Can't Judge a Powder B

[Jim_R]

Discussion for Can't Judge a Powder B.

[2win]

so for this event, you have to be able to name powders? is that all?

[gneissisnice]

Not even that, no time in the event do you have to ID the powder.
You have to write down observations, such as physical properties of the powder (color, relative grain size, solid), and it's reactions with other chemicals (does it effervesce in HCl? or react with NaOH?).
You have to write down everything you can think of, even if it's really obvious. Then you clean up and take a test, answering questions about the powder. You get 5 points for a correct answer with an observation, and 2 points for a correct answer without an observation. You have to number each observation, and then put the number down by the question that requires it.

That's basically the event. They generally give you boring, non-reactive powders too. And no observation is too trivial for them. At nationals one year, they gave us the powder in a bag which was numbered, they asked us what number was on the bag =/

[2win]

oh, okay. thanks!

[IZhou186]

so is this a really easy and boring event that doesn't require much preparation?

[robotman]

no this is a fun event i have had the chance to do it at a Camp

and there is no science Olympiad event that is easy with the exception of pentathlon all the events you are in you need to study and work on if you wish to medal in them

[gneissisnice]

so is this a really easy and boring event that doesn't require much preparation?

Though the premise is simple, competitions can get really hard sometimes.
You need to be able to communicate well, having one person write down the observations while the other does the tests.

At nationals one year, they gave us the basic reagents (HCl, NaOH, and water), and then they gave us phenolphthalein, bromothymyl blue, and some other chemical, and we had to due all the tests within 30 minutes.
My partner and I tried to work fast, but we were halfway through phenolphthalein when the time ended, with 2 more reagents to go. Of course, nearly every question on the test was about the reaction with phenolphthalein, bromothymyl blue, and the other one.
Needless to say, we got 51st =(.
It made me sad.

You're gonna want to practice and be able to execute the tests quickly and decisively.

[Science Guava]

I was just researching this event and it seems like you should know more about how to make the right observations rather than trying to identify the powder usong these observations. Although, I'm kind of nervous about what sorts of powders that are generally used. Has anyone who's done it before got some ideas? (pardon the grammar)

[robotman]

you do not have to identify the powders there is a list of powders in the rules which are recomendations on what may be used
the only time i have doe it before was at SO camp and it really is just making as many accurate observations of the substance

i suggest learning the different ways to classify grains (size texture etc)

[Amber259]

isn't like food science

[Phenylethylamine]

From what I've heard, they also make you use two different color pens- one for the observation part, and one for the test part- so you can't add observations to the list afterwards.

[robotman]

yes that is true but the proctors get to pick the writing utensils i think

[gneissisnice]

yes that is true but the proctors get to pick the writing utensils i think

Yeah, you're not allowed to bring writing utensils to the event, if I remember correctly.
Instead, the proctors give you one color ink, then when you're done with the first part, they take the pen back and give you a different color pen.

[karatekid44]

yes that is true but the proctors get to pick the writing utensils i think

Yeah, you're not allowed to bring writing utensils to the event, if I remember correctly.
Instead, the proctors give you one color ink, then when you're done with the first part, they take the pen back and give you a different color pen.

that would make sense because then say you wrote your observations in blue and your done. You have switched to the next section you get a red pen but then you realized you missed an observation you try to go back and write it down. But the proctors will know they were done at two different times becuase of the color of the ink.

[SOninja]

This is my first time on this event and my group is just as clueless.
we're going to start by testing some crime powders with stuff like:
mass
color
luster
coarse/fine
size/shape (shape...maybe that would only apply to crystalline stuff?)
solubility with water and HCI
pH
reactions with water
reactions with HCI
reactions with iodine (should we?)
density compared to water/HCI
benedicts? (not sure about using indicators ... bromothymol blue? methyl red? biuret solution?)
uhh i'm pretty sure we're missing a lot, so suggestions are more than welcome
thanks~