In this activity you will be replicating the methods crime science investigators use to analyze blood splatter. Instead of a crime scene, you will be working in a corner of a room that you have carefully covered with white paper or white drop sheets. Instead of actual blood, you will be using a blood substitute that you make from mixing cornstarch, water, corn syrup and red and blue food coloring. According to Science Buddies, start by soaking a sponge in the blood solution, and then place it in on the floor, in the center of your prepped space. Strike the sponge with a hammer, and observe the splatter that appears on the walls. You should notice that the splatter spots form small ellipses.
Calculate the direction from which a particular ellipse came by lining up a string with its long axis. Determine the angle--according to Science Buddies--by first measuring the width and the length of the ellipse that makes up the main area of a blood spatter mark. Divide the width by the length, then look up the arcsine of the result. You can use the Arcsin(x) calculator at AnalyzeMath. (See Resources.) That is the angle.
Tape the string above the ellipse and, using a protractor as a guide, pull the string out from the wall in the direction and angle you just determined.
Repeat this process for several blood spatter marks. If you perform the experiment correctly, the strings should end up in the precise spot where you struck the sponge.
Blood is very similar from person to person. However, there are several distinct varieties of it, which vary on the microscopic level. These varieties include type A, type B and type O. While some blood types are compatible, such as B and O, allowing doctors to use them interchangeably in transfusions, others---such as A and B---are not. According to Julian T. Rubin, you can re-create how different blood types interact using blood substitutes. To make type A blood, mix together floor polish, water and red food coloring. To make type B, mix vinegar, water and red food coloring. And to make type O, mix water with red food coloring. When you mix the type B with the type O, you should notice that there is no reaction, and the fluid remains stable. However, when you mix type A with type B, the solution will congeal and lose its fluidity.
The objective of this project is to identify and re-create the four basic components of blood. These components are red blood cells, which transport carbon dioxide and oxygen; plasma, which transports wastes and dissolved foods; white blood cells, which fight off germs and absorb old cells; and platelets, which help your blood clot. According to Steve Spangler Science, mix together in a cup some red hot candies, to serve as your red blood cells; some corn syrup, to serve as the plasma; some white jelly beans, to represent the white blood cells; and some candy sprinkles to represent platelets. Not only is this hands-on activity fun, but the end result is completely edible.