n/a MYSTERY OF THE BLOOD STAIN (RE)

Transcription

1 DATA SHEET Order code Manufacturer code Description n/a MYSTERY OF THE BLOOD STAIN (RE) The enclosed information is believed to be correct, Information may change without notice due to product improvement. Users should ensure that the product is suitable for their use. E. & O. E. Page 1 of 11 Revision A 20/02/2007 Sales: Technical: Fax: Sales@rapidelec.co.uk Tech@rapidelec.co.uk

2 Neo/SCI Teacher s Guide The Mystery of the Bloody Stain using Neo/BLOOD # Objectives Perform a simple test to identify if a red stain is simulated blood Determine the ABO and Rh blood type of unknown simulated blood samples Identify which of the three suspects is most likely to have committed the crime Determine the probability that the same blood type as the suspect's is found in the general population 1 For complete technical support call Neo/SCI TM PO Box Rochester, NY support@neosci.com Copyright Neo/SCI. All Rights Reserved.

3 ABO and Rh blood type system MNS blood type system Red and white blood cells Hemoglobin Hematocrit Platelets Antibodies Antigens Serum Science Concepts Safety & Disposal The simulated Neo/BLOOD and sera samples provided in this kit contain no biological components and are therefore safe from any potential biological hazards. However, students should always wear safety goggles, gloves and a lab apron to protect the eyes and clothing when working with any chemicals. The dye in the simulated Neo/BLOOD solution will stain your skin and clothing. Be sure that students wash their hands before leaving the laboratory. Crime Scenario A team of crime investigators were called to the scene of a burglary. Late last night someone broke into a jewelry store. Upon arrival, the crime investigators noticed that several of the glass display cases were smashed, scattering glass throughout the store. A closer investigation of the glass fragments revealed that small pieces of what appeared to be blood-stained clothing were left behind. The pieces of the clothing material were carefully collected and sent to the forensic lab for analysis. After the crime investigators carefully reviewed all of the available evidence, they apprehended three suspects. Since select red-colored stains may look like blood, forensic scientists first need to determine if the red stain found at a crime scene is actual blood. A test is performed to confirm the presence of one of blood s components, such as hemoglobin. If the stain is indeed blood, it is then collected and taken to the forensic lab for further testing, such as blood typing. Your job as a forensic scientist is to provide crime investigators with additional proof in order to determine which of the suspects may have committed the burglary. You will first perform a test to verify that the stain is indeed blood and then type the blood sample found at the crime scene to match its type with the blood samples drawn from 3 suspects. Any simulated Neo/BLOOD waste from this lab may be disposed of by pouring it down the drain with copious amounts of water. 2

4 Kit Materials List Pre-lab Setup 30mL Anti-A Simulated Serum 30mL Anti-B Simulated Serum 30mL Anti-Rh Simulated Serum 40 Blood typing trays Cheese cloth 25mL Crime Scene Simulated Neo/BLOOD sample 25mL Suspect #1 Simulated Neo/BLOOD sample 25mL Suspect #2 Simulated Neo/BLOOD sample 25mL Suspect #3 Simulated Neo/BLOOD sample 40 Stirring sticks, blue 40 Stirring sticks, yellow 40 Stirring sticks, green Materials Needed But Not Provided: Compound microscope Coverslips Food dye, red Microscope slides Paper towels Cut the cheese cloth provided into 2" x 2" squares - one for each of your students. Lay the squares on a paper towel and apply 2-3 drops of the simulated blood onto each of them. Remember that the simulated blood provided has simulated blood cells which is what students will look for in their presumptive test for blood in Activity 1. You may want to stain some of the squares with dilute red food color which does not contain any simulated blood cells for comparison. Allow the squares to air dry and then pass them out to each of your students. Enough materials are provided for up to 40 students to type all four unknown simulated Neo/BLOOD samples provided in the kit. Provide each student with one blood typing tray and a set of blue, yellow and green stirring sticks. Set up a lab station with the simulated Neo/BLOOD samples and the simulated blood typing sera for students to dispense the samples onto their trays. Alternatively, the samples may be circulated until every student types all four simulated blood samples. Time Requirements Pre-lab preparation 5 minutes Lab Activity 1 15 minutes Lab Activity 2 30 minutes 3 The Mystery of the Bloody Stain using Neo/BLOOD #

5 Lab Activity Procedures & Notes Activity 1 Presumptive Test for Blood One of the preliminary tests that crime investigators perform at the scene of a crime is to determine whether or not a suspicious red stain is blood. Since the blood you ll be using is simulated, it does not contain hemoglobin, the presence of which confirms that the stain is actual blood. Instead, you ll look for the actual presence of simulated blood cells under a microscope. What to do... Step 1 Provide each student with a red-stained piece of cloth. Students should cut out a small portion of the stained cloth or remove individual fibers and place them flat on a microscope slide. What you need Per Student 1 Cloth, stained 1 Compound Microscope 1 Coverslip 1 Microscope slide Paper towels Water Step 2 Students should place a drop of water over the stained cloth and place a coverslip over it. 4

