Forensics C

LostInTheSauce
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Re: Forensics C

Postby LostInTheSauce » February 3rd, 2019, 3:15 pm

Does anyone have some advice on how to identify a given plastic sample?

(no burn tests permitted, no solutions of different densities or indices provided)
Guessing you went to the Solon Invitational?

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jimmy-bond
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Re: Forensics C

Postby jimmy-bond » February 3rd, 2019, 3:43 pm

Does anyone have some advice on how to identify a given plastic sample?

(no burn tests permitted, no solutions of different densities or indices provided)
I have notes on how transparent the plastics are but that's about it. It's hard to differentiate between the opaque plastics because they all look the same, so I have no clue how the testmakers intended for it to be done.
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Re: Forensics C

Postby c21k » February 3rd, 2019, 7:30 pm

Does anyone have some advice on how to identify a given plastic sample?

(no burn tests permitted, no solutions of different densities or indices provided)
Guessing you went to the Solon Invitational?
Haha, yep! I was so lost on the plastics... :cry:
I have notes on how transparent the plastics are but that's about it. It's hard to differentiate between the opaque plastics because they all look the same, so I have no clue how the testmakers intended for it to be done.
hmmm yeah, that's what I'm trying to figure out right now
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Re: Forensics C

Postby olhs4n6 » February 3rd, 2019, 7:53 pm

Does anyone have some advice on how to identify a given plastic sample?

(no burn tests permitted, no solutions of different densities or indices provided)
Guessing you went to the Solon Invitational?

The Solon Invitational forensics was absolutely insane. My partner's first time doing it, so I had her literally just read and make lists of the suspects/what would implicate them. That alone took her 10 minutes (but she did find a bonus at the end of the instructions). We were lost at what to do with the plastics so I just put them in water and guessed from there... yikes... At least we got the person right. Any tips for how to divide/conquer better at regionals?

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Re: Forensics C

Postby c21k » February 3rd, 2019, 8:05 pm

Does anyone have some advice on how to identify a given plastic sample?

(no burn tests permitted, no solutions of different densities or indices provided)
Guessing you went to the Solon Invitational?

The Solon Invitational forensics was absolutely insane. My partner's first time doing it, so I had her literally just read and make lists of the suspects/what would implicate them. That alone took her 10 minutes (but she did find a bonus at the end of the instructions). We were lost at what to do with the plastics so I just put them in water and guessed from there... yikes... At least we got the person right. Any tips for how to divide/conquer better at regionals?
Wow, what a way to start! Props to your partner for surviving it and living to tell the tale ;) For the division of material, my partner and I split the qualitative analysis. Then we assign other material based on our strengths. The leftovers we both study so that whoever finishes their section of the test can just do those parts. I also find that allotting time for specific areas of the test can be helpful for pacing purposes.
Forensics 3/4, Sounds 1/2, Fossils 2/8, MP 2/6, Mouse 1/7
R&M, Optics, XPD, WIDI, Dynamic, GeoMapp, (filler - IAT, Towers)

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Re: Forensics C

Postby pikachu4919 » February 3rd, 2019, 8:36 pm


Guessing you went to the Solon Invitational?

The Solon Invitational forensics was absolutely insane. My partner's first time doing it, so I had her literally just read and make lists of the suspects/what would implicate them. That alone took her 10 minutes (but she did find a bonus at the end of the instructions). We were lost at what to do with the plastics so I just put them in water and guessed from there... yikes... At least we got the person right. Any tips for how to divide/conquer better at regionals?
Wow, what a way to start! Props to your partner for surviving it and living to tell the tale ;) For the division of material, my partner and I split the qualitative analysis. Then we assign other material based on our strengths. The leftovers we both study so that whoever finishes their section of the test can just do those parts. I also find that allotting time for specific areas of the test can be helpful for pacing purposes.
Hi um, I was one of the three writers of that test, and unfortunately, none of us were actually able to be there to proctor it. Now that I think about it, I realize we forgot to tell the person who was proctoring it (who was doing so for the first time ever) to make those density solutions. That's our fault, and we thoroughly apologize for it.

