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Re: Forensics C

Posted: September 26th, 2017, 6:01 pm
by WhatScience?
Why would you even want to touch the dead body of an animal?

Re: Forensics C

Posted: September 27th, 2017, 5:40 pm
by sciduck
Person wrote: You could probably find a dead squirrel somewhere to get hairs :P
We may have done that...
WhatScience? wrote:Why would you even want to touch the dead body of an animal?
Science! [Just wear gloves.]

Also, you can buy squirrel paint brushes. In my experience, the texture of brush hairs shows up better than that of roadkill.

Re: Forensics C

Posted: October 29th, 2017, 8:34 am
by raxu
What is the hot water bath used for?

@Below: Thank you!

Re: Forensics C

Posted: October 29th, 2017, 9:36 am
by pikachu4919
raxu wrote:What is the hot water bath used for?
Benedict’s solution test - indicates presence of reducing sugars, namely glucose

Re: Forensics C

Posted: October 31st, 2017, 4:55 am
by ic3kreem
How do you do this event good if you know nothing?

Re: Forensics C

Posted: October 31st, 2017, 7:00 am
by Unome
ic3kreem wrote:How do you do this event good if you know nothing?
You learn. Start by taking one area - for example, plastics - and learn the different characteristics that can be used to identify them, such as density (which you can test with solutions of varying density and whether the sample sinks or floats), flame test results (you can be given data but per the rules aren't allowed to perform flame tests during competition with plastics), etc. Repeat this with other categories of evidence like fibers, hairs, qualitative (powders). Then, move on to the rule 3.e topics, as well as things like chromatography and mass spectroscopy. If possible, find a way to practice actually performing lab tests for the 3.b and 3.c topics. Others can elaborate, since I'm not particularly familiar with this event.

Edit: Go with what pikachu says.

Re: Forensics C

Posted: October 31st, 2017, 8:40 am
by pikachu4919
Unome wrote:
ic3kreem wrote:How do you do this event good if you know nothing?
You learn. Start by taking one area - for example, plastics - and learn the different characteristics that can be used to identify them, such as density (which you can test with solutions of varying density and whether the sample sinks or floats), flame test results (you can be given data but per the rules aren't allowed to perform flame tests during competition with plastics), etc. Repeat this with other categories of evidence like fibers, hairs, qualitative (powders). Then, move on to the rule 3.e topics, as well as things like chromatography and mass spectroscopy. If possible, find a way to practice actually performing lab tests for the 3.b and 3.c topics. Others can elaborate, since I'm not particularly familiar with this event.
"You learn" - oh yeah, totally specific. Anyways.....

The scioly.org wiki, previous threads in this forum (in additional to this year's forum), soinc.org, and building a foundation in some topics in general chemistry (such as reactions, balancing equations, maybe stoich) should be great places to start learning some of the theoretical knowledge. I know Unome was just giving an example, but honestly imo Qualitative analysis is a much better place to start than plastics since it could be considered as one of the more difficult parts of Forensics, since the identification tests are much more fragile/prone to error than they are for polymers. And, as I think I've been advocating for a while, the best way to get even better is to do as much practice as you can in the lab on some of the identification tests. Observing it yourself will help immensely with remembering what a some of the key indicating tests for each powder should look like.

And also, it never hurts to ask current or previous competitors about the information! Many of them, myself included, should be open to helping you out!

Re: Forensics C

Posted: October 31st, 2017, 7:09 pm
by daydreamer0023
pikachu4919 wrote:
Unome wrote:
ic3kreem wrote:How do you do this event good if you know nothing?
You learn. Start by taking one area - for example, plastics - and learn the different characteristics that can be used to identify them, such as density (which you can test with solutions of varying density and whether the sample sinks or floats), flame test results (you can be given data but per the rules aren't allowed to perform flame tests during competition with plastics), etc. Repeat this with other categories of evidence like fibers, hairs, qualitative (powders). Then, move on to the rule 3.e topics, as well as things like chromatography and mass spectroscopy. If possible, find a way to practice actually performing lab tests for the 3.b and 3.c topics. Others can elaborate, since I'm not particularly familiar with this event.
"You learn" - oh yeah, totally specific. Anyways.....

The scioly.org wiki, previous threads in this forum (in additional to this year's forum), soinc.org, and building a foundation in some topics in general chemistry (such as reactions, balancing equations, maybe stoich) should be great places to start learning some of the theoretical knowledge. I know Unome was just giving an example, but honestly imo Qualitative analysis is a much better place to start than plastics since it could be considered as one of the more difficult parts of Forensics, since the identification tests are much more fragile/prone to error than they are for polymers. And, as I think I've been advocating for a while, the best way to get even better is to do as much practice as you can in the lab on some of the identification tests. Observing it yourself will help immensely with remembering what a some of the key indicating tests for each powder should look like.

And also, it never hurts to ask current or previous competitors about the information! Many of them, myself included, should be open to helping you out!
I would second starting w/ powders - they will also give you the most points. Practice, as pikachu4919 said, is key. Just play around with the powders on the list, see how they react and such. I wouldn't rely on flowcharts created by others or depend entirely on tables (especially for what the powder looks like) for success in this area because:
1) Powders don't always look the same, even if they have the same chemical composition
2) What others describe may not be how you will describe them

Essentially, learn how you work

Re: Forensics C

Posted: November 15th, 2017, 5:22 pm
by challis3
So this is my first year doing the event just wondering if anyone had tips for it i am currently working with my partner and have split up the work and have also done small amounts of work on each topic but not mastered a specific topic yet. :geek:

Re: Forensics C

Posted: November 17th, 2017, 4:28 pm
by rooee
Hey guys, newer member here. Just wanted to ask what sorts of powders would react with NaOH and if they do, if the dissolving process is slow or fast. Thanks!