6 Step 3 Next, students should place the prepared slide under a microscope and examine it under 100X magnification. Have students scan the entire area of the stain and note the presence of any simulated blood cells, either attached to the fibers or nearby. Simulated red blood cells will appear pink, while white blood cells are stained blue. Questions 1. Did your stained cloth sample contain simulated blood cells? What does the presence of these simulated cells indicate? Results will vary based upon which sample students received. 2. Why does the presence of hemoglobin provide proof that a suspicious stain is actual blood? Hemoglobin is found in red blood cells. Therefore, if a suspicious stain contains hemoglobin, it is due to actual blood. Hemoglobin facilitates the transfer of oxygen to the body tissues and carbon dioxide to the lungs so that is can be excreted. 5 The Mystery of the Bloody Stain using Neo/BLOOD #

7 Lab Activity Procedures & Notes Activity 2 What to do... Step 1 Provide your students with simulated blood scene and suspect samples, along with the anti-sera. Students should place 5 drops of the Crime Scene Simulated Blood Sample in each well on their blood typing tray. ABO and Rh Blood Typing Once it is verified that the stain is indeed blood, it should then be carefully collected and taken to the forensics lab. The next test is to type the blood sample collected at the crime scene and compare it to the blood types of the three apprehended suspects. A What you need B Rh Per Student Anti-A Serum (simulated) Anti-B Serum (simulated) Anti-Rh Serum (simulated) 4 Blood samples (simulated): Crime Scene Suspect 1 Suspect 2 Suspect 3 1 Blood typing tray Paper towels 1 set Stirring sticks (blue, green and yellow) Step 2 Students place 3 drops of Anti-A Simulated Serum in Well A. Step 3 Students place 3 drops of Anti-B Simulated Serum in Well B. Step 4 Students place 3 drops of Anti-Rh Simulated Serum in Well Rh. 6

8 Step 5 Students should use a separate stirring stick to mix the simulated blood and serum in each well for approximately 10 seconds. Step 6 Have your students carefully examine each well to determine if the simulated blood sample in each well have clumped or agglutinated. Have them record their results and observations in Data Table 1. Step 7 Have the students thoroughly rinse the tray and stirring sticks and repeat Steps 1-6 to type the simulated blood samples of the three suspects. A B Rh 7 The Mystery of the Bloody Stain using Neo/BLOOD #

9 Understanding your results: Clumping indicates that the simulated blood sample contains antigens that reacted against the antibodies in the typing serum that the students mixed it with. Type A If the blood in Well A is the only blood that agglutinates or clumps, then the blood sample you tested is Type A blood. Type B If the blood in Well B is the only blood that agglutinates or clumps, then the blood sample you tested is Type B blood. Type AB If the blood in both Well A and Well B agglutinates or clumps, then the blood sample you tested is type AB blood. Type O If the blood in both Well A and Well B does not agglutinate or clump, then the blood sample you tested is Type O blood. Rh If the blood in Well Rh agglutinates or clumps, then the blood sample you tested is Rh Positive blood. Data Table 1 Simulated Blood Sample Agglutination in Well A (+/-) Agglutination in Well B (+/-) Agglutination in Well Rh (+/-) Blood Type Observations Crime Scene + + A+ Suspect AB+ Answers will vary. Students should describe the Suspect A+ agglutination reaction in each well. Suspect 3 + B 8

10 Questions 1. Based upon your results, which of the suspect s blood type matches the blood type found at the crime scene? The blood type of Suspect #2 matches the blood type found at the crime scene. 2. Based upon your blood typing results, do you think there is enough evidence to prove the suspect committed the burglary? No. Although blood and blood stains left behind in a crime scene are important evidence and provide crucial information in a criminal investigation, blood type evidence alone is only used to exclude someone as a suspect, thereby narrowing the list of possible suspects. The only other technique that could possibly provide more conclusive evidence about who actually committed the crime is DNA fingerprinting. 3. How is this simulated blood typing activity similar to actual human blood typing? The blood typing procedure for simulated blood is similar to actual blood typing. Simulated blood agglutinates in a similar fashion to actual blood when mixed with the appropriate antiserum. 4. Calculate the probability that a person would have blood that is types AB, N and Rh-. AB N Rh- 100 X 100 X 100 = (25) x (4.54) x (6.67) = 757 This means that 1 out of every 757 people in the US has blood types AB, N, Rh- blood. 9 The Mystery of the Bloody Stain using Neo/BLOOD #

11 Cross-Curricular Integration Technology Discuss with your students the various advances that are being made to develop artificial blood which would eliminate the need of human blood transfusion in emergency situations. Health Relate blood analysis to various health conditions which can be diagnosed based upon blood cell counts and morphology. Discuss with your students the various blood-borne pathogens that are carried in blood and the diseases that they cause. Social Studies Discuss with your students the process of blood donation and the crucial function that it serves in saving people s lives in a medical emergency. Discuss the facts and myths of blood donation. Mathematics Various math concepts can be incorporated in this investigation in which students determine the percent frequency of specific blood types in a given population. Assessment The questions included in the Questions section are provided as a means for you to assess your students understanding of the concepts and whether they can apply them to everyday situations. They should also their ability to think critically and visually. There are certain ideas that your students should be able to understand after completing this activity. They should be able to understand the ABO and Rh blood typing system, the blood typing procedure and interpret blood typing results. Students should also be able to understand and define terms such as antigens, antibodies, serum, red and white blood cells, hemoglobin, hematocrit and other terms presented in this investigation. Additionally, you can set up a teacher-designed laboratory practical examination which displays the lab setup and asks related questions. Students can be required to make an oral presentation to their class who would ask selected questions to evaluate student learning of blood typing and blood cell structure and function. Students can demonstrate their learning by conducting the activities in the Going Further section or by completing an Internet search and presentation of what they found. 10