As for tackling the test, that test is actually a baby version of the one that my co-ES at MIT and I wrote for the 2019 MIT Invite (he was also one of the other two writers), and I'll say that the way you split is entirely dependent on what you and your partner each are comfortable with. For example, if someone can do powders really well and can't do polymers while the other person can do polymers really well yet can't do powders very well, then you can obviously definitely split that way. Or if one person is super comfortable with both parts of ID while one person doesn't, then you can have that person do all ID's and then the other person focuses solely on the crime/free response. Again, I can't comment on any one pair's synergy, so that's up to you to decide. But total trust in your partner is a must - if you want to finish the test, you absolutely will not have time to check over your partner's work, and you have to trust that they knew what they were doing. Some things for sure are that I would advise starting the chromatography right when the time starts and leaving ~20mins solely for the crime analysis, and at that time, your partner can either finish the rest of the ID's and/or tackle the free response and not start cleanup until 5 mins before time. That's how I would ideally approach it, but it does take quite a bit of skill to pull it off.

If this says anything, a couple lucky competitors got to start their forensics careers with my other partial brainchild in the 2019 MIT Forensics test...
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Re: Forensics C

Postby Qu€€nMon€y » February 7th, 2019, 4:09 pm

Does anyone have some advice on how to identify a given plastic sample?

(no burn tests permitted, no solutions of different densities or indices provided)
Guessing you went to the Solon Invitational?

The Solon Invitational forensics was absolutely insane. My partner's first time doing it, so I had her literally just read and make lists of the suspects/what would implicate them. That alone took her 10 minutes (but she did find a bonus at the end of the instructions). We were lost at what to do with the plastics so I just put them in water and guessed from there... yikes... At least we got the person right. Any tips for how to divide/conquer better at regionals?

Wait one question: How did you differentiate the plastics with water? When I practiced the plastics, all the plastics floated. Does anyone have notes on plastics that could be useful?
Medal count: 1 :(

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Re: Forensics C

Postby olhs4n6 » February 7th, 2019, 4:22 pm


Guessing you went to the Solon Invitational?

The Solon Invitational forensics was absolutely insane. My partner's first time doing it, so I had her literally just read and make lists of the suspects/what would implicate them. That alone took her 10 minutes (but she did find a bonus at the end of the instructions). We were lost at what to do with the plastics so I just put them in water and guessed from there... yikes... At least we got the person right. Any tips for how to divide/conquer better at regionals?

Wait one question: How did you differentiate the plastics with water? When I practiced the plastics, all the plastics floated. Does anyone have notes on plastics that could be useful?
You would usually need more than one liquid (corn oil, isopropyl alcohol, water, salt-water, etc) to be able to differentiate solely based on density. I would practice plastics again, only PP, LDPE, and HDPE should float in water, though I could be wrong. My plastics info just came from the wiki at https://scioly.org/wiki/index.php/Forensics (someone else can back me up on the water thing though)

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Re: Forensics C

Postby c21k » February 7th, 2019, 5:11 pm



The Solon Invitational forensics was absolutely insane. My partner's first time doing it, so I had her literally just read and make lists of the suspects/what would implicate them. That alone took her 10 minutes (but she did find a bonus at the end of the instructions). We were lost at what to do with the plastics so I just put them in water and guessed from there... yikes... At least we got the person right. Any tips for how to divide/conquer better at regionals?

Wait one question: How did you differentiate the plastics with water? When I practiced the plastics, all the plastics floated. Does anyone have notes on plastics that could be useful?
You would usually need more than one liquid (corn oil, isopropyl alcohol, water, salt-water, etc) to be able to differentiate solely based on density. I would practice plastics again, only PP, LDPE, and HDPE should float in water, though I could be wrong. My plastics info just came from the wiki at https://scioly.org/wiki/index.php/Forensics (someone else can back me up on the water thing though)
I am in concurrence with olhs4n6. The density of water is about 1 g/ml while PP, LDPE, and HDPE have densities higher than 1 g/ml. Make sure that if you do practice with water, that it is deionized/distilled water. I don't know if tap water has enough contaminants that it would alter the density that significantly, but seeing as all the plastics floated on your last trial, it wouldn't hurt.
Forensics 3/4, Sounds 1/2, Fossils 2/8, MP 2/6, Mouse 1/7
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Re: Forensics C

Postby Qu€€nMon€y » February 18th, 2019, 10:35 am

So at the cornell invitational bunsen burners didn't work so we had candles instead which I didn't understand how to ID powders without a bunsen burner. Any tips on identifying powders without flame test?
Medal count: 1 :(


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