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Unit 3 Fundamental Laboratory Skills. Students will explore essential laboratory safety skills and fundamental skills related to microscopy and measurement. Reasons for Proper Lab Safety.

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unit 3 fundamental laboratory skills

Unit 3 Fundamental Laboratory Skills

Students will explore essential laboratory safety skills and fundamental skills related to microscopy and measurement.

reasons for proper lab safety
Reasons for Proper Lab Safety

https://ssl.perfora.net/s218423312.oneandoneshop.com/sess/utn;jsessionid=154c89455964664/shopdata/0105_Posters/product_overview.shopscript

In January 2010 there was a lab accident at Texas Tech with a student (Brown). The brief description of the student's accident [Brown] is impressive:

'When Brown thought he was done, he set down the mortar and took off his goggles.  Then he decided to give the compound one last stir.  The mortar exploded in Brown's hands.  Brown "lost three digits on his left hand, severely lacerated his right hand, perforated his left eye, scratched his right eye and had superficial cuts to the parts of his body that were exposed," says an investigation report...' (Chemical and Engineering News, Aug 23, 2010, pp. 34-35.)

http://pubs.acs.org/cen/science/88/8834sci1.html

demonstrate proper donning and removal of personal protective equipment
Demonstrate proper donning and removal of Personal Protective Equipment.
  • A. Proper donning (from CDC website)
    • 1. The type of PPE used will vary based on the level of precautions required.
    • 2. Keep hands away from face. Limit surfaces touched. Change gloves when torn or heavily contaminated. Perform hand hygiene.
    • 3. GOWN: Fully cover torso from neck to knees, arms to end of wrists, and wrap around the back. Fasten in back of neck and waist
    • 4. MASK OR RESPIRATOR: Secure ties or elastic bands at middle of head and neck. Fit flexible band to nose bridge. Fit snug to face and below chin. Fit-check respirator.
    • 5. GOGGLES OR FACE SHIELD: Place over face and eyes and adjust to fit.
    • 6. GLOVES: Extend to cover wrist of isolation gown.
proper removal of ppe from cdc website
Proper removal of PPE (from CDC website)

1.Except for respirator, remove PPE at doorway or in anteroom. Remove respirator after leaving room and closing door.

2. GLOVES: Outside of gloves is contaminated! Grasp outside of glove with opposite gloved hand; peel off. Hold removed glove in gloved hand. Slide fingers of ungloved hand under remaining glove at wrist. Peel glove off over first glove. Discard gloves in waste container.

3. GOGGLES OR FACE SHIELD: Outside of goggles or face shield is contaminated! To remove, handle by head band or ear pieces. Place in designated receptacle for reprocessing or in waste container.

4. GOWN: Gown front and sleeves are contaminated! Unfasten ties. Pull away from neck and shoulders, touching inside of gown only. Turn gown inside out. Fold or roll into a bundle and discard.

5. MASK OR RESPIRATOR: Front of mask/respirator is contaminated — DO NOT TOUCH! Grasp bottom, then top ties or elastics and remove. Discard in waste container.

washing hands
Washing hands!

Apply a small amount of powder to hands.

Wash in your usual method.

Evaluate your current method

demonstrate cdc requirements for hand washing
Demonstrate CDC requirements for hand washing
  • A. Hand washing is the single most important prevention step for reducing disease transmission
    • 1. Wet hands with running water; place soap in palms; rub together to make a lather; scrub hands vigorously for 20 seconds; rinse soap off hands.
    • 2. If possible, turn off the faucet by using a disposable paper towel.
    • 3. Dry hands with a disposable paper towel. Do not dry hands on clothing.
washing hands1
Washing hands!

Apply a small amount of powder to hands.

Wash in your new method.

