Crime Busters B

[starfruit]

Which should I study harder, blood stains or ph?

I would study ph levels much harder, because they can apply to identifying both liquids and powders. Blood spatters are fine if you have a basic understanding, but you don't need to spend much of your time studying them.

[bigfatcat24]

hi i was wondering if they are testing powders in the first competition and if so what powders?

[starfruit]

hi i was wondering if they are testing powders in the first competition and if so what powders?

Yes, they have always had powders when I've competed, and the powders can be any of the 13 powders in the rules. You won't know what they are until you test and identify them.

[builder83]

1. Will hair samples be given on a slide? Or will we have to put them on a slide?

2. Chromatography: After running a test with juice or ink, what next? Will they be compared against given tests?

3. Mixed substances. Is there a good resource on how to determine these?

[amk578]

1. Will hair samples be given on a slide? Or will we have to put them on a slide?

2. Chromatography: After running a test with juice or ink, what next? Will they be compared against given tests?

3. Mixed substances. Is there a good resource on how to determine these?

1. Sometimes they will be given on a slide, but I've seen in the past where they require you to put it on slides with the slip covers (not sure if they changed the rules).

2. They will most likely provide given tests to compare against. Another thing that may be asked of you is the retention factor of the chromatography.

3. I believe mixtures will show qualities of both substances in there (if that makes sense), but I'm not sure about a finite resource for researching this. The best thing to do would be doing practice tests on identifying with kits.

[builder83]

1. Will hair samples be given on a slide? Or will we have to put them on a slide?

2. Chromatography: After running a test with juice or ink, what next? Will they be compared against given tests?

3. Mixed substances. Is there a good resource on how to determine these?

1. Sometimes they will be given on a slide, but I've seen in the past where they require you to put it on slides with the slip covers (not sure if they changed the rules).

2. They will most likely provide given tests to compare against. Another thing that may be asked of you is the retention factor of the chromatography.

3. I believe mixtures will show qualities of both substances in there (if that makes sense), but I'm not sure about a finite resource for researching this. The best thing to do would be doing practice tests on identifying with kits.

Thanks for the quick response! I have the kit. I just did not know if there was a different way to figure out mixtures. We should be able to figure them out with ph, water, hcl, and iodine right? Guess I'll just mix some and see what happens!

[ledwards003]

I was wondering what liquids are typically used to test density, as I have been given the liquids before without knowing their density and would like to be able to figure that out. I cannot out what find the liquids used for testing density are anywhere, so if anyone could help I would really appreciate it. Thank you!

[Person]

I was wondering what liquids are typically used to test density, as I have been given the liquids before without knowing their density and would like to be able to figure that out. I cannot out what find the liquids used for testing density are anywhere, so if anyone could help I would really appreciate it. Thank you!

Haven't done Crime Busters before, but the ones I had on my Forensics notes for density were corn oil, 46% isopropyl alcohol, and 10%/25%/saturated NaCl solution.

[scipanther55]

Hey Guys,

Wondering if we are allowed to conduct a scratch test for metals?

Also,
Does anyone know what liquids they will provide when testing the density of plastics?

Thanks

[Galahad]

Hey Guys,

Wondering if we are allowed to conduct a scratch test for metals?

Also,
Does anyone know what liquids they will provide when testing the density of plastics?

Thanks

The metals are usually given in vials in grains or very small beads, so I don't think you can conduct a scratch test. In my experience I've never had to do one, nor was able to.

As for the liquids, it usually varies between each proctor. But usually they'll stick to the common liquids: water, NaCl (Varying concentrations), 46% isopropyl alcohol, and vegetable oils.

It's always good to expand, but I don't think you'll need anything other than those I stated. You can distinguish all of the plastics with just those 4.