Forensics C

User avatar
SilverBreeze
Exalted Member
Exalted Member
Posts: 306
Joined: Thu Nov 28, 2019 3:42 pm
Division: C
State: CA
Has thanked: 156 times
Been thanked: 289 times

Re: Forensics C

Post by SilverBreeze »

Jonak wrote: I did the flame test with the lights off. I previously read that sodium contamination was a thing so I was looking out for that, but I never got a yellow flame, even with sodium bicarbonate and sodium carbonate. With just water the flame was orange which I was previously told it was from the nichrome wire? I've also tried potassium chloride with no success. Can we use wooden splints to do the flame test? The rules say "Flame loop" but how specific is that?
Orange... Is your water hard? That reminds me of the calcium flame a bit. Check with your tournament director or proctor about wooden splints, but there's no logical reason to prohibit them. Try to stick with a flame loop, just to avoid headaches. Try switching flame loops? Maybe it's the loop itself? Is the orange color obscuring the compound colors?

I don't really know at this point, but maybe the temperature is too high or too low? Try adjusting them using the air holes at the bottom of the burner, if you're using the same kind I am. There are some videos online for flame tests, so maybe watch them and see where your lab technique is different, and try adjusting that?
Troy SciOly 2019 - 2023
Captain 2021-2023
Former Events: Ecology, Water Quality, Green Gen, Ornithology, Forestry, Disease Detectives, Forensics, Chem Lab, Env Chem, Sounds, Dynamic Planet, Crime Busters, Potions & Poisons, Exp Design, Towers, Mystery Arch, Reach for the Stars, Mission Possible
Jonak
Member
Member
Posts: 4
Joined: Thu Dec 19, 2019 5:56 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Forensics C

Post by Jonak »

SilverBreeze wrote:
Jonak wrote: I did the flame test with the lights off. I previously read that sodium contamination was a thing so I was looking out for that, but I never got a yellow flame, even with sodium bicarbonate and sodium carbonate. With just water the flame was orange which I was previously told it was from the nichrome wire? I've also tried potassium chloride with no success. Can we use wooden splints to do the flame test? The rules say "Flame loop" but how specific is that?
Orange... Is your water hard? That reminds me of the calcium flame a bit. Check with your tournament director or proctor about wooden splints, but there's no logical reason to prohibit them. Try to stick with a flame loop, just to avoid headaches. Try switching flame loops? Maybe it's the loop itself? Is the orange color obscuring the compound colors?

I don't really know at this point, but maybe the temperature is too high or too low? Try adjusting them using the air holes at the bottom of the burner, if you're using the same kind I am. There are some videos online for flame tests, so maybe watch them and see where your lab technique is different, and try adjusting that?
I was using distilled water so that shouldn’t have been the case? I was using distilled water to wash too. I’m thinking you’re right and it was either too hot or not hot enough, I didn't play too much with the air holes though so maybe I can try that next.
TheRarePinkSheep
Member
Member
Posts: 7
Joined: Mon Feb 27, 2017 3:58 pm
Division: C
State: NY
Has thanked: 0
Been thanked: 0

Re: Forensics C

Post by TheRarePinkSheep »

Hello! I was scrolling through the forums and someone said not to dip directly into the chlorides, why exactly? I've had no problems directly dipping into the powders with a wet flame loop. Does it affect the results?

Also I've found difficulty with getting the potassium flame. I don't know whether it is because of sodium contamination or a poor flame, though a result does show up. Rather than the classic lilac flame, it is more of a peachy yellow that's not the glaring yellow of potassium.
2016-17: Crimebusters / Food Science / Meteorology
2017-18: Experimental Design / Material Science / Microbe Mission
2018-19: Boomilever / Forensics / Protein Modeling
2019-20: Boomilever / Detector Building / Forensics / Sounds of Music
User avatar
SilverBreeze
Exalted Member
Exalted Member
Posts: 306
Joined: Thu Nov 28, 2019 3:42 pm
Division: C
State: CA
Has thanked: 156 times
Been thanked: 289 times

Re: Forensics C

Post by SilverBreeze »

TheRarePinkSheep wrote: Wed Jan 01, 2020 9:00 am Hello! I was scrolling through the forums and someone said not to dip directly into the chlorides, why exactly? I've had no problems directly dipping into the powders with a wet flame loop. Does it affect the results?

Also I've found difficulty with getting the potassium flame. I don't know whether it is because of sodium contamination or a poor flame, though a result does show up. Rather than the classic lilac flame, it is more of a peachy yellow that's not the glaring yellow of potassium.
Ah, that would be me. For me, the solution tends to be too concentrated and dry onto the flame loop. It's hard for me to get off and contaminates future results, especially since I practice with an alcohol lamp, which has a lower temperature than a bunsen burner. That means I can't check whether all of the powder came off until it's too late(as I found out the hard way). The test itself turns out fine, and if it works for you, keep doing it.