Evaluate your new method

slide8

B. Hand-Washing Agents

    • 1. Liquid soap dispensed by a hand or foot pump is recommended.
    • 2. Alcohol-based hand sanitizers can be used if soap and water cannot be made available and are effective against multiple common disease agents (e.g., shiga toxin-producing E. coli, Salmonella, and Campylobacter). However, they are ineffective against certain organisms (e.g., bacterial spores, Cryptosporidium, and certain viruses).
    • 3. The U.S. Food and Drug Administration recommends using an alcohol-based hand sanitizer with a concentration of 60% or higher to be effective against common disease agents.
    • 4. Hand sanitizers are less effective if hands are visibly soiled. Therefore, visible contamination and dirt should be removed to the extent possible before using hand sanitizers.
identify biohazards and perform biohazard safety procedures
Identify biohazards and perform biohazard safety procedures
  • A. Biohazard: (from American Heritage Dictionary) A biological agent, such as an infectious microorganism, or a condition that constitutes a threat to humans, especially in biological research or experimentation. The potential danger, risk, or harm from exposure to such an agent of condition.
    • 1. Examples include airborne diseases such as Ebola, resin gas, etc; blood pathogens, body fluid transmittable diseases like HIV, hepatitis, etc. and any material these body fluids could be found on.
    • 2. Known as blood-borne pathogens (BBPs) and other potentially infectious materials (OPIM).
identify biohazards and perform biohazard safety procedures1
Identify biohazards and perform biohazard safety procedures
  • B. Biohazard safety procedures (from www.clinimmune.com/documents/BiohazardTrainingEMS3-07.ppt)
    • 1. The Universal Precaution Rule: Treat all human blood, bodily fluids and other potentially infectious materials as if they are infectious.
    • 2. Exposure Controls consist of those policies and practices that prevent occupational exposures to infectious materials, including:
      • a. Administrative Controls
        • Exposure control plan (ECP)
        • Individual Laboratory Risk assessments
        • Universal (Standard) Precautions
        • Personal Protective Equipment (PPE)
        • Engineering Controls (HVAC, bio-safety cabinets, self-sheathing needles, safer medical devices, and  needleless systems)
slide11

3. Sharps Precautions

      • You must exercise care when using needles, scalpels, glass pipettes and other sharp instruments or devices.   Follow these rules of thumb when handling sharps:
        • Do not recap, bend, break, or otherwise manipulate used needles by hand.
        • Do not remove used needles from disposable syringes.
        • Place used sharps in labeled or color-coded puncture-resistant, leak-proof, closable, sharps containers for disposal.
        • Do not overfill sharps containers.
        • Consider the use of alternative, non-sharps equipment whenever possible.
slide12

4. Personal Protective Equipment (PPE)

      • Whenever you may be exposed to infectious materials you must wear the appropriate personal protective equipment. PPE places a barrier between you and potentially infectious material.
  • Here are some basic rules to follow:
        • PPE should be readily accessible
        • Always wear PPE in exposure situations-Wear a lab coat, gloves and eye protection whenever splashing is imminent
        • Remove and replace PPE that is torn or punctured, or that loses its ability to function as a barrier to potentially infectious materials
        • Remove PPE before leaving the work area
        • Dispose of contaminated PPE properly-in biohazard containers
slide13

5. Hand Hygiene

  • a. Most common mode of transmission of pathogens is via hands!
  • b. Often infections acquired in healthcare and research settings are due to not washing your hands.
  • c. Employees must wash their hands with soap and water:
        • immediately, or as soon as feasible, after removal of gloves or other PPE.
        • whenever they leave the work area, go on break, or before eating.
        • following contact with blood or other potentially infectious materials.
slide14

