Elitch Gardensand

Forensic Science WorkbookMad Science Whodunnit Challenge

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Whodunnit Challenge

Forensic science is the use of the scientific method to gather and interpret evidence in a crime, with the intent to present the evidence in a court case. Forensics utilizes a number of scientific disciplines, including biology, chemistry, entomology, geology, and physics. It is the job of crime scene analysts to work together with law enforcement to determine what pieces of evidence are important to the crime and piece together what happened.

Each Mad Science station will give you an opportunity to look at and analyze the clues found at the scene using:

Fingerprint AnalysisSoil AnalysisFiber AnalysisForensic Chemical Analysis

It will be up to you to determine what evidence is relevant to the crime, find out what happened, and which of the suspects committed the crime! Once you have made your guess, the Mad Scientist at theChemical Analysis station can tell you whether you've found the correct perpetrator!

Each station will also provide information to answer the questions on the last page of your workbook. Once you have completed the challenge, return the completed page to any Mad Scientist to enter yourclass in a drawing to win a Mad Science party.

Whodunnit ChallengeThe CrimeSometime in the evening of May 18th, Fanny's Funnel Cakes concession stand near the Sea Dragon ride at Elitch Gardens was broken into. The perpetrator destroyed the stand's entire stock of funnel cake batter, amounting to several hundred dollars worth of ingredients, including flour, sugar, and vanilla extract. Several suspects have been identified based on motive and/or opportunity and park management has provided information on each suspect.

The Crime SceneThe crime took place in the Fanny's Funnel Cakes concession stand. The entire stock of funnel cake batter was dumped into the stand's trash cans. A crime scene unit processed the scene and found the following potential clues: fingerprints on the door, counter tops, trash cans, and batter storage containers; dirty footprints on the floor of the room; a torn blue fiber caught in the doorway; smudges of white powder on the countertops.

The SuspectsSuspect #1 works nights at the park as a Park Services employee, cleaning the park. Suspect found the door to the Fanny's Funnel Cakes employee entrance unlocked and ajar. Subject entered the concession stand, saw the ruined funnel cake batter, and called the Park Manager, who notified law enforcement.Possible Motive: recently applied for a day position in the park; was passed over for job.Opportunity: works nights at the park; has keys to all park venues.Alibi: arrived at park at 11 pm for shift, cleaning the park until crime scene found at 2:14 am.

Suspect #2 works at the Fanny's Funnel Cakes concession stand during the day. Suspect worked a short shift at the stand the day before, preparing funnel cake batter for use in the following days. Clocked out of the park at 4:03 pm.Possible Motive: overheard by coworker saying “tired of spending my days smelling like fried food”.Opportunity: working alone in the concession stand from 2:00 pm until 4:03 pm.Alibi: after leaving work, Suspect went home and spent night on the couch, binge watching Game of Thrones alone.

Suspect #3 worked at various concession stands in the park until he was fired by Park Manager one week ago. According to Park Manager, suspect was fired for repetitive lateness, as well as several complaints made about him from customers. Has been asked on three occasions to return park employee shirt to the park to HR office; as of last night, has not returned shirt.Possible Motive: angry at Park for being firedOpportunity: unsureAlibi: was at an event at the Pepsi Center with friends from 6pm until 11:30.

Suspect #4 is the representative for the popcorn company that supplies popcorn for Elitch Gardens.Possible Motive: Trying to boost sagging popcorn sales at park.Opportunity: unsureAlibi: was at a business dinner with manager of local movie theater, trying to convince theater to sell more popcorn.

Suspect #5 is one of the pretzel bakers at the park. Suspect works nights preparing dough and

shaping pretzels that will be baked the next day.Possible Motive: Trying to boost pretzel sales at the park.Opportunity: Works evenings at the park.Alibi: Making pretzels from 8:00 pm until 12:00 am, then went home.

Fingerprint Analysis

Everyday, we leave fingerprints on everything we touch. Each individual's fingerprint is unique; even identical twins have different fingerprints. These unique prints can be used in identification, for background checks, biometric security, and criminal investigations.

When a person touches an object, the oils on their fingers stay on the object, leaving behind an impression of the person's fingerprint. If there is dirt or other visible particles on the person's finger, theprint may be easy to see. If the person's hands are clean, tools can be used to create a visible fingerprint. Dark powder can be brushed over the fingerprint and will stick to the areas of oil, creating avisible print. The print can then be photographed or lifted using adhesive.

Each fingerprint is made up of ridges, or raised areas, and furrows, recessed areas. These ridges and furrows create the patterns of fingerprints; the oils from the ridges of a print are what sticks to an object and is left behind. Fingerprint patterns come in three basic types: loops, whorls, and arches.

