Forensics?

[adam124218]

The test isn't always like that. It's only really that way with the national coordinator. Other tests can be totally different. Our regional test had a bunch of questions about interpreting mass spectroscopy, but the state and nationals tests didn't go into that much detail at all. Also, at regionals they gave us these pathetic microscopes, one of which was little better than a hand lens--it's highest magnification must have been about 4x--and the other which had so many dials that even the students who were running the event couldn't figure out how to use it. There's so much variation in what will be on different tests.

Has anyone managed to find pure spandex to test? We've never been able to find it because everything is a spandex blend.

[genes_girl]

Sorry, I thought it was just in reference to nats. The others vary, but the powder sections tend to stay the same- what is it, how did you identify it, who does it incriminate.

As for the spandex, no, not really. We never really put too much effort into it, we looked up differences between man made vs. organic and other aspects that depending on how they react to flame would narrow it down until we knew what it was.

[Freak of Science]

In response to the post regarding compounds to be used in a flame test:

I take it that it is necessary to both use a reaction test to determine a carbonate or bicarbonate, as well as a flame test to figure out the metallic compound it is binded to?

[genes_girl]

We never had to use a flame test to identify carbonate vs. bicarbonate and which one it was. You should be able to tell just using HCl and Water. HCL for your reaction test and then water for consistency/dissolves/doesn't dissolve/other and pH.

[adam124218]

So I was looking at the Chem Lab page on the national website, and I think the picture accompanying it is a picture of Forensics from nationals. I'm pretty sure I'm right. In fact, I'm positive, since I did both of those events at nats and that's definitely Forensics. Can anyone agree with me?

[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]

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?

[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

[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]

LiCl burns 'carmine red'

What type of instrument would you use to hold the salts in the flame? We used a bacteria scraper 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.