6. Engineering controls

    • a. Containment is the concept of managing materials to reduce or eliminate potential exposures to personnel, the general public and the outside environment.
locate and identify chemicals using msds sheets
Locate and identify chemicals using MSDS sheets.
  • What are MSDS sheets
    • The MSDS is a detailed informational document prepared by the manufacturer or importer of a hazardous chemical.  It describes the physical and chemical properties of the product. MSDS’s contain useful information such as flash point, toxicity, procedures for spills and leaks, and storage guidelines.
slide16
MSDS
  • Information included in a Material Safety Data Sheet aids in the selection of safe products, helps you understand the potential health and physical hazards of a chemical and describes how to respond effectively to exposure situations. Although there is an effort currently underway to standardizes MSDS’s the quality of individual MSDS’s vary. A MSDS may be useful but it can not substitute for prudent practices and comprehensive risk management.
slide17
MSDS
  • They must be written in English and contain:
    • The name of the chemical (same as on the label)
    • The chemical and common names of the substance
    • A lsiting of the ingredients
    • A statement of the ingredients tha tare known carninogens or that present other known hazards
    • Any specific hazards
slide18
MSDS
  • The information of greatest concern to workers is featured at the beginning of the data sheet, including information on chemical composition and first aid measures. More technical information that addresses topics such as the physical and chemical properties of the material and toxicological data appears later in the document.
msds sheet activity
MSDS Sheet Activity

Using two MSDS sheets, complete two worksheets filling in information found on the MSDS

slide20
MSDS
  • Sections & Terms used on MSDS sheets
    • Section 1. Chemical product and company identification
      • Links the MSDS to the material. Identifies the supplier of the MSDS. Identifies a source for more information. You must include the manufacturer’s name.
    • Section 2. Composition/information on ingredients
      • Lists the OSHA hazardous components May also list significant nonhazardous components. May also include additional information about components (e.g., exposure guidelines)
      • You can patent your product to protect the contents, but you must disclose all hazardous constituents.
slide21
MSDS
  • Section 3. Hazards identification, including emergency overview
    • Provides information on the potential adverse human health effects and symptoms that might result from reasonably foreseeable use and misuse of the material. May provide emergency overview.
    • Typically, this section is brief, one or two paragraphs.
  • Section 4. First aid measures
    • Provides instructions to be taken if accidental exposure requires immediate treatment. May also include instructions to medical professionals. This should include specific instructions to medical professionals; not general platitudes, like “seek medical help” or “apply CPR”
slide22
MSDS
  • Section 5. Fire fighting measures
    • Provides basic fire fighting guidance, including appropriate extinguishing media. Describes other fire and explosive properties useful for avoiding and fighting fires involving the material, such as flash point or explosive limits.
  • Section 6. Accidental release measures
    • Describes actions to be taken to minimize the adverse effects of an accidental spell, leak or release of the material.
  • Section 7. Handling and storage
    • Provides information on appropriate practices for safe handling and storage.
slide23
MSDS
  • Section 8. Exposure controls/personal protection
    • Provides information on practices, or equipment, or both, that are useful in minimizing worker exposure. May also include exposure guidelines. Provides guidance on personal protective equipment.
  • Section 9. Physical and chemical properties
    • Provides additional data that can be used to help characterize the material and design safe work practices.
  • Section 10. Stability and reactivity
    • Describes the conditions to be avoided or other materials that may cause a reaction that would change the intrinsic stability of the material.
  • Section 11. Toxicological information
    • May be used to provide background toxicological information on the material, its compounds, or both.
slide24

