Crime Busters B

[Skink]

Nobody has yet reported in after having done this soil deal. Have you seen it at a competition yet? If so, what did they ask? I would check the sites linked on the National site (not the CB notes but the others) to see if you can find anything.

[ssb4ever]

Well, I read on the rules that some test may contain comparisons with soil compositions and suspects, but I have not yet seen this on a test . I have also heard from former team members competing in Crime Busters that they may have encountered them. Thanks anyway!

[JustDroobles]

Well, I read on the rules that some test may contain comparisons with soil compositions and suspects, but I have not yet seen this on a test . I have also heard from former team members competing in Crime Busters that they may have encountered them. Thanks anyway!

I had soil analysis on my MI state Forensics test two years ago. Basically we needed to know what colors corresponded with which substances in the soil.

-White or light grey - Silica
-Black, dark brown, or dark grey - Humus
-Red, Brown, Yellow - Iron

[ssb4ever]

Ok thanks!!

[ewolf1230]

thanks!

[Harrylovecraft]

For chromatography, usually how long will you have to wait until you take out the chromatography paper? Our team has been practicing for past few days and we really cant tell when to stop. Any advice?

[JustDroobles]

For chromatography, usually how long will you have to wait until you take out the chromatography paper? Our team has been practicing for past few days and we really cant tell when to stop. Any advice?

I would say a few minutes. I would leave it in until the solvent front has reached about 1 cm from the far end of the paper for the clearest results, but if that takes too long you can take it out sooner. What is important is that you can clearly see pattern of the pigments. Make sure you mark where the ink started and the solvent front when you removed the paper. The rf value should be the same no matter how long you leave it in because it is a constant ratio between the distance the substance traveled and the substance the solvent traveled.

[Thermal-Underwear]

How many paragraphs should the crime buster essay need? Does it need a introduction or conclusion paragraph or just one paragraph is sufficient? Also, what are polymers specifically? And what is the solvent used in paper cromatography? Thanks

[Skink]

1. The suggested length for your essay is however long it takes to convey your ideas to get full credit. Give a complete answer, not one full of fluff. Don't leave anything out, either.

2. Start here or here.

3. The mobile phase is most easily water but doesn't have to be. Ensure it's something that whatever you're testing is soluble in so that it actually moves.

[awesome90220]

Hey Skink, this wasn't a very good test either. They only told us what each person had in vials, no background info