Forensic Experiments

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Text of Forensic Experiments

. Name: _____________________________ Year & Section: ________ Score: ________ Group no. _____ Date: _____________________ Instructor: _____________________ EXPERIMENT 1

THE COMPOUND MICROSCOPEI. . II. III. Materials: Compund Microscope Drawing: (Draw and label the parts of the microscope). Objective : To know the parts and the correct technique of using the microscope.

IV.

Questions: 1. Give the functions/uses of the following parts of the microscope: a) Revolving nosepiece b) Coarse adjustment knob c) Stage d) Iris diaphragm e) Mirror f) Ocular or eyepiece

g) High power objective h) Low power objective i) j) Fine adjustment knob Mirror

2. Describe briefly and in systematic order the manner or method of properly using a microscope.

3. Give some precautionary measures in the use of the microscope.

4. Name the three general parts of the microscope and give examples of each general parts.

Name: _____________________________ Year & Section: ________ Score: ________ Group no. _____ Date: _____________________ Instructor: _____________________

EXPERIMENT NO. 2 MAGNIFICATIONI. Objectives To manipulate the compound microscope and determine the magnification of the object. Materials Compound microscope, old newspaper, ruler Procedure The size of the image of an object as seen the microscope is several times bigger than its actual size. This means that the object is magnified under the microscope. The following exercises would enable you to determine how many times an object is magnified under the microscope. 1. Cut a small letter e from any newspaper. Measure the actual size of the letter e. Put the letter e in its natural position on a slide. Put a drop of water and cover with a cover slip. Focus under LPO. Observe the position of the letter e under the microscope. 2. Place a ruler along the right side of the stage. Look through the microscope with your left eye, at the same time looking at the ruler with your right eye. Measure the letter e under the microscope. Compute the magnification by dividing the size of the image by the actual size of the object. 3. Turn to high power objective. Can you see the whole letter e? Draw the letter e as seen with the naked eye under the LPO and HPO.

II.

III.

Actual size

LPO

HPO

4. The magnifying capacity of the microscope. The magnifying capacities of the ocular and the objectives are often indicated on them. An ocular x10 with an objective x4 will magnify an image 40 times. Compute the magnifying capacity of your microscope when you are using the following ocular and objectives. Ocular x10 x10 x10 Objective x10 x100 X60 Magnifying capacity

x10 X40 IV. Questions 1. What is magnification? What parts of the microscope are responsible for magnifying images? ______________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ 2. Two microscopes may have different magnification even both are focused under the LPO. Why? ____________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ 3. What kind of objective should be used in studying: a. Whole section of a specimen. _______________________

b. A portion or a section that is very small. _______________

Name:____________________________ Year & Section: __________ Score: ________ Group no. _____ Date: _____________________ Instructor: _____________________ EXPERIMENT 3

BLOOD GROUPING OF FRESH BLOODObjective: To study the techniques of grouping fresh blood by direct method. Materials and reagents: Sterilized p-in, needle or lancet Blood typing Sera Glass slides Procedure: 1. Using a sterilized needle, pin or lancet, prick the ring finger of the subject whose blood group is to be determined. 2. Get a glass slide and place one drop of blood on the left side of the slide and label A, put another drop of blood on the right side and label B. 3. Place one drop of Anti sera A on the blood with label A and a drop of Anti sera B on the blood with labelB. Mix both drop of blood with a stick using the other end for A and B on the other end. 4. Observe under the microscope. 5. The blood group where there is agglutination is the blood type of your subject. Observation: 1. What is the group of the fresh blood of your subject? Why? _________________ ________________________________________________________________ 2. Draw what has been observed under the microscope.

A B 3. What happened when the respective serum was added to the red blood cells? ________________________________________________________________ ________________________________________________________________ 4. What is agglutination? ______________________________________________ ________________________________________________________________ 5. Why agglutination does take place? __________________________________ ________________________________________________________________

Conclusion:

Name: _____________________________ Year & Section: ________ Score: ________ Group no. _____ Date: _____________________ Instructor: _____________________ EXPERIMENT 4

SEMEN AND SEMINAL STAINV. Objective : To study the physical and chemical methods of identifying semen and seminal stains. Procedure: 5. Physical Examination a. Fresh semen: Observe your fresh semen and describe as follows: 1. Odor 2. Color 3. Feel 4. Appearance : __________________________________ : __________________________________ : __________________________________ : __________________________________

VI.

5. Character when exposed to air for half hour: _______________________________________________ 6. Seminal stain: Get a glass slide then place a drop of semen and make a smear using an applicator stick. Air dry then heat fix using an alcohol lamp. Stain by flooding the glass slide with methylene blue for 1 minute. Then wash with water and let dry. Observe under oil immersion objective Observation: Draw what you have observed in both cases:

VII.

Fresh SemenVIII.

Stained Semen

Question: 1. Why is dried smear stained with methylene blue? ________________________________________________________________ ________________________________________________________________ 2. Is the microscopic examination a specific test for semen and seminal stain? Why? ________________________________________________________________ ________________________________________________________________ 3. If no spermatozoa are observed under the microscope can we conclude that there is no semen? Explain. ________________________________________________________________

________________________________________________________________

Name: _____________________________ Year & Section: ________ Score: ________ Group no. _____ Date: _____________________ Instructor: _____________________ EXPERIMENT 6

TEST FOR HAIRI. Objective : To distinguish human hair from animal hair. Procedure: 1. Preliminary examination Get human and animal hair from the specimen collected and observe: Qualities Human Animal Color Texture Appearance Length Diameter/ Width 2. Microscopic Examination A. Anatomical parts On a separate slide place human and animal hair. Add a drop of water and cover. Illustrate observation and label the three anatomical parts.

II.

Human hair

Animal Hair

B. Medulla Place human and animal hair on separate slide. Add a drop of water and cover with glass slip. Observe and draw your observation.

Human hair

Animal Hair

C. Cuticle (Scale Pattern) - Place human and animal hair on separate slide. Add a drop of water and cover with glass slip. Observe and draw your observation.

Human hair

Animal Hair

III.

Observation: 1. Describe the Medulla in each case. Human _____________________________________________________________ ___________________________________________________________________ Animal Hair _________________________________________________________ ___________________________________________________________________ 2. Describe the scale pattern observed. Human _____________________________________________________________ ___________________________________________________________________ Animal Hair _________________________________________________________ ___________________________________________________________________ 3. Describe the pigment distribution in each case as observed. Human _____________________________________________________________ ___________________________________________________________________ Animal Hair _________________________________________________________ ___________________________________________________________________

IV.

Question: 1. Differentiate human hair from animal hair based on your findings. ________________________________________________________________ ________________________________________________________________ 2. What microscopic examination of hair will determine whether it is human or animal of origin? Why? ________________________________________________________________ ________________________________________________________________

Name: _____________________________ Year & Section: ________ Score: ________ Group no. _____ Date: _____________________ Instructor: _