Wednesday, November 18, 2009
For the foot print you could rely on gravity because you know that the dirt would be pressured to go down towards the center of the earth so if there were a hill you would know that the dirt might have shifted position to be elongated towards the bottom of the hill. This would change both the size and shape of the foot print you were analyzing. You can also rely on the fact that if the person were heavier the footprint would be more compressed and that can help you narrow down your suspects by showing you the approximate weight of the culprit.
How has your approach to lab procedures changed from the first round of labs? are you more or less confident in your results? why?
In round two I had more of an idea of how to complete the procedures because I read all of the instructions instead of only the one I was on. This made me more confident because I felt like I knew what I was doing and felt more able to handle it. I knew why I was doing each step and how it needed to be done in order to be ready for the next step. Overall I felt more prepared.
Friday, October 30, 2009
When you have more information it is easier to make more precise inferences. In the fiber lab we looked through the microscope at three different levels of magnification so we could compare each of them three times and get a better idea of which ones are similar to each other and more likely to be the ones from the killer and what ones cannot be the killer. After that to be sure you chose the rite fiber you burned them and compared the way they burn. In order to find the killer you have to take both tests and whichever fiber matched the fiber on the victim best with both tests is the fiber from the killer.
2. Why is it hard to be precise and how does this affect the confidence in your results? What did you do about it?
It is hard to be precise because it is impossible to be completely still or exact. You could bump the slate under the microscope, not be able to watch the fiber close enough when it burns, not be on the exact right point when you measure the bullets, or accidentally touch the ph measure to the dirt at the bottom. This can affect your confidence in your data by showing that it can't always be perfect and that sometimes you have to rely on your best inference. To fix these problems you can take a second measurement and decide which is more accurate.
3. When can you rely on "known" data to match up with and when do you need to generate your own? what is the difference?
You can rely on known data when you don't have the time or materials to gather the data yourself. Like in the blood spatter lab we had to rely on the known theory of gravity and that it would carry the blood drops to the paper. In our fiber lab we had to rely on the fact that each fabric was the one it was labeled as but we gathered what it looked like under a microscope and when it burned. You should generate your own data whenever you have the ability to. In the dirt lab you have to gather how much ph is in the dirt sample, how much water each sample holds, and how much conductivity is in each sample. One of the things you need to rely on is that the measuring instruments work the way they are supposed to.
Saturday, September 19, 2009
Tuesday, September 15, 2009
My family’s restaurant is packed with native French speakers. They are talking about the same thing that I’ve been thinking about all morning, Veronica. She has been on the front of the newspapers and magazines for weeks and now she’s in the news too. Another group of people arrives to be seated they chat with my mom, who acts as our restaurant hostess, before sitting in the waiting area. Everyone's forks are banging on their dishes as they eat and talk. As a man gets up to leave his chair makes three loud screeches on the floor. He is stopped dead in his tracks when my sister walks through the door smiling. Veronica rushes over and scoops me into a big hug. She is back after so many months of traveling the world to spread the word about global warming.