PIDDLE TEST. Color Odor Ph. Suspect #1. Suspect #2. Suspect #3. Crime scene Piddle Sample

Transcription

1 PIDDLE TEST Color Odor Ph Suspect #1 Suspect #2 Suspect #3 Crime scene Piddle Sample

2 PROBLEM: PIDDLE TEST Someone has been looking in the window of the Settle household during the early evening hours. Police have discovered that the daughter of the home has had problems with a former boyfriend that has threatened to hurt her. The police have gathered a urine sample for two individuals and a third sample from a deep dish that was under one of the window at the residence. PROCEEDURE: Use the provided cabbage juice to gradually add drops till color changes to determine ph of the urine. Use the chart below to determine hydration, and the standard observation skills to determine if the evidence matches the sample collected from the window at the residence. You may also record color and compare general appearance. Help the police narrow its suspect pool. THE SCIENCE BIT: Activity that explores basic chemical components of fake urine and how that urine reacts to purple cabbage juice that is used as an indicator of ph of a substance whether it is an acid or a base substance,

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4 EXTRACT YOUR DNA DNA is a complex molecule that is found inside cells. This molecule is so small that you can't normally see it with the naked eye, but if you release the DNA of thousands of cells at the same time, the molecules become visible because of their sheer number. In this experiment, you will collect some cells from the skin on the inside of your mouth, break the cells open, release the DNA and concentrate them in a liquid so you can see them. Gather the following household materials: 4 ounces of drinking-water (approximately ½ cup) 1 eyedropper or spoon 1 Tablespoon of salt 1 drop of clear dishwashing soap 1 clear cup or glass 1 stir stick bottle of chilled rubbing alcohol in pail blue food coloring (opt) Step 1: Add 1 Tbsp. salt to ½ cup water and stir until the grains of salt have disappeared. Step 2: Gargle and swish all the salty water from the cup around your mouth. Do not swallow the water. Spit it back into the cup.

5 EXTRACT YOUR DNA #2 Step 3: Dip the stir-stick in the drop of dishwashing detergent or drop one drop of soap and gently stir it in the cup. Less froth in the cup is better so stir only two or three times. Step 4: Add one drop of food coloring to the salt water solution.the blue food coloring will help you distinguish the alcohol from the water. Step 5: Use the eyedropper to dribble the chilled rubbing alcohol down along the inside wall of the cup. Try to add the alcohol very gently, so that the water and the alcohol do not mix. You want the alcohol to form a separate layer on top of the water. It helps to hold the cup at about a 20-degree angle while you do this. Step 6: Watch the thin strands of DNA collect together in the alcohol. The strands link together and form nets or webs of DNA. If the alcohol is cloudy, try the experiment again and add the alcohol more slowly. Discard the contents of the cup.

6 THE SCIENCE BIT What happened? The skin cells inside your mouth were easily removed by gargling and swishing the water in your mouth. Salty water was used because it mimics the salty fluids inside our bodies. Our cells are protected by walls that are really a fatty layer called a membrane, but when you added the drop of detergent you broke open the cell membrane and the DNA was released into the water. When the alcohol layer was added the DNA strands gradually migrated into it and joined to other DNA strands. As more and more strands stuck together, the DNA became visible to the naked eye. Isn't it amazing that such tiny molecules hold all the information to make you so unique?

7 CAST ME UP Many times there is the need to make a cast of tool prints left at crime scenes. You will learn how to make a replica of the tool marks in order to determine the origin of the marks left behind. SUPPLIES: plaster of Paris bowls spoons clay disposable Pans magnifying glass microscope timer DIRECTIONS: 1. Take each tool and make an impression in pieces of clay 2. Mix the plaster of Paris using 1/2 cup to about 1/8 cup of water. This mixture is good for about 30 minutes, so work quickly. Spread mixture and pour into the clay impression of the tools. 3. Let set for about 1 2 hours and then lift out of the sand and examine according to the actual tools. Make your comparisons and examine for distinguishing marks THE SCIENCE BIT: Using plaster of Paris to cast ear prints that are unique to each individual just as fingerprints utilizing a chemical reaction of the plaster to set the ear print in stone.

