Safety note

As with any hands-on activity, we recommend that you perform the activities yourself before involving your students and provide proper supervision of students during the lesson.

In cases where special safety instructions are not given, use common safety precautions, especially when working with hot, sharp, or breakable items. Be sure to read and follow warning labels on household chemicals.

Terrific Science makes no claims of the originality of the lessons. Neither Terrific Science nor the authors assume any liability or responsibility for the use of information disseminated through the Web Lesson Exchange, nor can it be assumed that all necessary warnings and precautionary measures are contained in these publications.

Lesson List

Bloodstain Pattern Simulations: A Physical Analysis
DNA Fingerprinting: The Great Cafeteria Caper
Drug Analysis Using Thin-Layer Chromatography
Fingerprinting Lab
Innocent or Guilty: A Lab on DNA Gel Electrophoresis
Spectroscopy as a Tool for Forensic Chemists
Using Blood-Typing to Determine Causes of Death in Surgery Patients
Using Plant Pigments to Link a Suspect to a Crime

Lesson Descriptions

Bloodstain Pattern Simulations: A Physical Analysis

Following graphical and vector analysis, this lab exercise is an open-ended or discovery activity. Students receive bloodstain pattern evidence from a crime scene. They must then answer a series of questions through inquiry, observation, measurement, and analysis. To complete this challenge, students reconstruct the evidence through four standard models to derive qualitative characteristics and quantitative relationships that address the evidence at the crime scene. In addition, students will utilize the following impact equation and the concept of free fall in which an object falls from rest.

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DNA Fingerprinting: The Great Cafeteria Caper

Students will extract DNA from their own hair roots.A DNA fingerprinting simulation kit with standard DNA samples will also be used in this experiment.The DNA will be digested with a variety of restriction enzymes (e.g.,B am H I and Hin d III).Students will run an electrophoresis gel to examine patterns of their DNA along with standard DNA.The experiment will be based on a crime scene scenario.

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Drug Analysis Using Thin-Layer Chromatography

The majority of evidence submitted to crime labs comes from drug-related crimes. Often, this evidence includes unidentified powders that may be illegal drugs. In order to prosecute individuals for possession of illegal substances, it is necessary for forensic scientists to positively identify any suspected drugs submitted to the laboratory. In addition, forensic toxicologists must determine the identity of drugs found in the bodies of drug-overdose victims. Although illegal substances can cause overdose, people also overdose on common over-the-counter (OTC) drugs, like aspirin, when attempting to take their own lives. Thin-layer chromatography (TLC) is one technique used to identify unknown drugs. Chromatography is simple to perform, is straightforward to interpret, and works equally well for legal and illegal substances. This experiment uses TLC to identify the active ingredients in some common OTC painkillers.

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Fingerprinting Lab

After a lecture/discussion on fingerprinting techniques, students recover latent prints by iodine fuming, cyanoacrylate fuming, and dusting with powder.Each student will provide a fingerprint for identification by another student. A database of fingerprints of the class will be made to help in the identification of the unknown print.

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Innocent or Guilty: A Lab on DNA Gel Electrophoresis

This lesson, based on EDVOTEK Kit #109, “DNA Fingerprinting I: Identification of DNA by Restriction Fragmentation Patterns,” presents a simulation of a DNA fingerprint (RFLP—Restriction Fragment Length Polymorphism). The prelab section introduces the importance of DNA fingerprinting—a form of identification that is being accepted by both scientific and legal experts. The procedure is used in forensic work, paternity suits, missing-person cases, archeology, and animal breeding. The protocol for the lab is introduced. The lab involves students preparing a gel for electrophoresis. DNA fragments, which have been predigested using two different restriction enzymes, will be run on a gel electrophoresis apparatus, and the results will be analyzed to determine which suspect committed the crime. The post-lab section concentrates on the ethical implications of DNA fingerprinting.

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Spectroscopy as a Tool for Forensic Chemists

This hands-on unit will introduce students to atomic emission and absorption spectra. Chemistry students will “fingerprint” some elements and identify them in some common sources. They will then create spreadsheets to relate the Bohr model of the atom to the observed spectral lines of the hydrogen atom. Raman spectra are used to solve a forensic case study. Finally, students will examine a commercial application of photochemistry called the cyanotype process. This unit will strengthen the students’ organizational and analytical thinking skills through the creation of spreadsheets and will involve the students in some practical applications of quantum chemistry.

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Using Blood-Typing to Determine Causes of Death in Surgery Patients

In this activity, students will determine whether a higher-than-normal death rate among surgery patients in a hospital was caused by faulty blood-typing. They will be given a sheet that contains the blood types on record for the patients, the type of blood each patient received, and whether or not each survived the surgery. The students will be provided with simulated samples of each patient’s blood and of the blood provided to each patient during surgery and a blood-typing kit. Students will use the information and materials to determine correct blood types for each patient and bag. They will also be able to determine whether patients were given the correct type of blood or not.

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Using Plant Pigments to Link a Suspect to a Crime

Students will use chromatography to separate plant pigments collected from a fictitious crime scene and suspects. Students will then compare the R f values of the plant pigments to determine whether the plant pigments found on any of the suspects match the plant pigments found at the crime scene. Matching plant pigments would be one piece of evidence linking the suspect to the crime scene.

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