Section 12. Ecological information

    • May be used to provide information on the effects the material may have on plants or animals and on the material's environmental fate.
  • Section 13. Disposal considerations
    • May provide information that is useful in determining appropriate disposal measures.
  • Section 14. Transport information
    • May provide basic shipping classification information. [Comment: If any specific transportation label is required state it here. For bulk chemicals include the UN number. Otherwise just say "May be shipped normally as a nonhazardous matererial"
slide25
MSDS
    • Section 15. Regulatory information
      • May be used to proved any additional information on regulations affecting the material.
    • Section 16. Other information
      • May be used to provide any additional information. [Comment: If you must include useless denials of responsibility, keep them confined to this section]
  • Safety of a common household products: try this search engine, Scorecard
demonstrate proper handling and disposal of chemicals
Demonstrate proper handling and disposal of chemicals
    • http://www.chem.uky.edu/resources/stockroom/watse.html
  • A. The purpose of this section is to assist you in proper handling and disposal of hazardous chemical waste. If at any time you are unsure how to deal with wastes, immediately consult your teacher.
  • B. 5 Most Common (Deadly and EPA-Fineable) Errors In Waste Handling
    • Even experienced laboratory workers have a tendency to become lax or complacent in the laboratory when they are "just cleaning up". Most serious laboratory accidents occur during cleanup, when one's attention is more focused elsewhere.
5 most common deadly and epa fineable errors in waste handling
5 Most Common (Deadly and EPA-Fineable) Errors In Waste Handling
  • 1. Improper Labeling of Waste
    • Failing to label a waste bottle. If the contents of the bottle are not listed, the next person to use the bottle could accidentally combine incompatible chemicals, causing a fire and explosion
    • Storing waste in a bottle lacking the words "Hazardous Waste". Only these exact words must be used. "Organic Waste", "Xylene Waste" etc. are unacceptable. If something isn't really waste, don't put the word "waste" on the bottle. Label it "used" etc.
    • Scratching out the former contents of the bottle and writing "Waste" on the bottle. You must remove or totally deface the old label so there is no confusion over the contents. "Waste" is an unacceptable term to the EPA or OSHA -- the words "Hazardous Waste" must appear on the bottle.
5 most common deadly and epa fineable errors in waste handling1
5 Most Common (Deadly and EPA-Fineable) Errors In Waste Handling
  • 2. Improper Segregation of Waste
    • Storing acids and bases in the same cabinet. Leaking containers or a spill could cause a violent reaction which would release large quantities of toxic gases.
    • Storing acids and organic waste in the same cabinet. In the event of accidental mixing, a catastrophic fire or explosion could result.
    • Mixing incompatible chemicals in a waste container. For example, nitric acid and ethanol can form an explosive mixture.
5 most common deadly and epa fineable errors in waste handling2
5 Most Common (Deadly and EPA-Fineable) Errors In Waste Handling
  • 3. Improper Storage of Waste
    • Storage of waste in a fume hood where reactions are being carried out. If your reaction gets out of control, the waste bottle could explode and lead to a catastrophic fire or mixing of incompatible chemicals. Always remove waste bottles from hoods where reactions are being performed.
    • Using metal cans for waste. Even near neutral pH, solids and liquids can easily corrode through metal cans in a surprisingly short period of time. Use only glass or polyethylene containers for waste.
    • Storing flammable waste containers on a bench or floor. Store your waste containers in a cabinet, preferably an explosion-resistant solvent cabinet.
    • Storing waste bottles in or near a sink or floor drain. This could allow toxic chemicals to enter the sewer, contrary to EPA regulations.
5 most common deadly and epa fineable errors in waste handling3
5 Most Common (Deadly and EPA-Fineable) Errors In Waste Handling
  • 4. Failure to Cap Waste Bottles
    • Leaving the cap off an organic waste bottle. The only time a cap should be off a waste bottle is when you are actually putting waste into it. If you are afraid of a pressure buildup in the bottle, simply cap it loosely.
    • Leaving a funnel in the waste bottle. When you are done with it, cap it!
5 most common deadly and epa fineable errors in waste handling4
5 Most Common (Deadly and EPA-Fineable) Errors In Waste Handling
  • 5. Accumulation of Excessive Waste
    • Ideally, you should have no more than ONE bottle of each kind of waste in your laboratory. If the organic waste bottle is full, notify your teacher for proper disposal.
demonstrate proper handling and disposal of chemicals1
Demonstrate proper handling and disposal of chemicals

C. How To Segregate Waste In The Laboratory

1. The guidelines for temporary storage of chemical wastes in the laboratory are really no different than those that you use for the storage of your usual lab chemicals. The most important rule is to make sure that any chemicals or wastes that stored together are compatible with each other! Proper segregation of wastes involves making sure that wastes within a bottle are compatible, but it also means that you should NEVER store the following types of wastes near each other:

