Forensics C

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Re: Forensics C

Postby pikachu4919 » October 16th, 2018, 1:43 pm

Anomaly wrote:
pikachu4919 wrote:
Unome wrote:Ask any of your friends that do A&P :P


Ye, small fonts, really wide margins, but one thing about 4n6 is that although there are so many different topics, you don't necessarily need to put them all on your cheat sheet (i.e. tracks, striations) depending on how much you know about them - for example, if you do lots of biology and/or also happen to do designer genes, you may not necessarily need to include any cheat sheet info on DNA or blood typing.

Making your cheatsheet is really a careful process of making the most out of the space you have in the area. If there's something you're confident you know by heart, then there's no need to put it on your sheet, and that frees up that space for you to put something else that you're maybe not as confident with. But that's up to you and what you know.

Wait why wide margins?


I guess I meant narrow, lol. I was thinking more along the lines of widening the space on the page, hehe. Oops.
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Re: Forensics C

Postby mrcb03 » November 3rd, 2018, 9:44 pm

Person wrote:
pikachu4919 wrote:
nicholasmaurer wrote:
Yes.


What’s weird tho is that in the next line of rule 2.b. it says “This sheet” instead of something like “these sheets.” I guess if you interpret the rule before as each team member bringing a sheet, then it should still be two sheets, not one.

Disclaimer: this is my own opinion and may not reflect what SO, inc. actually intended with their wording. If this is something you want to clear up with them, submit an FAQ or Rule Clarification on soinc.org.

I assume they worded it that way because the previous sentence only referred to a single participant's sheet, and there could technically be just one team member competing.


They clarified this rule; yes each participant may have one sheet of paper each. Therefore giving the team 2 sheets total :D

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Re: Forensics C

Postby mrcb03 » November 3rd, 2018, 9:49 pm

Would anyone be willing to share what they have in terms of pH's for qualitative analysis?

Also what are we supposed to base plastic identifications on? Only two of the forensics labs I've done had plastics, and neither of them provided the same thing (they ended up cancelling the plastics portion at one of them anyway because it was incorrect or unreasonable).

Thanks!

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Re: Forensics C

Postby pikachu4919 » November 7th, 2018, 8:53 am

mrcb03 wrote:Would anyone be willing to share what they have in terms of pH's for qualitative analysis?

Also what are we supposed to base plastic identifications on? Only two of the forensics labs I've done had plastics, and neither of them provided the same thing (they ended up cancelling the plastics portion at one of them anyway because it was incorrect or unreasonable).

Thanks!


pH: the most crucial ones you should remember are that sodium carbonate has a really high pH (should be around 10) and boric acid has a really low pH (usually around 4 or less). Everything else is within a range of a pH of 5-8, which, depending on your litmus/pH paper, may show very similar colors. It may also be important to know that sodium acetate's pH is around 8 in case you need that information to differentiate it from the rest of the sodium compounds.

Plastics: Those should generally be based on density, in which your supervisor, if they put plastics on their test, theoretically should give you a series of solutions with varying densities to help you differentiate those (if they're doing their job correctly). From there on out it's mostly float/sink tests, and if it's pertinent, you may be provided with burn test results, in which the most crucial thing to remember is that PVC will give off a green flame when burned.
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Re: Forensics C

Postby adriandsouza5404 » November 22nd, 2018, 6:35 am

In rule f.i., it says "Students may be asked questions on the different methods of detecting fingerprints and the chemistry behind each of these methods." Is detecting fingerprints the same thing as fingerprint development techniques like powers, and ninhydrin fuming?
Last edited by pikachu4919 on November 22nd, 2018, 10:08 am, edited 1 time in total.
Reason: Please use proper methods for citing rules

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Re: Forensics C

Postby pikachu4919 » November 22nd, 2018, 10:15 am

adriandsouza5404 wrote:In rule f.i., it says "Students may be asked questions on the different methods of detecting fingerprints and the chemistry behind each of these methods." Is detecting fingerprints the same thing as fingerprint development techniques like powers, and ninhydrin fuming?


Yes, that is correct. If you wanted to get really technical, you could say that this rule could also include different kinds of lighting or filtering techniques (i.e. using a blacklight, or a filter for a different wavelength of light) that are used to find fingerprints before you develop them, but an explanation for why it's something that's rarely tested is potentially because it could maybe be beyond the current Chemistry Committee's scope of expertise. I wouldn't know for sure, since I'm not on that committee, but ...it's plausible, based on those I know that are on it.
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Re: Forensics C

Postby Panda Weasley » November 29th, 2018, 5:20 pm

I have never used conductivity as a way to distinguish powders simply because I previously haven't had access to reliable conductivity testers. Is it worth learning this test now? Do y'all find it helpful?

