Crime Busters B

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aim4me26
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Re: Crime Busters B

Postby aim4me26 » October 6th, 2012, 3:39 pm

You have to obtain some. Animal is easy; it's just human, dog, and cat or something, right? Far as the others, ask friends and others on your team. Plenty of older ladies have X, Y, and Z fabrics lying around. Have a list of what, specifically, you need, and go asking people.
And if you mean distinguishing between them, there's a figure somewhere...you have to use a microscope. I'd almost shrink it down and drop it on your cheat sheet until (if) it becomes second nature to you.
This is a good idea; so yeah, if you already have prepared slides, they would be a good idea to look at, as well. Before the competition, my partner and I looked at dog, cat, and human hair labs. I noticed that the cat hairs are very, very, thin, whereas the dog hair is way thicker. But, the human hair appears to be VERY thick. Try this yourself, and you'll see for yourself. As for the rest, you may want to do what Skink suggested; I'm sure that will help prepare you.
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cupcakegirl
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Re: Crime Busters B

Postby cupcakegirl » October 8th, 2012, 3:49 pm

I'm looking to buy some more pH paper, but no one on the team seems to remember where we got the last batch from.

So where have you guys found good pH paper?
2013 Nationals Results: Water Quality-2nd, Food Science-6th, Crime Busters-13th, Team- 7th
2014 National Results: Water Quality- 7th, Can't Judge A Powder- 6th, Crime Busters- 4th, Heredity- 5th, Team- FIRST!!!
2015 Events: Forensics, Green Generation, Fossils

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Re: Crime Busters B

Postby retired1 » October 8th, 2012, 7:21 pm

I'm looking to buy some more pH paper, but no one on the team seems to remember where we got the last batch from.

So where have you guys found good pH paper?
If you really liked it and still have the container, google it.

Companies like hydrion sell all kinds of ph paper. I personally do not care for theirs. I do not like any paper that comes in a roll as you can contaminate it very easily. Open a new package for each competition.

If you want accuracy, you need narrow range papers, but this means that you will need more than one range. For the most accurate reading I like to lay it on a clean piece of white plastic within a few seconds and immediately compare it to the colors on the chart.

Check with all of the science teachers to see what they have rat holed away.

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aim4me26
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Re: Crime Busters B

Postby aim4me26 » October 8th, 2012, 10:39 pm

Check with all of the science teachers to see what they have rat holed away.
That's mainly what we did; we had a ton of random pH paper left over from previous years of CB, so we just used that. It should be fine, but if you can't find any, yeah, I would google it. However, the science teachers should have at least some pH paper.

Also, I googled where to get pH paper, and supposedly sometimes local fishstores/aquatic stores sell it, but don't take my word for it. So, you might want to check that out, but I doubt that there'll be some there. Also, you can always buy some online on Amazon, etc.
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Re: Crime Busters B

Postby theriddler » October 26th, 2012, 6:49 pm

Will pH paper be provided? Will HCl be provided? One common way to identify the substances is with its reaction to HCl. Or should I not use this tactic since it is time consuming?
"A man can fail many times but he isn't a failure until he begins to blame somebody else"-John Burroughs

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Re: Crime Busters B

Postby cupcakegirl » October 26th, 2012, 7:09 pm

Will pH paper be provided? Will HCl be provided? One common way to identify the substances is with its reaction to HCl. Or should I not use this tactic since it is time consuming?
You definitely need to bring your own pH paper. The proctor will provide HCl. It's all in the rules. Read them.
As for your other question, all I can really say is that it is a matter of personal preference, skill, and confidence. Do what works for you. Find the method that works for you. If that involves HCl, great. If not, great. But from experience, I can tell you that it is a bad idea to expect to be able to identify all the powders on sight... So do come up with some method. Remember that powders are usually worth roughly 30-40% of your score, so a time consuming method that works is better than a quick one that does not.
2013 Nationals Results: Water Quality-2nd, Food Science-6th, Crime Busters-13th, Team- 7th
2014 National Results: Water Quality- 7th, Can't Judge A Powder- 6th, Crime Busters- 4th, Heredity- 5th, Team- FIRST!!!
2015 Events: Forensics, Green Generation, Fossils

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Re: Crime Busters B

Postby aim4me26 » October 26th, 2012, 7:23 pm

Will pH paper be provided? Will HCl be provided? One common way to identify the substances is with its reaction to HCl. Or should I not use this tactic since it is time consuming?
You definitely have to bring your own ph paper. If you don't bring it, you're pretty much screwed. However, if this does happen to you at the competition, as a last resort, you may want to ask one of the other teams for some. They might give you some; but knowing how competitive SciOly is, I wouldn't count on it.

As for the technique, you may want to do that, but, like cupcakegirl said, it honestly depends on how quickly you can test. Do whatever you you need to do get done quickly. Also, just some random tip, you might want to also have your partner test as the same time as you. Last competition, I noticed that some people's partners were doing nothing more that just sitting down, and taking notes. Use your partner, and this process of testing will go way quicker.
i know that i should be in bed
and its almost 3 am
but when i close my eyes i can only see miles of headlights
fleshing out the distance

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Re: Crime Busters B

Postby Skink » October 26th, 2012, 8:58 pm

Personally, I find it helpful to shrink down the flow charts to barely legible level (should become second nature over time) on your cheat sheet and follow them. As long as you perform the tests correctly and know what to look for, you should be fine every time for the most part. IDing all of the powders by themselves is usually enough to 'get by' with a Regional medal.

To cupcakegirl's response, I'd like to remind you the rules list at each competition level how many mixtures you can have. Mixtures are not as readily identifiable by any one means. In fact, even the flow chart begins to become unreliable unless you're careful.
To aim4me's, if I were you, I'd have one partner work on powder ID while the other one starts the chromatography. After that, the other partner is best doing two things: A)weighing in on what the first partner is doing and B)working on the other junk(fingerprints, DNA, etc.).

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Re: Crime Busters B

Postby aim4me26 » October 27th, 2012, 10:09 pm

Yeah, I believe that the strategy that you should go with is what Skink suggested.

Last competition, neither my partner or I studied for Crime Busters, (we were focusing on other events) and when we got to regionals, we actually got 8th place, which isn't too bad, considering that we did nothing to prepare. If we had prepared, though, we could have easily medaled.

Anyway, we had basically identified all of the powders, and done the chromatography, fingerprints, etc. Our problems, though, were that we missed a few liquids, and we didn't really write a through essay. So yeah, basically just get the powders, and as much as the other stuff done as you can, and even though there's a change that you won't medal, you'll do fine. (Although I don't suggest not studying like we did... xD..)

Anyway, make sure that you leave as much time as possible for your 'essay' and cleaning up, etc.
i know that i should be in bed
and its almost 3 am
but when i close my eyes i can only see miles of headlights
fleshing out the distance

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Re: Crime Busters B

Postby theriddler » November 15th, 2012, 8:22 pm

How would you find the Ph of a solid (like powders and metals?)
"A man can fail many times but he isn't a failure until he begins to blame somebody else"-John Burroughs


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