8 POWDER ANALYSIS THE SCIENCE BIT: A forensic scientist may discover powder at a crime scene. In order to determine if it is illegal or not the crime lab will identify the substance using chemistry. Take on the role of a forensic chemist to identify unknown substances determining acid and bases in everyday chemicals. 1. Place one-fourth teaspoon of the four white powders on a sheet of black construction paper. Label the powders with the white chalk or white crayon. Test each with all liquids/record. 2. Study the powders with the magnifying glass. Examine what each powder looks like. How would you describe the powder's texture? Does it have large or small grains? Your observations should be written in the appearance column of the chart. 3. Examine the powders further by rubbing each powder between your fingers. Describe how each powder feels in the Texture column. 4. Determine if there is a smell to any of the powders. Record your findings in the Smell column of the chart. 5. Take the eyedropper and place a drop of water on each individual powder. Examine what happens? Do the powders dissolve? Is there a reaction? Write your observations in the Reaction to Water column. 6. Place one-half teaspoon, add 1 drops of iodine using the eyedropper. Record what happens in the Reaction to Iodine column. Iodine should be handled with care.

9 POWDER ANALYSIS

10 PROBLEM: There has been a note left at the crime scene of a bank robbery, and the crime scene investigators want to examine the type of ink used to write the not in order to get a pool of suspects. PROCEEDURE: Use the pens in the lab to set up a procedure that will separate the colors in a spectrum, as all black ink has different components and colors. This will help you find your suspect. Make a small dot on the end of the coffee filter paper, using a new strip for each pen. Bend the edge of the filter over the edge of the cup, while allowing the tip of the filter where the ink spot is to touch the alcohol in the cup. Now watch the colors appear!!!

11 Paper Chromatography Lab Marker # Colors observed in ink sample Questions: What colors did your group observe in each of the black ink samples? Do the colors occur in the same order and in the same location on all the samples? Explain. Did some ink samples not work? Why? Chromatography Challenge Identify the pens used for each of the Mystery Marks. 1st Test each of the Mystery Mark strips you completed in first of experiment 2nd Compare your strips to the Mystery Mark Strips 3rd Write the number of the pen that you think matches each of the mystery marks in the space on your worksheet. 4th Keep trying until you are able to identify all 6 pens! Pen A matches # Pen D matches # Pen B matches # Pen E matches # Pen C matches # Pen F matches #

12 IMPRESSIVE EVIDENCE Tire Tracks Challenge Materials Needed: 11 samples of tires Copies of Tire Tracks magnifying glasses 11 identification cards gloves safety glasses Activity Directions: 1 Examine each of the tire samples and make a comparison to the tire tread prints. 2. Each of the tire samples have the tire brand, that particular style of tire, and the size of that tire. Use the magnifying glass and the hand-held microscopes to compare the actual samples with the imprinted samples. 3. One of the imprints was found at the crime scene an your job is to identify which of the tires were on the car driven by the suspect. 4. Record your results. Solve the crime THE SCIENCE BIT: Everything leaves it s own unique imprint when left and moved from substances. Leaving tire thread marks are signs of evidence for evaluations.

13 Bite Mark ID 1.Make an Impression Follow the directions to create a bite mark impression. Use a ruler to make the measurements needed to the nearest tenth of a centimeter and record your data in the table below along with any notes regarding unique characteristics you observe in the teeth. JAW LENGTH DEPTH UNIQUE CHARACTERISTIC MAXILLA MANDIBLE 2. TASTY TESTING Record your results from your tasty testing TYPE OF CANDY QUALITY POOR, FAIR, GOOD OBSERVATIONS

14 TAKE A BITE OUT OF CRIME Directions: Part 1: Make an Impression Distribute Styrofoam plates and permanent markers to each student. Instruct students to bend the plate in half so that the top of the plate is on the inside. They need to label one half with "maxilla and one half with "mandible". Demonstrate how to make a bite mark impression on the plate. Students will need to put the folded plate in their mouth as fall as possible and bit down on it to make a good impression. They should not bite too deep as to break through the plate. Provide each student with a piece of clear transparency and a permanent marker. They will need to place the plastic on top of their impression on the plate and use a permanent marker to trace the dental pattern onto the plastic as accurately as possible. Have students unbend the plate and use a ruler to make the required measurements for width and depth of the impressions on both jaws. They will also need to note any unique characteristics they observe, such as slanted teeth, spaces, evidence of braces, etc. Part 2: Tasty Testing Pass out one piece of one type of soft candy to each student. Instruct students to gently bite into each piece of candy In too hard to bite it in half. order to make an impression, but not Have the students record a rating for the quality of the impression (poor, fair, good) along with their observations, such as candy sticking to their teeth or whether or not it was too hard/soft to make a good impression. Repeat the testing with the other types of soft candy available.