Also, I'm just curious what y'alls first step for powder ID is? I enjoy seeing how people approach IDing differently.
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Re: Forensics C

Postby scienceisfunalil » December 3rd, 2018, 4:27 am

Does chromatography using coffee filters fall under the rules? The rules say paper and TLC.
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Re: Forensics C

Postby pikachu4919 » December 3rd, 2018, 8:41 am

Panda Weasley wrote:I have never used conductivity as a way to distinguish powders simply because I previously haven't had access to reliable conductivity testers. Is it worth learning this test now? Do y'all find it helpful?

Also, I'm just curious what y'alls first step for powder ID is? I enjoy seeing how people approach IDing differently.


1. It's mostly helpful for ionic compounds, not necessarily much else. Even so, that's a pretty broad category, so it's not extremely distinguishing. A lot of people tend to get confused by conductivity testers that always light up if they think that stuff that's not super conductive won't light up at all, but in reality, anything will light up since there are always a handful of ions floating around even in DI water, but the key is in the brightness of the light - conductive materials will cause it to shine very brightly and vice versa for not conductive materials.

2. flame test

scienceisfunalil wrote:Does chromatography using coffee filters fall under the rules? The rules say paper and TLC.


I mean, coffee filters are made of paper...
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Re: Forensics C

Postby kitkathw871 » December 6th, 2018, 1:27 pm

mrcb03 wrote:
Person wrote:
pikachu4919 wrote:
What’s weird tho is that in the next line of rule 2.b. it says “This sheet” instead of something like “these sheets.” I guess if you interpret the rule before as each team member bringing a sheet, then it should still be two sheets, not one.

Disclaimer: this is my own opinion and may not reflect what SO, inc. actually intended with their wording. If this is something you want to clear up with them, submit an FAQ or Rule Clarification on soinc.org.

I assume they worded it that way because the previous sentence only referred to a single participant's sheet, and there could technically be just one team member competing.


They clarified this rule; yes each participant may have one sheet of paper each. Therefore giving the team 2 sheets total :D


Can someone link where the clarification comes from? Thanks!

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Re: Forensics C

Postby pikachu4919 » December 6th, 2018, 3:49 pm

kitkathw871 wrote:
mrcb03 wrote:
Person wrote:I assume they worded it that way because the previous sentence only referred to a single participant's sheet, and there could technically be just one team member competing.


They clarified this rule; yes each participant may have one sheet of paper each. Therefore giving the team 2 sheets total :D


Can someone link where the clarification comes from? Thanks!


Click here (the URL is absurdly long)
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Re: Forensics C

Postby Qu€€nMon€y » December 12th, 2018, 6:22 pm

I need help with reading a mass spec graph. I do not understand how to find the mass of the substance or the identity of the substance. Can someone send me helpful links?

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Re: Forensics C

Postby Calico4243 » December 13th, 2018, 1:19 pm

Hello! I'm new to the forensics event for scioly. I was wondering if anyone knows where I could find study materials. Particularly for qualitative analysis, polymers, chromatography, mass spectrometry, and DNA.

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Re: Forensics C

Postby pikachu4919 » Yesterday, 5:11 pm

Qu€€nMon€y wrote:I need help with reading a mass spec graph. I do not understand how to find the mass of the substance or the identity of the substance. Can someone send me helpful links?


http://ochem.com/tutorials/mass-spectro ... 3-min.html - This is a pretty solid 30-ish-min video tutorial on many things you need to know about mass spec, but in short, the mass of the substance is typically the final peak at the very end and will normally be labeled as "M+" and finding the identity of the substance requires much more work, depending on how much additional information is given beyond the mass spec result itself. These could range from knowing the specific peaks that specific potential parts of a molecule (such as a hydroxyl group, a carbonyl group, or a benzyl group) will result in to knowing how fragmentation works - basically molecules get broken up as they travel through the mass spec machine, they break into fragments of all sorts of sizes, think of the possible resulting fragments from that molecule, then figure out where they may show up on the mass spec. These are just simplified explanations of some of the concepts, and I would suggest reading a section on this in an organic chemistry textbook or online resource for more in-depth information.

Calico4243 wrote:Hello! I'm new to the forensics event for scioly. I was wondering if anyone knows where I could find study materials. Particularly for qualitative analysis, polymers, chromatography, mass spectrometry, and DNA.


The Forensics Wiki is a good starting point, and the national supervisor has her own personal website with many resources here. Those can at least get you started, but I cannot emphasize enough that your biggest friend in prepping for this event would be actually practicing the lab portion. You can read all about how different tests are supposed to turn out, but observing them yourself will solidify your understanding of them.
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