There might be slight sodium contamination, but not enough to block out the potassium. Also, for me, the flame doesn't turn up a vivid lilac, but more a faint lilac with a lot of yellow and orange mixed in. There are videos of flame tests on YouTube, I believe, and watching those might help you determine if that's just the way you perceive the flame. It might also be your lighting, and you can try turning off the lights when practicing.
Troy SciOly 2019 - 2023
Captain 2021-2023
Former Events: Ecology, Water Quality, Green Gen, Ornithology, Forestry, Disease Detectives, Forensics, Chem Lab, Env Chem, Sounds, Dynamic Planet, Crime Busters, Potions & Poisons, Exp Design, Towers, Mystery Arch, Reach for the Stars, Mission Possible
WangwithaTang
Member
Member
Posts: 111
Joined: Thu Jan 03, 2019 8:48 pm
Has thanked: 5 times
Been thanked: 3 times

Re: Forensics C

Post by WangwithaTang »

How would you guys recommend studying for plastics?
User avatar
Limke
Member
Member
Posts: 21
Joined: Wed Feb 28, 2018 5:47 pm
Division: C
State: PA
Has thanked: 0
Been thanked: 0

Re: Forensics C

Post by Limke »

WangwithaTang wrote: Tue Jan 28, 2020 4:32 pm How would you guys recommend studying for plastics?
I would recommend repetitive practice with density solutions. Test each plastic (knowing what it is) in each solution to see what happens and take notes. After you've gotten a "feel" for the behavior of each plastic in different solutions (floating or sinking), I would just keep doing random practice tests with unknown samples and then check your answers. Whenever you get one wrong, just retest it.

Also, if possible (with the supervision of a teacher/coach, a fume hood, and other appropriate safety equipment), it may be helpful to burn the plastics (knowing what they are) so you can take notes on their behavior and observe what they do. Not all event supervisors will burn plastics, but I know my state event supervisor typically does.

With all physical evidence (fibers/powders/plastics), you are limited to what samples you can be tested on. Constant repetition and being familiar with the behavior of your samples is the best way to correctly ID them each time.
2019 Events: Anatomy & Physiology, Designer Genes, Forensics, Protein Modeling.

2020 Events: Anatomy & Physiology, Protein Modeling, Forensics, Sounds of Music

do not eat the forensics powders
RavidD
Member
Member
Posts: 3
Joined: Fri Nov 15, 2019 6:51 am
State: PA
Has thanked: 0
Been thanked: 0

Re: Forensics C

Post by RavidD »

Any recommendations for metal shavings? For some reason it's one of the only ones giving me trouble.
User avatar
CPScienceDude
Exalted Member
Exalted Member
Posts: 371
Joined: Wed Dec 12, 2018 2:40 pm
Division: C
State: IN
Pronouns: He/Him/His
Has thanked: 144 times
Been thanked: 89 times

Re: Forensics C

Post by CPScienceDude »

RavidD wrote: Mon Feb 10, 2020 11:03 am Any recommendations for metal shavings? For some reason it's one of the only ones giving me trouble.
There are no metal shavings in Forensics. If you're in Crime Busters, though, here is a good resource: http://mypage.iu.edu/~lwoz/socrime/metanal.htm
Captain of CPSO

Assassinator 139 and 147
2023 events: Chem Lab, Experimental Design, It's About Time, Scrambler, Trajectory

About Me!
Image
User avatar
jaspattack
Moderator
Moderator
Posts: 123
Joined: Mon Apr 30, 2018 8:29 am
Division: Grad
State: MO
Has thanked: 139 times
Been thanked: 140 times

Re: Forensics C

Post by jaspattack »

Since the rules say one note sheet per participant you can have two sheets front and back total for this event, correct? I'm working on mine for regionals and while my key for powders isn't done yet, I don't see myself needing to use the whole four pages...
CHS '21 // Mizzou '25 | Jaspattack's Userpage

2020-21 Events: Designer Genes, Forensics, Ornithology, Protein Modeling

I edit the wiki sometimes.
User avatar
CPScienceDude
Exalted Member
Exalted Member
Posts: 371
Joined: Wed Dec 12, 2018 2:40 pm
Division: C
State: IN
Pronouns: He/Him/His
Has thanked: 144 times
Been thanked: 89 times

Re: Forensics C

Post by CPScienceDude »

jaspattack wrote: Tue Feb 11, 2020 1:21 pm Since the rules say one note sheet per participant you can have two sheets front and back total for this event, correct? I'm working on mine for regionals and while my key for powders isn't done yet, I don't see myself needing to use the whole four pages...
If you’re soloing, then you only get one page. If you have a partner, then yes, you get 2 front and back pages.
Captain of CPSO

Assassinator 139 and 147
2023 events: Chem Lab, Experimental Design, It's About Time, Scrambler, Trajectory

About Me!
Image

Return to “2020 Lab Events”