Fiber Lab: February 11, 2009

Fiber Lab 

Annabella Sherman

Wednesday, February 11, 2009

Partners: Ayanna and Natalie

Core: Y & A

Summary

Today me, Ayanna and Natalie did the Fiber lab. We were given a case where a women was murdered. A few different fibers were found on her coat, but only one wasn't from her house or her clothes. The "mystery fiber" was red. There were six suspects that have red coats. Our job was to figure out who committed the murder. 

Today we took each of the fibers and made a "wet slide." To do this, we placed a small sample of each of the fibers onto transparent sheet and added a drop of water. Then we put a smaller sheet (or a "glass cover") on top of it. The water caused it to stick easily so we could see it better. First we did it to the fiber found at the crime scene. Then we did it to the other six fiber samples and tried to find out which one was most like the fiber found on the victim's coat. We observed them under the microscope on three different levels - low, medium, and high. It was really cool to see all the different levels of magnification! I never would have known the fabrics were so delicate and cool up close!   

Guiding Questions:

Can you use fiber evidence to identify its source?

I think you can definitely use fiber evidence to identify its source. Like we did, you can observe the crime scene fiber first, and then observe all the suspect fibers and see which ones are most like the crime scene one. If there isn't a clear result from the suspect fibers, you can also burn the fibers and see which one has the same result as the crime scene fiber. If both of these strategies don't produce a clear result, you can probably do another test, such as scent or feel. Maybe you could add water or a certain chemical or liquid and see if it works. I think maybe this would work, since we have done that for most of the other science labs I did. I'm sure there are many other ways to test the fibers as well.

How might this lab be helpful in preparing you for the Mission?

I think this lab will be very helpful in preparing me for the Mission. All of the labs have actually been very helpful for me. I know I am definitely well prepared for the Mission!

This lab has prepared me for the mission by teaching me a variety of different skills. For example, I learned how to use a microscope! At first we were stumped on how to work it, but after Darin showed us I had an epiphany, and now I understand it. I have also had some practice doing detailed drawings from this lab. I learned that you have to be very specific in your drawings if you want a good result. The more observant you are, the more data you will end up with in the end. Like all the other labs, the Fiber Lab has also taught me how to be more observant and do a lab/observation to the max!

Urine Analysis Lab: February 9, 2009

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Trajectory Lab: February 2, 2009

How can the angle of impact of a bullet in a wall be used to determine other critical information about the scene of a crime?
Once you find out the angle that a bullet went into the wall at, you can determine where the bullet was shot from. From this information you may be able to determine the height of the person that was holding the gun (when they shot the bullet).
For example, if one if the suspects in a crime was really tall and the other was really short, after analyzing the bullet hole you could figure out what angle the bullet entered, and where the gun was held when the bullet was shot. If the bullet entered the wall from above, the person that shot it would have to be very tall. If the bullet entered the wall from below, the person would probably be very tall. However, sometimes this method does not work, because a tall person may have been crouching on the ground (or lying on the ground) when s/he shot the bullet.
After analyzing the dimensions of the bullet hole, it is also possible to find out what kind of bullet was used in the crime. Once you figure that out, you can also find out what kind of gun was used in the crime, because if you know the size of the bullet you can find out what KIND of bullet was used, and then what gun goes with that kind of bullet.

How might this lab be helpful in preparing you for the mission?
In the mission we may have to analyze different bullet holes and find out who shot them. In this lab, I also learned other important things, such as how to correctly measure things. I learned about millimeters and centimeters, and all the other different methods you can use to measure things. I also learned a lot about angles and using a protractor. I hope these skills will come in handy for the mission!