demonstrate proper handling and disposal of chemicals2
Demonstrate proper handling and disposal of chemicals
  • Acids and bases.
  • Organics and acids.
  • Cyanide, sulfide or arsenic compounds and acids.
  • Alkali or alkali earth metals, alkyllithiums etc. and aqueous waste.
  • Powdered or reactive metals and combustible materials.
  • Mercury or silver and ammonium containing compounds
demonstrate proper handling and disposal of chemicals3
Demonstrate proper handling and disposal of chemicals
  • Self-Auditing Checklist For Hazardous Waste Generators
  • ALL hazardous waste containers must comply with ALL of the following requirements at ALL TIMES. If any item on this list is not checked, you are in violation of State and Federal EPA regulations.
demonstrate proper handling and disposal of chemicals checklist
Demonstrate proper handling and disposal of chemicals - checklist
  • Is the container sound? (No cracks, rust or deterioration permitted).
  • Is the container compatible with the waste? (No metal cans, in particular).
  • Are the contents of the container compatible with each other?
  • Is the container properly labeled, including the words Hazardous Waste and a date?
  • Are the contents of the container clearly listed?
  • Is container closed with a properly fitting cap? (Not left with a funnel inserted.)
  • Is the waste container located in the lab (not in a hallway or storeroom)?
  • Is there less than 55 gallons of waste in the laboratory?
  • Is the waste located away from floor drains or sinks?
  • If the container is full, it is being taken to the teacher for disposal.
maintain safety and quality control logs in the laboratory 03 06
Maintain safety and quality control logs in the laboratory 03.06

