Forensics?

faraway
Member
Member
Posts: 5
Joined: December 30th, 2008, 9:35 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by faraway »

What exactly do we need to know for the chromatography? In my experience you have to the chromatography first or else you'll run out of time..
iwtban
Member
Member
Posts: 20
Joined: December 29th, 2008, 6:35 pm
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by iwtban »

what should you include in the analysis of crime? i think it's important, too cause it's like 20% of the test ( hope i'm right). last year, i always sun out of time to write a good analysis. any suggestion?
User avatar
dudeincolorado
Exalted Member
Exalted Member
Posts: 595
Joined: January 31st, 2007, 6:27 pm
Division: C
State: CO
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by dudeincolorado »

it's worth 30 this year.....
Ok this is my first year doing this, but i have done crimbusters, and I know in that you need to include: who did it, why they did it, why you choose them, what things incriminate them, who are innocent, why are they innocent, what things relate to them. Make sure you say who did it but ALSO why the other people are innocent. Hope this helps
SO stressed!
iwtban
Member
Member
Posts: 20
Joined: December 29th, 2008, 6:35 pm
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by iwtban »

oh, thanks, that really helps!
i did forensics last year & it has been my favorites; luckily, this year, in the rule book, they clearly state that the judges need to provide a heat source to perform the flame test. invitationals i went last year, they just gave the candles for the flame test which is really ridiculous. and at my state competition, they did not give any candles or anything, even though there were 8 powders.
so, does anyone do the flame test with candles? can you see the red flame when it's LiCl?
faraway
Member
Member
Posts: 5
Joined: December 30th, 2008, 9:35 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by faraway »

LiCl burns 'carmine red'

What type of instrument would you use to hold the salts in the flame? We used a bacteria scraper :P just something random we found. It worked fine except when we burned a sugar it stuck on the metal...

Also, would you use an electric current to test any of the powders? Some of them when mixed with water have increased conductivity but I really don't think it helps much in identifying.
genes_girl
Member
Member
Posts: 59
Joined: January 23rd, 2006, 5:12 pm
Division: Grad
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by genes_girl »

Let's see here.....

For the final write-up you should include the basics: who did, how you know this, ect. Also why the evidence rules out the other suspects. If there is more than one perpetrator make sure you explain how you know this. So, yeah, basically I agree with dudeincolorado. I tend to subscribe to the more-detailed/more-information/more-facts-is-better theory for this. Not long rambling, but concise with as much support as you can.

For flame tests, my team used nichrome wire and it worked well. There really is no way to avoid sugars caramelizing, you just have to work around it. Cobalt glass can be helpful, but it is up to you. You can really work it either way.

I never used a conductivity tester, we had one in our box but we never used it. You could. It is definitely an option. I recommend a dichotomous key of powders. It works well (especially since you are allowed notes). Just figure out what tests are quickest and will help identify the powders.
Indiana University 2012
-- Bio and Spanish Majors

University of Chicago
-- PhD track Molecular Biosciences: Human Genetics
User avatar
adam124218
Member
Member
Posts: 76
Joined: June 1st, 2008, 7:38 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by adam124218 »

We use nichrome wire as well. It works well as long as you don't handle it too much.

I've never used a conductivity tester; we've never been able to get it to work. You can get along just fine without one.

As far as chromatography goes, does anyone have any suggestions for the disaster that is sheet chromatography (the kind we get to enjoy at Nationals and at my state competition)? Whenever we do it, it ends up as a total mess (especially the juice). How do you do it well on the tiny sheet of paper?
User avatar
4rensicsKonz
Member
Member
Posts: 5
Joined: January 19th, 2009, 6:55 am
Division: C
State: IL
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by 4rensicsKonz »

genes_girl wrote:Yeah, the tests are somewhere between 130 and 200 questions, plus everything you have to do to find the answers. If you finish it ( and well, not with stupid answers) you are god. We came close once...at regionals. But it is both questions on results AND general information on fingerprints, DNA, etc. Don't forget the writeup as well!
130 to 200 question :shock:
oh dear... at least i can still do crime busters for another year
is it hard? or just long?
2011-2012 Events:
Forensics, Disease Detective, Water Quality, and Protein Modeling

2012-2013 Tentative Events:
Forensics, Disease Detective, Water Quality... Circuit Lab?


Image<--illinois!
Go Naperville Central HS
genes_girl
Member
Member
Posts: 59
Joined: January 23rd, 2006, 5:12 pm
Division: Grad
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by genes_girl »

It depends on how well you know the material, how fast you run the tests, and how many stupid mistakes you make (because you can't avoid them). Personally, I think it is mainly just long. People who have never been exposed to that form of test before think it is hard and long though. You just have to make sure you are prepared.
Indiana University 2012
-- Bio and Spanish Majors

University of Chicago
-- PhD track Molecular Biosciences: Human Genetics
User avatar
adam124218
Member
Member
Posts: 76
Joined: June 1st, 2008, 7:38 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Forensics?

Post by adam124218 »

I would say it's hard because it's long. And because the coordinator is screaming at you the whole time. The tense atmosphere is what makes it really difficult. There are so many questions that mistakes are unavoidable, like I mixed up which solution was which for the polymers at nationals and had to do it again (and I think I messed it up again). Things like that reduce your time and consequently reduce your score.
Post Reply

Return to “2009 Lab Events”

Who is online

Users browsing this forum: No registered users and 0 guests