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Can anyone help me with the two powders that are supposed to form precipitates w/ NaOH?
Calcium nitrate and magnesium sulfate? I think I have really bad samples at school or something, because neither of them are forming precipitates.
And how do you tell the difference between the two if you don't have a flame test? Do they react differently with the reagents given or have different pH? Or do the precipitates look different?
Sorry it's a lot of questions! I'll be really glad if anyone with Forensics experience can help out

poparteeb2 wrote:Can anyone help me with the two powders that are supposed to form precipitates w/ NaOH?
Calcium nitrate and magnesium sulfate? I think I have really bad samples at school or something, because neither of them are forming precipitates.
And how do you tell the difference between the two if you don't have a flame test? Do they react differently with the reagents given or have different pH? Or do the precipitates look different?
Sorry it's a lot of questions! I'll be really glad if anyone with Forensics experience can help out

Hmmm ... well not all forms of any of the powders are the same ... so that could be a factor. Also, Ca(NO3) has an orange flame test that gives off sparks, unlike MgSO4 that does not burn, but may give off water vapor.

As for distinguishing powders, I've found that pH helps quite often, and maybe conductivity or flame tests. Then there's everything else as well.

Does anyone know what the most commonly used density solutions (for plastic ID) are?

computergeek3 wrote:Does anyone know what the most commonly used density solutions (for plastic ID) are?

Check out the wiki page for Forensics. http://scioly.org/wiki/index.php/Forensics#Polymers

Common liquids used to test plastic densities include water, vegetable oil, isopropyl alcohol, and NaCl solution (10%, 25%, and saturated).

I was wondering how one would do hair follicle analysis because we had it in states last year and my teammate and I didn't know how to find out which organism it belonged to. I'm trying to cover all my bases so I will be able to avoid being dumbfounded during the event. Last year went well, but really want to make a place for my High School this year.

Skyrenify wrote:I was wondering how one would do hair follicle analysis because we had it in states last year and my teammate and I didn't know how to find out which organism it belonged to. I'm trying to cover all my bases so I will be able to avoid being dumbfounded during the event. Last year went well, but really want to make a place for my High School this year.

The two major features for hair ID are the medulla and cuticle pattern.

Human hair has a thin and often non-continuous medulla and an imbricate cuticle pattern.
Dog hair has a thick medulla and an imbricate scale pattern.
Cat hair has spinous cuticle pattern.
Bat hair has a coronal cuticle pattern.

If you don't know what any of these terms mean, they should be easily Google-able.

JustDroobles wrote:

Skyrenify wrote:I was wondering how one would do hair follicle analysis because we had it in states last year and my teammate and I didn't know how to find out which organism it belonged to. I'm trying to cover all my bases so I will be able to avoid being dumbfounded during the event. Last year went well, but really want to make a place for my High School this year.

The two major features for hair ID are the medulla and cuticle pattern.

Human hair has a thin and often non-continuous medulla and an imbricate cuticle pattern.
Dog hair has a thick medulla and an imbricate scale pattern.
Cat hair has spinous cuticle pattern.
Bat hair has a coronal cuticle pattern.

If you don't know what any of these terms mean, they should be easily Google-able.

Ahh thank you!

Might be able to get that elusive 1st place this year.
Still beating myself up for mixing up common blood types last year at states. Got us 4th place T^T

Anyhow, thank you very much

Skyrenify wrote:

JustDroobles wrote:

Skyrenify wrote:I was wondering how one would do hair follicle analysis because we had it in states last year and my teammate and I didn't know how to find out which organism it belonged to. I'm trying to cover all my bases so I will be able to avoid being dumbfounded during the event. Last year went well, but really want to make a place for my High School this year.

The two major features for hair ID are the medulla and cuticle pattern.

Human hair has a thin and often non-continuous medulla and an imbricate cuticle pattern.
Dog hair has a thick medulla and an imbricate scale pattern.
Cat hair has spinous cuticle pattern.
Bat hair has a coronal cuticle pattern.

If you don't know what any of these terms mean, they should be easily Google-able.

Ahh thank you!

Might be able to get that elusive 1st place this year.
Still beating myself up for mixing up common blood types last year at states. Got us 4th place T^T

Anyhow, thank you very much

No problem! And I know how you feel, I got 2nd place in Forensics my junior and senior year... I was actually super excited junior year because the highest placing I had gotten throughout the season was a 4th place at an invitational. However, after getting several invitational golds my senior year I was hoping for that tiny improvement at state. I hope you get that elusive gold this year!

JustDroobles wrote: No problem! And I know how you feel, I got 2nd place in Forensics my junior and senior year... I was actually super excited junior year because the highest placing I had gotten throughout the season was a 4th place at an invitational. However, after getting several invitational golds my senior year I was hoping for that tiny improvement at state. I hope you get that elusive gold this year!

Haha thanks!

I'm really good at winging things :p
For example, I made my Boomilever the day before the competition (regionals were 1 day ago) using a bansaw and some gorilla glue and 5 sticks of balsa. Somehow, every other star team broke a parameter and I got hold of 2nd.
I did Forensics in states last year as a freshman and it was traumatic. There was a pile of samples that I couldn't even fathom to identify in the allotted time. Some how I managed to place but it cost me my nose as I sniffed all the substances. (ammonia).
I really want to get rid of relying on luck and do something with real preparation.

Also, another quick question,
Can we have handwritten notes on the note sheet that we can bring?

Is the formula for Benedicts Reagent CuSO4+NaOH or CuSO4+5H2O? sorry I've seen both and idk which one is correct or if neither is correct ...