A. Documents vs. Records

1. A document is: WRITTEN policies, process descriptions, procedures, and blank forms; used to communicate information

2. A record is: Information captured on worksheets, forms, and charts

B. The purpose and functions of a laboratory determines the type(s) of records kept.

C. Proper documentation is needed for safety & quality control in a laboratory

D. Record-keeping allows a lab to minimize error and monitor the lab system .

maintain safety and quality control logs in the laboratory 03 061
Maintain safety and quality control logs in the laboratory 03.06
  • E. Examples of records which could be kept at a laboratory
    • 1. Specimen transfer logs
    • 2. Lab / Test register
    • 3. Temperature logs
    • 4. Equipment maintenance logs
    • 5. Inventory records
maintain safety and quality control logs in the laboratory 03 062
Maintain safety and quality control logs in the laboratory 03.06
  • F. Good record keeping requires:
    • 1. Understand the information to be collected
    • 2. Record the information every time
    • 3. Record all the information
    • 4. Record the information in the same way every time
maintain safety and quality control logs in the laboratory 03 063
Maintain safety and quality control logs in the laboratory 03.06
  • G. Records Should be Permanent, Secure, Traceable
    • 1. Permanent: Keep books bound, number pages, use permanent ink, control storage
    • 2. Secure: Maintain confidentiality, limit access, protect from environmental hazards 3.Traceable: Sign and date every record
maintain safety and quality control logs in the laboratory 03 064
Maintain safety and quality control logs in the laboratory 03.06
  • H. Examples of records
    • 1. Lab records may be kept on laboratory notebooks. Notebooks can be purchased special for the lab or a regular spiral bound notebook may be used.
  • I. In the Medical Forensics Lab:
    • 1. You will be required to keep your own laboratory record in your own laboratory notebook. This notebook needs to be 70 pages and bound. The records kept in the notebook for each unit will vary. At the beginning of the laboratory exercise, the instructor will demonstrate how to set up your notebook for that particular exercise.
demonstrate proper use cleaning and storage of a compound microscope and steroscope
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • A. Types of microscopes
    • 1. Compound microscope.
      • A. The eyepiece system may be monocular, binocular, or trinocular.
      • B.Monocular observation uses one eyepiece, binocular observation uses two. Trinocular microscopes contain an additional upright ocular which is utilized when the microscope is used with a photo or video system.
      • C. Compound microscopes are used to observe small animals in water, sections of plants, and/or animal and plant cells, hair & fibers
demonstrate proper use cleaning and storage of a compound microscope and steroscope1
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • 2. Stereo microscope.
    • a. Stereoscopic (3D) vision is possible by the combined action of two eyes.
    • b. This requires an independent optical system for each eye (similar to how binoculars work).
    • c. A stereo microscope has two tubes with independent optical systems with two eyepieces and two objectives.
    • d. A stereo microscope is a combination of two compound monocular microscopes whose optical axes are at a right angle to each other and directed to the same specimen area.
demonstrate proper use cleaning and storage of a compound microscope and steroscope2
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • B. Parts of a microscope
    • 1. Eyepiece (Ocular)—contains lenses to increase magnification. It may be replaced with lower or higher magnification.
    • 2. Body Tube—holds lenses of ocular and objectives at the proper working distance from each other.
    • 3. Nosepiece—permits interchange of objectives.
    • 4. Objectives—Contains lenses of different magnifications: usually low, medium and high power objective magnifiers.
    • 5. Stage—supports slide over opening that admits light from mirror or lamp.
demonstrate proper use cleaning and storage of a compound microscope and steroscope3
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • 6.Stage Clips—holds slide firmly in place.
  • 7. Course Adjustment—moves body tube or stage up and down.
  • 8. Fine Adjustment—permits exact focusing by moving stage or body tube up or down very slightly.
  • 9. Diaphragm—regulates the amount of light passing through the specimen.
  • 10.Light Source—directs light upward through the diaphragm and hole in stage.
  • 11. Arm—supports the body tube and course adjustment.
  • 12. Base—firm support that bears the weight of the microscope.
demonstrate proper use cleaning and storage of a compound microscope and steroscope4
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • How to use a microscope
    • 1. Carry the microscope with one hand on the arm and one hand on the base. Carry it close to the body.
    • 2. Remove the cover and plug in the microscope. If the cord is too long, place the excess cord on the table (do not let the cord dangle over the edge of the table).
    • 3. Always start with the lowest power. Place the slide on the microscope stage with the specimen directly over the center of the glass circle on the stage (directly over the light).
demonstrate proper use cleaning and storage of a compound microscope and steroscope5
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • a. Trouble shooting.
    • (1). If you wear glasses take them off.
    • (2). If you see only your eyelashes, move closer.
    • (3). If using a monocular microscope, cover or close your other eye.
    • (4). If you see a dark line that goes part way across the field of view, turn the eyepiece. The dark line is a pointer that is a very valuable tool when you want to point out something to your lab partner or your teacher.
demonstrate proper use cleaning and storage of a compound microscope and steroscope6
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.

4. On the low power, lower the objective lens using the course (large) adjustment until it is at the lowest point. Then slowly raise the lens using the course (large) adjustment until you see the specimen within the field of view. Then use the fine (small) adjustment to see the specimen clearly.

5. At this point adjust the diaphragm while still looking through the eyepiece. This will allow more or less light. More detail will be seen when less light is allowed in through the diaphragm. Too much light will give the specimen a washed-out appearance.

demonstrate proper use cleaning and storage of a compound microscope and steroscope7
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.

6. Once the specimen is clear on low power, center the specimen in the field of view, then, without changing the focus knobs, switch to the next higher power.

7. Once on this higher power only the fine adjustment can be used. Use of the course adjustment at this point may scratch or crack the slide.

8. The highest power is an oil immersion lens. If this lens is used without oil, it may ruin the lens.

demonstrate proper use cleaning and storage of a compound microscope and steroscope8
DEMONSTRATE PROPER USE, CLEANING, AND STORAGE OF A COMPOUND MICROSCOPE AND STEROSCOPE.
  • How to clean and store a microscope
    • 1. Only use lens paper to clean the lenses. A paper towel may be used to clean the stage.
    • 2. Lower the stage completely.
    • 3. Return the lens to the lowest power.
    • 4. Wrap cords loosely around the microscope and replace the cover.
    • 5. Return the microscope to the storage area carrying the microscope with one hand on the arm and one hand on the base and close to the body.
3 09 identify trace evidence using a microscope
3.09 IDENTIFY TRACE EVIDENCE USING A MICROSCOPE

A. Trace evidence is normally caused by objects or substances contacting one another, and leaving a minute sample on the contact surfaces. At a crime or accident scene, trace evidence is something that can only be detected through a deliberate processing procedure. An individual entering any environment will deposit traces of his or her presence and this material can be used as evidence. There will always be a transfer of evidence but it is very difficult to find and collect this evidence.

