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RosesAndPandas wrote:Idk if anyone saw my post in Microbe Mission, but are judges picky on the type of goggles used??????? I don't have the exact goggles (my school uses different ones). Am I going to be penalized or anything?

It depends on the competition. If the judges follow the rules exactly, then yes, they will be picky about the goggles, because the type of goggles is specified in the rules for each event. However, at some regional and invitational tournaments, you might get away with different goggles. From what I've seen, most state and all national judges are very particular about having the correct goggles, though.

to anyone who did Forensics last year, is it much different from last year at Regionals?

Phenylethylamine wrote:

RosesAndPandas wrote:Idk if anyone saw my post in Microbe Mission, but are judges picky on the type of goggles used??????? I don't have the exact goggles (my school uses different ones). Am I going to be penalized or anything?

It depends on the competition. If the judges follow the rules exactly, then yes, they will be picky about the goggles, because the type of goggles is specified in the rules for each event. However, at some regional and invitational tournaments, you might get away with different goggles. From what I've seen, most state and all national judges are very particular about having the correct goggles, though.

Several years ago, I was asked to run Forensics at our local regional. 10 of the 14 teams showed up with safety chemical GLASSES, not goggles. Yes, they wrapped around their face, but they did not seal tight to their face. As a matter of safety, i did not allow those teams to compete, unless they could come with the correct goggles, which cost all of them valuable time. In the end, there were not enough teams left to even fill all of the ribbon places... If I were you, I'd make sure that my GOGGLES were per spec!

After I made the mistake of accidentally writing 4 of the 5 chemicals in the wrong spot on our last Forensics test (therefore getting us no credit), my partner decided we should have a Chemical Race to decide who's doing the chem ID at Regionals. We have the same Chem teacher (I'm in honors Chem, he's older and in AP Chem), but it was really hard to get a time since he's a soccer coach. But we had our race today at lunch- we had six identical chemicals, and the challenge was to ID them all as quickly and accurately as possible. Since we share materials/HCl/NaOh/notes/whatever, we had to be at back to back lab stations which was a little awkward, but I won. We each got 5 of 6, with the same one (cornstarch) tripping us up. But I was faster, so I won. He was a little mad since he's a super-competitive individual and ahead of me in Chem, but he'll get over it. Now onto Regionals!

I've actually had a lot of fun with Chem ID. We've done some crazy stuff. Now, anyone have any tips on fibers?

courage7856 wrote:We each got 5 of 6, with the same one (cornstarch) tripping us up.

Correct me if I'm wrong, but I think cornstarch is the only powder on the list this year that changes color with KI solution... Did you not have iodine?

Phenylethylamine wrote:

courage7856 wrote:We each got 5 of 6, with the same one (cornstarch) tripping us up.

Correct me if I'm wrong, but I think cornstarch is the only powder on the list this year that changes color with KI solution... Did you not have iodine?

We did, but some of the other things didn't seem so cornstarchy. . .mine seemed purple when I burned it (I'd just cleaned my wire so it wasn't contaminated, and I haven't seem potassium chloride in a while, so I'm not sure why), so I thought it was KCl. My partner, for some reason, thought it was Ca(NO3)2, also because of flame test. I asked him to show me, but then, of course, it looked nothing like that.

courage7856 wrote:

Phenylethylamine wrote:

courage7856 wrote:We each got 5 of 6, with the same one (cornstarch) tripping us up.

Correct me if I'm wrong, but I think cornstarch is the only powder on the list this year that changes color with KI solution... Did you not have iodine?

We did, but some of the other things didn't seem so cornstarchy. . .mine seemed purple when I burned it (I'd just cleaned my wire so it wasn't contaminated, and I haven't seem potassium chloride in a while, so I'm not sure why), so I thought it was KCl. My partner, for some reason, thought it was CaNO3, also because of flame test. I asked him to show me, but then, of course, it looked nothing like that.

It can't possibly be KCl or Ca(NO3)2 because they're both soluble in water. Cornstarch is clearly insoluble, and that should keep you on the right track

Sometimes you can have problems doing iodine test with cornstarch. Make sure the concentration of cornstarch in the test tube is high enough, otherwise it may not change color. This happened to my partner during invitationals.

For the chemical test really you only need about two or three tests to narrow it down for example, flame tests, pH and one other is about enough. However, you have to be well rounded on everything, something I learned the hard way this year. Chromatography has been tested every year since I have been doing it (even during Sci. Crime Busters div. B) but, don't focus too much on the powders/ compounds find a good balance between all of the topics listed.

ribonucleicacid621 wrote:Sometimes you can have problems doing iodine test with cornstarch. Make sure the concentration of cornstarch in the test tube is high enough, otherwise it may not change color. This happened to my partner during invitationals.

If you drip Lugol's solution (KI) onto cornstarch- straight onto the powder, in a well plate or something like that, not in solution- you should definitely see it change color.