r k 8.02 Blood Spatter Lab & CER Report STEP 1: Read this worksheet in its entirety. Complete all activities and questions. STEP 2: Complete CER Report using this template STEP 3% Submit the Lab worksheet & Template to your 8,02 Assignment Materials: Simulated blood Samples, yardstick, metric ruler Oblective: Determine how angle affects blood spatter and to apply this to a mock crime scenario Backaround: Forensic scientists examine bloodstain patterns to help determine the events surrounding 3 crime scene involving blood spatter. The unique arrangement of the blood spatter can tell a story, Blood spatter is just a collection of blood spots that may be different sizes and shapes formed by a variety _of methods. Blood will spatter when an outside force breaks the surface tension of a blood drop. In other words, blood will not spatter until it hits a surface. Blood spatter is typically in the shape of an ellipse (a closed plane curve like an oval or circle). Mathematically speaking, the width and Jength of an ellipse have a unique relationship. By figuring out the ratio of the two and using a trigonometric function, scientists can determine the angle of impact at which the blood spatter occurred. This can help investigators recreate a crime scene or confirm a suspect or victim's story. Look at the following example: The width of the blood spatter above is 16 mm and the length is 24 mm. To determine the ratio between the two, divide the width by the length, Convert the ratio to an angle measure using a table of trigonometric ratios (see Table 1) or by using the sine function on a scientific calculator Steps to follow when using 3 trigonometric table 1. Divide 16 by 24 (.6667) 2. Look atthe chart and find the number .6667 under the Sine column 3. The number falls between 6561 and 6691 on the table. it is closer to 6691 4. 6691 corresponds to the angle measure 42 5 If you are going to calculate the angle using a calculator, follow the directions in your calculatormanual for the sine function 6 In conclusion, blood spatter that is 16 mm wide and 24 mm long hit the surface at approximately a 42" angle N
