Presentation on theme: "Affordable Forensics Fun Jocelyn Koller University of Maryland Extension 4-H STEM Associate Agent The University of Maryland Extension programs are open."— Presentation transcript:
Affordable Forensics Fun Jocelyn Koller University of Maryland Extension 4-H STEM Associate Agent The University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, or national origin, marital status, genetic information, or political affiliation, or gender identity and expression.
Three affordable forensics lessons: 1.Fingerprints 2.Ink Chromatography 3.Toolmarks For each lesson, we will: Perform Hands-on Investigation Apply to Broader Scientific Topics Discuss Lab Safety
Fingerprints Why do we have fingerprints? There are three types of fingerprints: 1.Plastic- impression 2.Latent- invisible to the naked eye 3.Patent- visible prints
Plastic Fingerprints Definition: Fingerprints that leave ridge impressions in a substance, i.e. mud, clay Plastic Fingerprint Exercise Materials needed: Play dough Directions: Ask youth to press into the play dough and view the ridge impressions. Use a magnifying glass, if needed.
Latent Fingerprints Definition: Fingerprints that are invisible to the naked eye. Latent Fingerprint Exercise Materials needed: Magnifying glass, or smooth glass/plastic like surface Directions: Ask youth to rub fingers through their hair to pick up oils. Then place a fingerprint on the magnifying glass and view. Use another magnifying glass, if needed.
Patent Fingerprints Definition: Fingerprints that are visible to the naked eye. Patent Fingerprint Exercise Materials needed: Magnifying glass, ink pad, FBI Applicant fingerprint card, Ink remover wipes, Loop, Whorl, Arch cards, Pen/Pencil Directions: Ask youth to complete the FBI Applicant fingerprint card. Then, ask youth to fold the card at the line under right and left fingerprints. Roll fingerprints in ink pad to obtain a full print. The roll the finger in the corresponding box.
Patent Fingerprints Patent Fingerprint Exercise Continued Directions: Ask youth to use a magnifying glass and the loop, whorl, and arch cards to identify his/her fingerprint patterns. Write L, W, or A in the boxes to identify the prints.
Patent Fingerprints Patent Fingerprint Exercise Continued Image taken from:
Ink Chromatography Adapted from: Introduction: Ink chromatography allows us to separate and analyze the colored pigments that make up markers. Even though a marker writes in only one color, there may be hidden pigments in the marker that you cannot see. Ink chromatography will allow you to see all pigments inside of a marker by creating a chromatogram. Ink Chromatography Materials needed: Coffee filter, Black Marker (variety of brands), Scissors, Plastic Cup, Wooden coffee stirrer, Alcohol, Pencil, Note written in black marker, Ruler, Calculator Lab Safety: 1.Wear safety goggles 2.Alcohol is flammable. Store accordingly.
Ink Chromatography Procedure: 1.Cut a 1’’ strip of paper from the coffee filter. 2.Cut the end of the strip so it makes a ‘V’. 3.Choose a marker to test. Record the marker brand name: ______________________________________ 4.Using the marker, draw a line from one side of the strip of paper to other. 5.Pour about 1’’ of alcohol into a plastic cup. 6.Place the pointed end of the strip of paper into the alcohol, but make sure the marker line stays above the alcohol. 7.Put a wooden coffee stirrer through the top of the strip to hold the chromatogram in place. 8.The alcohol will begin moving up the strip and will carry with it the ink pigments. 9.Wait about 10 minutes for your chromatogram to develop.
Toolmarks Adapted from: Introduction: When two objects come in contact with each other, the harder object will leave an impression in the softer such as in the case of toolmarks. Toolmark analysis is used to compare tools to toolmarks found at the crime scene. Toolmark Analysis Materials needed: Variety of tools, clay, card stock, ruler, magnifying glass, pen/pencil Lab Safety: 1.Wear safety goggles. 2.Choose youth-appropriate tools 3.Remind youth how to exchange tools
Toolmarks Tool Number Tool Name Drawing of Tool Width of Tip (mm) Length of Tip (mm) ObservationsMarking in Clay Directions: Complete Investigation 1 by filling out the chart, then match the toolmarks in Investigation 2.
Toolmarks Analysis Questions: 1.How might the marks of a new tool differ from a used tool? 2.How could one screwdriver produce two very distinct markings? 3.Do you think the markings of two identical tools (new and from the same manufacturer) would leave identical markings?
Ink Chromatography- Continued Procedure Continued: 10.When the alcohol has finished moving up the strip of paper, remove the paper from the cup and place it on a paper towel. 11.Each brand of marker produces a different combination of color pigments. 12.View the chromatogram, record how many different colors are present :___________ 13.Record the colors in the chart below. 14.Now, you will calculate the retention factor (Rf) of each color pigment. 15.Measure in millimeters from the original marker line to the farthest line where the alcohol traveled. Record this measurement in third column of your chart. 16.Calculate the same measurement for each color pigment on your chromatogram in the chart below. 17.To determine the Rf value for each pigment use this formula: Rf value= Distance traveled by color pigment/Distance traveled by alcohol 10.Record the Rf values for each color pigment.
Ink Chromatography Ink Chromatography Continued Analysis: 1.A solvent dissolves a substance, and a solute is the dissolved substance. Based on these definitions, what are the solvent and solute in this lab? 2.Which marker matched the note? How do you know? Is this enough to link a suspect to the note? ColorColor- Millimeters traveledAlcohol- Millimeters traveledRf value
Broader Scientific Applications Ink Chromatography Chemistry- Solutes and Solvents Measuring- Millimeters/Using a ruler
Conclusion There are affordable, low-tech forensics hands-on labs. Remember to focus on the science and evidence, not the crime Choose age appropriate scenarios, such as stolen lunch money, or a book bag taken from a locker. Remember lab safety! Use forensics to make broader scientific applications and to increase knowledge of basic science lab skills.