15 CASTING THOSE PEARLY WHITES Many times there is evidence of bite marks left at the crime scene. Casting bite marks allows for matching and further study of the impressions left as forensic odontology. SUPPLIES NEEDED: dental mold trays carving tools salt flour water bowl spoons storage container salt dough recipe for dental impressions clear plastic wrap plates paint brushes skewer HOW TO DO THE ACTIVITY: 1. Use the dental salt dough recipe to mix up dough that is soft and fluid enough to fit in the dental mold tray. 2. Place a piece of plastic wrap across the dental mold device and then put the dough in the dental mold tray and insert in the mouth. 3. Have the suspect bite down on the dough hard enough to leave a deep impression in the dough 4. After a short amount of time, remove the dental tray from the mouth and use the plastic wrap to eject the mold from the tray and lay it on a plate to dry, which might require over night to cure completely. 5. After the impression is completely dry and hardened, students can use the carving tools or skewer to clean up the impression so the teeth are distinct. You may paint if you want. THE SCIENCE BIT: Bite marks, lip prints, fingerprints, and ear prints are unique to each human being. Making castings and studying the uniqueness of the marks will lead to the person leaving the mark.

16 SALT DOUGH DENTAL RECIPE Basic Salt Dough Recipe used to make a cast of fingerprints for further examination. Ingredients: 1 cup of fine salt 1 cup of flour 1/2 cup of water (may add more) Instructions: In a large bowl, combine the salt and the flour Make a well in the salt/flour mixture and add the water Knead until smooth and shape into a ball When not in use, wrap in plastic or store in an airtight container HINT: To get softer dough you can add more flour. Adding more salt will lend a more granulose affect. Use wallpaper glue and the dough with be more cohesive. To add color to your dough, use different types of flour or add food coloring or paint. Knead to get an even color. You may also paint your project and sculptures after they dry

17 TASTY TONGUE CHART MYSTERY CUP BITTER SOUR SALT SWEET CUP #1 CUP #2 CUP #3 CUP #4

18 WHICH WAY DID IT GO Every good Crime Scene Investigator must be able to determine the direction that the crime came from and be able to use the mathematics of angles and trajectory to determine the ultimate origin of the crime. This activity will have students examine the victims that have severe head trauma to determine the direction that the crime originated from. SUPPLIES: foam heads markers compass protractor skewers calculators magnifying glasses measuring tape DIRECTIONS: Set up the victim so the investigators are able to insert the dowel rods into the existing path of the bullet through the victim s head. After inserting the dowel rods use the protractor and compass to determine the angle of the entry wound. Speculate as to the height of the object or building that the victim must have been shot from in order to sustain the wound at that angle. If you want to do more than speculate this requires higher math skills for the investigator. Otherwise, just brainstorm as to the height THE SCIENCE BIT: This activity will measure the angle of an object penetration and exit of that object. Use of protractors and compasses will determine entry and exit angles

19 WHICH WAY DID IT GO Record Your Data POINT OF ENTRY ANGLE OF ENTRY ANGLE OF EXIT WOUND

20 Balloon Prints 1. Chose a finger. Press your finger pad straight down onto an ink pad, or gently color it with a marker. 2. Press your inked finger straight down onto the balloon. Don t slide it around or the print will smear. 3. Wait a few minutes for the first print to dry. Then repeat steps 1 and 2 with a different finger and make another print on a clean part of the balloon. Try one more finger if there s room on the balloon. 4. Blow up the balloon slightly so the prints get larger. If they look blurry, let out some air until they are clearer. THE SCIENCE BIT: Using observation skills, being able to evaluate, and analyze the prints left behind on the balloon and discovering how blowing the balloon up allows for greater analysis is part of the higher order thinking skills that are utilized by students during this activity.