEEDS, GLASS PIECES, BRICK PIECES, ANIMAL HAIR, ETC.
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REFERENCE PAGE/TRAINING LAB – PLANT POLLEN AS EVIDENCE
NAME___________________________________________ Background: Leaves, flowers, stems, and roots – these are plant parts that are obvious
and easiest to observe. However, there is one part of a plant that can help solve crimes, yet is practically invisible – POLLEN! What is pollen? Where is it found? How can pollen help solve a crime? This Training Lab is all about pollen – and how it can be used as an
important forensic tool
1. You will be trained to identify the different flower structures and understand
their functions.
2. You will be trained to observe and identify pollen grains from the flowers of different plants.
3. You will be trained to interpret pollen grains found at a crime scene or discovered on a suspect – and use this information to help solve the crime.
Reference Page – Pollen
*A flower is a plant’s reproductive organ.
*Pollen grains are a plant’s male reproductive cells. They are produced in the plant’s flower and are eventually released into the air, or are picked up by animals that come to feed on the flower’s nectar.
*Pollen grains by themselves are very small, microscopic cells.
*A group of pollen grains together, however, is usually easy to see. A large concentration of pollen grains, like you might get by rubbing against a flower, usually forms a very fine, yellow powder that is often difficult to remove from clothing.
*Pollen grains can help you identify where a suspect, a victim, or an object has been. This is because pollen grains from different plants have different shapes, which makes it possible to identify types of pollen grains. Pretend you collect pollen grains from a suspect’s clothes.
1st – Observe the shape of the pollen grains.
2nd – Identify the kind of plant the pollen grains came from (pretend you identify
them as Oak Tree pollen.
3rd – You know the suspect has been around blooming Oak Trees.
*Pollen grains can help you identify when a suspect, a victim, or an object was in an area. Many plants bloom only at specific times of the year, which means a plant’s pollen will only be in the air at specific times of the year. Pretend a decomposed body of a murdered person is discovered buried in an area with no trees. Pollen is discovered on a piece of the victim’s clothing.
1st – Observe the shape of the pollen grains.
2nd – Identify the kind of plant the pollen grains came from (pretend you identify
them as Oak Tree pollen.
3rd – The victim was most likely murdered in an Oak Forest in the SPRING (when
Oak Trees typically bloom).
*The study of pollen is called PALYNOLOGY and the use of pollen to help solve crimes is FORENSIC PALYNOLOGY.
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Procedures:
Part 1 – Flower Dissection
1. Pick up a dissecting needle, dissecting scissors, a pair of forceps, a scalpel, a microscope slide and cover slip, a stereomicroscope (dissecting microscope), and a compound
microscope.
2. Use a flower supplied by your supervisor, or the flower you brought with you. Record, in Table 1, the KIND OF FLOWER you are observing. Use the stereomicroscope at any time to get a better view of your flower and its parts.
3. The flower you are observing is a plant’s reproductive structure. Most people think about a living organism being either a male or a female, however, the majority of the flowers you are familiar with are both male and female (and contain BOTH male and female reproductive organs).
4. A flower is composed of several important parts that are usually arranged in whorls (arranged in a circle that goes around the flower). These parts are attached to the base of the flower – an area called the RECEPTACLE.
5. Let’s start at the bottom of the flower and work our way up and toward the inside. The bottom of the flower is usually composed of a leaf-like whorl called the CALYX. The calyx can be green, brown, or can even be the same color as the flower’s petals (which might make it difficult to identify). Each individual, leaf-like part of the Calyx is called a SEPAL. A Calyx is usually composed of several sepals, but in some flowers there may only be a single sepal (different kinds of flowers have different numbers of sepals). The Calyx surrounds and protects the flower before it opens.
Record the following Calyx/Sepal information in Table 1: What is the color of your flower’s Calyx?
How many total Sepals are present on your flower?
6. Located above the Calyx is another whorl called the COROLLA. The Corolla is composed of individual PETALS that are usually brightly colored (this is the part of a flower you are probably most familiar with). The Petals are colored to help attract pollinators (like insects and birds). Some plants have odd-shaped Petals that form tubes, trumpets, and hoods. Some Petals also contain oils that give the flower its scent (to help attract pollinators). Some petals also contain special glands (usually near their base) that produce sweet tasting nectar (to help attract pollinators).
Record the following Corolla/Petal information in Table 1:
Describe the color or combination of colors of your flower’s Corolla.
How many total Petals are present in your flower (including any unusual petals)? Does your flower have a distinctive scent? If yes, do you like the scent?
7. Look inside the Corolla of your flower and you should see the reproductive structures. The male structures usually form a whorl around the single female structure, which is usually in the center. Use scissors to remove the Sepals and Petals of your flower so you will have a better view of the reproductive structures.
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8. Locate the whorl of male reproductive structures (each has a thin stalk with an enlarged, club-like end). Each stalk and club-like end is called a STAMEN. The stalk is called a FILAMENT and the enlarged, club-like end is the ANTHER.