Fingerprint identification also requires known fingerprints to compare the found print to. Fingerprint samples can be taken, and compared to a found print to determine who the print belongs to. Fingerprint identification also requires the discovery of an unsmudged print; if a print has been smudged or disturbed in any way, it can be difficult to compare it to another print.

Fingerprinting is one of the oldest examples of forensic science and has been used for more than 100 years!

Soil Analysis

Soil analysis is the use of soil science to aid in criminal investigations.

Similar to fingerprints, soils from different areas have different characteristics. If a sample of soil taken as evidence from a crime scene can be matched to a specific place, that can give investigators an idea of where the suspect was before the crime was committed.

Soil analysts look at several identifying characteristics, including sediment, color and soil structure.

Sediment refers to the rock particles that make up the majority of the soil. Analysts look at rock type, particle size, and weathering to determine where the soil may have come from.

Color can be indicative of the type of minerals or compounds found in the soil. Light gray or whitish soil may indicate the presence of lime (calcium oxide or calcium hydroxide). Darker brown or black soiloften contains organic material, while red, brown, or yellow soil indicates high amounts of iron.

Soil Structure refers to other physical characteristics of the soil, including sediment size, which determines whether the soil is sandy, silty, or clay-like; moisture content; and how the soil clumps.

Individually, these characteristics may not tell scientists much, but when put together, they often createa distinct picture of where the soil came from. Additionally, if soil from a crime scene can be matched to a suspect’s shoe, that provides evidence linking the suspect to the scene of the crime.

Fiber Analysis

The clothing we wear and the fabrics we use are made of many different materials. These materials are made of a number of different fibers; including man made, animal, and plant-based. Plant based fibers include cotton and linen; animal based fibers include silk and wool. Man-made fibers are numerous and include nylon, rayon, polyester, and acrylic.

When a piece of clothing or material catches on something, it may pull a piece of the fiber or material off. Fibers found at a crime scene may be used to link a person to the scene; however, in most cases, fiber evidence alone is not enough to confirm a suspect’s involvement in the crime. Additionally, fibers must be matched to a source material in order to be of much use. Fiber evidence is generally used in combination with additional evidence found at the scene.

The simplest way of comparing fibers for identification is to observe the individual fibers under magnification. This can often tell us if a fiber is natural or man-made, as man-made fibers are generally smoother than naturally occurring ones. Natural fibers are often shorter and have been woven or twisted together to create longer strands. Chemical tests can also help narrow down the source of the fiber; man-made fibers will generally melt more quickly than natural ones, and animal based fibers will dissolve in bleach while plant based and man-made fibers will not.

Individual fibers from cotton, wool, and rayon at 40x magnification

These analyses are helpful in determining in the source of the fibers, but may not aid in the investigation of the crime unless the fibers can be directly linked to the suspect. If investigators can prove that a fiber found at the crime scene likely came from a tear in the suspect’s jacket, that provides strong evidence the suspect was at the scene.

Chemical Analysis

Chemistry plays a vital part in forensics, allowing for the identification of unknown substances.

Most chemical identification today is performed using instruments, including a gas chromatograph andmass spectrometer. These instruments break up unknown substances into smaller identifiable molecules and arrange them on the instrument display, to create a pattern unique to that substance. The patterns of unknown substances can be compared to patterns of known substances (known as reference samples) to find a match.

GC-MS results for the molecule CH2CH3

Simpler chemical analyses can be performed in the field without the use of instruments. Knowing how certain substances react when treated with a certain chemical can allow us to identify unknowns by observing the reactions.

We will be comparing a number of known chemical reactions to the reaction of our unknown powder found at the scene to determine what the powder is.

Complete these questions and the form below and turn in the form to any Mad Scientist at the park.

1. What substance on people’s fingers allows a fingerprint to be transferred to an object?

2. How does chemical analysis allow investigators to identify an unknown substance?

3. Based on a soil analysis, you would expect the rocks at Red Rocks to be high in what mineral?

4. How can you tell man-made fibers from naturally occurring fibers?

5. After observing the clues at each station, which suspect do you think is the perpetrator?

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Additional Questions

1. After visiting the fingerprint station, who should be included in your list of potential suspects?

2. What sort of fibers were found at the crime scene? Can they be linked to any of the suspects?

3. What did the soil analysis tell you about where the suspect might have been before committing the crime?

4. After performing the chemical analysis, what was the powder found at the crime scene? Where might it have come from?

5. If a person's fingerprints are found at the scene of a crime, should they automatically be included in the suspect list? Why or why not?

6. Why would it be preferable to perform a chemical analysis in a laboratory rather than in the field?

7. What are the limits in using soil and fiber analyses to find a suspect? Would a single soil or fiber analysis provide enough evidence to convict someone of a crime?