3 09 identify trace evidence using a microscope1
3.09 IDENTIFY TRACE EVIDENCE USING A MICROSCOPE
  • B. Types of trace evidence.
    • 1. Fibers
    • 2. Glass
    • 3. Hair/fur
    • 4. Paint
    • 5. Soil
    • 6. Impressions
    • 7. Gunshot residue
    • 8. Blood
identify trace evidence slides
Identify Trace Evidence Slides

Using the Trace Evidence Slide Lab Paper, fill in the table on the paper, being sure to add as much detail to your drawings and descriptions as possible.

You need to have an example for each of the 19 different trace evidence slides.

Your quiz will consist of ten slides set up on a microscope with multiple choice answers.

3 09 identify trace evidence using a microscope2
3.09 IDENTIFY TRACE EVIDENCE USING A MICROSCOPE

C. Location of trace evidence.

1. Weapon

a. Blood/tissue from victim

b. Blood/fingerprints from suspect

c. Fibers

2. Location of crime

a. Blood/tissue from victim

b. Blood from suspect

3. Victim

a. Blood/semen from suspect

b. Fibers

4. Suspect

a. Blood/tissue from victim

b. Fibers

3 09 identify trace evidence using a microscope3
3.09 IDENTIFY TRACE EVIDENCE USING A MICROSCOPE
  • D. Collecting trace evidence.
    • 1. Individuals who collect trace evidence.
      • A. Police Officer
      • B. Crime Scene Investigator
      • C. Forensic Scientist
    • 2. Trace evidence collection methods.
      • A. Visual inspection
        • (1). Use of naked eye or hand lens.
        • (2). Evidence removed and packaged for later analysis.
        • (3). Use bright light and forceps to collect evidence.
        • (4). Small plastic bags, glass vials, or paper using a druggist fold is used to collect evidence. Everything is double packaged and labeled.
collecting trace evidence
Collecting Trace Evidence
  • b. Tape lift
    • (1). Clear tape is used.
    • (2). Repeatedly apply tape to small area until most of the stickiness is gone.
    • (3). Tape is folded back upon itself, taped to a glass slide or taped to a piece of plastic.
  • c. Vacuum
    • (1). Nozzle should be short and transparent.
    • (2). Debris is collected on a filter or membrane.
collecting trace evidence1
Collecting Trace Evidence
  • E. Classifying trace evidence.
    • 1. Most trace evidence is classified using class characteristics.
      • A. Color
      • B. Shape
      • C. Refractive index
      • D. If physical properties differ then they did not come from the same source
collect trace evidence
Collect Trace Evidence

Using the packing tape provided, obtain two samples of “trace evidence,” one from your shirt and one from the bottom of your shoe.

