Forensics Lab #2 Reflection

What scientific ideas or theories would help you explain why you are able to use the procedures to analyze evidence?

How has your approach to the lab procedures changed from the first round of labs? Are you more or less confident in your results? Why?

In most of the Forensics labs we did we used some scientific tools to get to our final answer. In The Ink is Still Wet lab as well as the Killer Cup of Coffee lab we had to use the colorimeter to get a final conclusion for the problems. When we used the colorimeter we didn't have background information on tests and testing with colorimeters. During the Killer Cup of Coffee lab I found myself wanting background information on the "poison" and if it really was lethal, and the reality behind the whole lab. Throughout The Ink is Still Wet lab I realized how much simpler the lab would be if we had background information on the ending result of what happens when you put ink with alcohol. For the First Impressions lab, I was asking myself why did we put the non-stick spray on, other than to make it so the cast wouldn't stick. (Which it pretty much did.) I also found myself wondering what forensic specialists would do if they had something that the suspect had bitten, but not a mold of the teeth. What would they do if they had half of the clues, how would they figure out the rest?

My approach to the labs changed as I got more used to the types of labs even though the specifics in them changed each time. For instance each time we used the Logger Pro software we got more accustomed to it and understood it better, even if what we were doing was different each time. Also each time our knowledge of what type of stuff we were covering expanded so we had a better idea on what outcome was needed to get the final answer. For instance even between two of the most recent labs after you did one the other was easier. Those would be the two with the colorimeter. No matter which one you did first the next was a little bit easier because you didn't have to ask questions each time you had to do something new. Well, at least after you did one of them you could set up the colorimeter and start some of the tests before having to ask a ton of questions. For the results we got on each of the labs I don't feel like I got a lot more confident in my results. I don't think I got more confident because each times the vast majority of the labs were different. Even if the labs used the same equipment, the gist of the lab and the main point was different.

What role do multiple observations/experiments play in making good inferences and conclusions in each case?

When is is hard to be precise and how does this affect the confidence in your results? What did you do about this?

When can you rely on "known" data to match up with and when do you need to generate you own? What is the difference?

Multiple observations and experiments give you extra information so you can make good conclusions at the end of each case. For instance, in the soil lab we not only described the general appearance, we also took notes about the pH, conductivity, and water absorption. If we only wrote observations about the conductivity and pH, we would have to make final conclusions about the case based on only those two pieces of evidence. Making a final conclusion with only two sample results would be a lot less informational and a lot less precise. Multiple observations give you better, more precise information, and a more improved conclusions. More information leads to conclusions based on multiple sources of information instead of just the appearance of a cup of dirt.

It's extremely hard to be precise in a lab when the tools you're using are completely foreign to you, and when the answer you're getting is an inference. When you know your answer is a guess, it affects the confidence you have because you can't be certain if it's correct or not. When we used the caliper in the bullet analysis case, it was harder to be precise, and so when we compared our data with different types of bullets we kept in mind that the information we had might not be exact. It was also hard to be precise when we were measuring the lands and grooves. We had to decide which were the lands and which were the grooves. Doing that wasn't always easy, sometimes the lands and grooves looked and felt almost exactly the same. What we did in situations like this, is we kept in mind that our answer might be off by a little. That in mind is was easy to find the correct answer by adding or subtracting a tenth of an inch for the calipers and easy to find the lands and grooves on the charts.

You can rely on "known" data when you can use data you come up with to justify the information. You need to generate your own data when the "known" data isn't from a reliable source or when the information is a known inference, and not known information. The difference is that when you have information given to you as a part of the case, you should use it. But when you don't know where the information came from or it's not "known" data you might not want to use it as it might not be true data.

Blood Splatter Lab #1

Lab Questions:

How did multiple drops at each height affect your results? What is the purpose of multiple trials in an experiment?

What did you discover about the influence of height on blood diameter in a blood spatter? Could you now accurately infer the height at which a blood drop originated based on the diameter of a blood spatter? Why or why not?

Dropping three drops of 'blood' at each height we tested affects our results because by having multiple drops for each height, we could find the average diameter of the blood drops at each height. Finding the average enabled us to make sure that the answers we got were okay and made sure none of our drops were abnormal. The purpose of multiple trials in the experiment was to make sure that our results made sense and didn't give us wrong answers.

I think that the influence height has on the diameter of a blood spatter is that the size of the blood spatter gets bigger the higher (or farther) away you are from where the blood falls. At this point I think I could infer the height at which a blood drop originated at but not super accurately. I think that it would take a bit of time, and a few more tests, to figure out where the blood originated at accurately. Probably with a little bit of time (and math) I could figure out where blood drops originated at but a few more trials with blood drops would be helpful.

For now I'll leave the professional work up to the professionals...

Sound of Science

To a six year old everything in the world is huge except for puppies and kitties and babies. To me being six is very tough -- I have to go to school, tie my own shoelaces, do my homework and make my own bed. Today is different. Today I don't have to go to school. Today I'm going on a trip to a place called Canada. I'm going on a big Thomas, it's like my Thomas the tank engine only it’s bigger than me and not smaller than my hand. Daddy says I get a special seat in the train because Uncle Freddy owns the train and I get to go in the very front.

Right now we are in the car on the way to the train house, we're almost there!

When we got to the train house I was very scared it was very big and very scary. Daddy calls it a station but I told him that train house is the right way to say it and that I am right and he is wrong. I am always right and he is always wrong. When we got out to the area where you get on the trains there were loud noises that hurt my ears and sounded like my baby brother Sammy when he screams. Steam was coming out of the engine that Daddy and Mommy and baby Sammy and I were supposed to get on, it sounded like the water when Mommy washes the dishes.

After we got on the train we headed to the front of the engine so we could see Uncle Freddy. I hear something that sounds like Mommy cleaning the dishes; there are clanks and pangs surrounded by the steam that sounds like water rushing over a waterfall.

I see Uncle Freddy up ahead of us in the train. He smiles and waves to us, I run to him and give him a hug. He leads us through a door and I see where the clanking and panging is coming from, there are two men shoveling small black rocks into a fiery oven that is part of the train. One of the men taps his shovel on the edge of the oven it makes a pinging sound and dings around the engine.

The men keep shoveling the black rocks for a few more seconds; they close the opening to the oven and put their shovels away. Uncle Freddy leads us to the front of the train where you can see out in front.

A voice calls out and it is hard to tell what the man is saying. The doors close on the train and a loud, high sound fills my ears. The train starts moving. I look back and I can see the train house. We start going faster and turn around a corner until the train house has gone away. We keep going faster and the whistle sounds again. We are on our way to Canada.