Record the following Stamen information in Table 1: How many Stamen does your flower have?
9. Remove one of the Stamens and look at it under the stereomicroscope. The Anther is where POLLEN is produced. Pollen are male reproductive cells (like sperm in
animals). The pollen cells are produced in pollen sacs found within the Anther. If the Anther is mature you should be able to see the very small Pollen cells (sometimes called pollen grains). The pollen will probably resemble a very fine powder.
10. Tap the Anther on a microscope slide to collect some pollen, add a drop of water, and cover with a cover slip (if you are having trouble getting pollen you can also place a piece of the Anther on the slide, add water, cover with a cover slip, and squash the Anther to release some pollen). Observe the pollen with a compound microscope. Remember, Pollen grains from different plants have different shapes. Some pollen are round, some have rounded bumps, some are more triangular-shaped, some have small hooks, some have clear areas on their insides, etc.. View with HIGH POWER and make a NEAT and ACCURATE sketch of the pollen grains from your flower in Table 1.
11. The last part if the flower to observe is the female reproductive structure. This
structure is usually located in the very center of the flower and appears as a stalk rising up in the middle of the Stamens. The entire female structure is called the PISTIL. The Pistil is composed of a stalk, called the STYLE, and an enlarged end at the top of the stalk, called the STIGMA, that may be split into several sections. The Stigma is often sticky – try touching it! You should also notice a swelling at the base of the Pistil (near the receptacle area). This is the OVARY. The Ovary is where the eggs are produced – and where the seeds (the babies) develop once the eggs are fertilized.
12. Determine if the Ovary is located Above The Receptacle (the ovary is above the petals), Below The Receptacle (the ovary is below the petals), or Within The Receptacle (the petals are attached to the sides of the ovary). Record the Ovary’s location (using one of the above descriptions) in Table 1.
13. The inside of the Ovary is usually divided into several, room-like spaces called LOCULES. Each Locule is filled with OVULES – the round,
developing eggs that will someday become the seeds. Different kinds of plants have different numbers of Locules with different numbers of Ovules. Use a scalpel to cut off the Pistil and a small portion of the upper Ovary (see the sketch at right). Look down on the cut section of the Ovary (use the stereomicroscope if needed) to determine how many Locules your ovary contains (see sketch at right).
this ovary contains 3 Locules – each filled with ovaries
1 2
3
side view
top view
cut ovary here
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14. Use a scalpel and cut the ovary in half lengthwise (see sketch at right). Count how many Ovules are present in ONE Locule (use a
stereomicroscope for magnification).
Record the following information about your flower’s Ovary in Table 1: How many Locules does your flower’s Ovary contain?
How many Ovules are there in one Locule?
15. It all works together like this: Pollen grains carried by the wind or on an insect/bird pollinator get stuck on the sticky Stigma. The Pollen then grows a long tube all the way through the Style down to the Ovary. The Pollen then fertilizes an egg in the Ovary (releases its DNA into the egg). The fertilized egg then becomes a seed. The ovary often swells and grows to become a fruit (like an apple), which surrounds the seeds. 16. Clean up your lab station as you prepare for Part 2 of the Training Lab.
Part 2 – Observing Pollen From Different Plants
1. Pollen wouldn’t be a very useful forensic tool if all pollen looked the same. You are about to discover, however, that pollen comes in many shapes and sizes – and that it is possible to identify the source of the pollen (what kind of plant it came from) by observing a pollen’s unique size and shape.
PREPARING TO COLLECT WIND-BLOWN POLLEN FROM OUTSIDE
2. Pick up a clean, glass microscope slide and use a water-soluble marker to label one corner of the slide with your initials (or attach a label). Each person can make their own slide or you can make a single slide for your group.
3. Use your finger to place a thin layer of Vaseline/petroleum jelly on one side of the microscope slide (cover the middle third of the slide with Vaseline/petroleum jelly). 4. Place your microscope slide outside (Vaseline/petroleum jelly side UP) where it can sit undisturbed for 24 hours. Wind-blown pollen in the area will stick to your microscope slide. You will observe the pollen you collected tomorrow. Continue on with Step #5. OBSERVING POLLEN PHOTOGRAPHS
5. Pick up the “Pollen Reference Photographs – Pollen From Various Plants” from your Supervisor. These pages contain pictures of pollen taken from eight different plants. 6. Complete the following observations for all eight pollen samples shown in the “Pollen Reference Photographs”. Record your observations in Table 2.
A. RELATIVE SIZE OF THE POLLEN GRAIN – compare the sizes of the eight pollen grains (the pollen grain magnifications are visible on each picture). Record each pollen grain size as: SMALL, MEDIUM, or LARGE.
B. SHAPE OF THE POLLEN GRAIN – describe the shape of each pollen grain as: ROUND, OVAL, TRIANGULAR, or OTHER (if other, describe the pollen’s shape).
C. OUTER COVERING CHARACTERISTICS – pollen is composed of both an outer and inner covering. The outer covering often has special characteristics that can help you identify the pollen you are observing. Describe the outer covering characteristics