1. Obtain a 3 inch length of clear packing tape, being careful to only touch the very edge of the tape.

2. Press the tape to your shirt/bottom of shoe

3. Carefully peel away the tape and place it sticky side down on the transparency.

4. Using a microscope, make 5 observational drawings of what you see.

5. Identify as many particles as you can (at least 10 per sample)

3 10 prepare a wet mount slide
3.10 PREPARE A WET MOUNT SLIDE
  • A. Wet mount slide preparation.
    • 1. Use a flat glass slide. The slide should be clean and free of dust or other particles.
    • 2. Draw a few drops of the liquid specimen into a medicine dropper.
    • 3. Pick up the glass slide with one hand grasping it by the outer edges.
    • 4. Place one drop of the liquid specimen from the medicine dropper on top of the slide. The drop should be placed in the center of the slide.
    • 5. Do not tilt the slide in your hand.
3 10 prepare a wet mount slide1
3.10 PREPARE A WET MOUNT SLIDE
  • 6. Use your free hand to carefully pick up a cover slip (they are extremely fragile) grasping it by the outer edges.
  • 7. On an angle, place the cover slip on top of the specimen on the slide. The edges of the cover slip should match up with the edges of the slide. DO NOT PRESS DOWN ON THE COVER SLIP.
  • 8. Holding the slide by the outer edges, keep the slide as horizontal and steady as possible. Place the slide on the stage of the microscope. The specimen should be placed over the opening of the diaphragm.
3 11 apply relevant metric conversions
3.11 APPLY RELEVANT METRIC CONVERSIONS
  • A. Metric System
    • 1. Measurement is a major part of the foundation of medicine, science, applied mathematics, and engineering.
    • 2. There are two common systems of measurement.
      • A. International System (SI) of Units, commonly called the metric system.
      • B. United States Common System (USCS).
    • 3. The International System of Units is the system of measurement used in the medical field.
    • 4. The International System of Units has measurements for length, mass, area, volume, and mass density.
      • A. Length: millimeter, centimeter, meter, kilometer.
      • B. Mass: milligram, gram, kilogram.
      • C. Volume: cubic centimeter, cubic meter, milliliter, liter.
3 11 apply relevant metric conversions1
3.11 APPLY RELEVANT METRIC CONVERSIONS
  • B. Metric Units
    • 1. Length.
      • A. The basic unit of length in the metric system is the meter represented by a lowercase m.
      • B. 1 kilometer (km) = 1000 meters.
      • C. 1 meter (m) = 100 centimeters (cm).
      • D. 1 meter (m) = 1000 millimeters (mm).
3 11 apply relevant metric conversions2
3.11 APPLY RELEVANT METRIC CONVERSIONS
  • 2. Mass.
    • a. The base unit of mass in the metric system is the kilogram represented by lowercase km.
    • b. 1 kilogram (kg) = 1000 grams (g).
    • c. 1 gram (g) = 1000 milligrams (mg).
  • 3. Volume.
    • a. The base unit of volume in the metric system is the liter represented by lowercase l or uppercase L.
    • b. 1 liter (L or l) = 1000 millimeters (mL or ml).
    • c. 1 milliliter (mL or ml) = 1 cm3 or cc = 1 gram of water.
lab activity
Lab Activity

3.12 DEMONSTRATE ACCURATE MEASUREMENT USING APPROPRIATE LAB EQUIPMENT: GLASSWARE (VOLUME), TRIPLE BEAM BALANCE (WEIGHT), ELECTRONIC SCALES (WEIGHT), RULERS AND MEASURING TAPES (DISTANCE), AND VERNIER CALIPERS (DISTANCE).

measurement lab
Measurement Lab

Using the paper provided, complete each measurement task as outlined.

Show the teacher your completed liquid measurements and any other measurements as described on the lab paper.

identify microbes
IDENTIFY MICROBES
  • 3.13 IDENTIFY MICROBES USING MEASUREMENT AND MICROSCOPY TECHNIQUES IN A SIMULATED PROFESSIONAL SETTING.
    • A. Microbial forensics uses molecular techniques to analyze microscopic microbes that cause illness or death (i.e., bacteria, viruses, and fungi as well as any pathogenic agent that can be used as a biological weapon). Microbial forensics includes the full scope of forensic evidence, such as analysis of microbes, materials used to prepare, stabilize, and deliver the toxin or pathogen, and fingerprints, hair, fiber, and pollen.
    • B. Laboratory analysis used in microbial forensics including molecular sequencing, microbiological cultures, biochemistry, electron microscopy, crystallography, and mass spectrometry.
lab assessments
Lab Assessments
  • In this unit you should have completed the following lab assessments:
    • Hand washing
    • PPE donning and removal
    • Trace evidence
    • Measurement
test for unit 3
Test for Unit 3

Your test for this unit will consist of multiple choice questions.

Anything discussed in this unit from your notes could be on the test. With regards to the MSDS sheets, you do not need to know specifics about the regulations on MSDS, just what they are for and how to use them.