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Nitrogen Triiodide Explosion [Photo]

A gorgeous photo of pressure sensitive nitrogen triiodide exploding at 1000 m/s is shown below.

From vastib

The photo was taken in the dark with the camera’s shutter open, and a flash triggered by a pressure sensitive detector.

Apparently this was submitted as part of a manuscript to the Journal of Chemical Education for an undergraduate lab demo measuring how fast the explosion propagates through the material. Unfortunately, it was rejected as too dangerous.

The decomposition reaction is…
$$! 8\text{NI}_3\text{NH}_3 \rightarrow 5\text{N}_2 + 6\text{NH}_4\text{I} + 9\text{I}_2$$

Chemical details on nitrogen triiodide can be found from the MOTM page contribution by Simon Cotton: Nitrogen Triiodide

Note 1: Yes, that is Latex embedded into the blog post.
Note 2: Originally from the Chemistry Reddit: Nitrogen Triiodide Photo

Mitch

By January 19, 2009 2 comments

So it’s me, the writer of solidasarock, and well I’ve joined the chemistry forums blog team. Studying for qualifiers have been awful, so writing has been almost nonexistent, but with finishing off TAing and watching the first years teach lab and hearing their complains that were oh so similar to mine last year, I thought I’d tackle something that’s really prevalent in some chemistry departments, particularly, my department. And that would of course me chemical edutainment.

<insert 2 cents>

I had the privilege of teaching freshmen, juniors, seniors and graduate students in my TA load, and seeing how things were run here versus my undergrad alma mater is disappointing. Back in my alma mater, experiments were ‘boring’. We didnt go into the latest nanotechnology, but we did go over very valuable experimental techniques. Twenty-thirty titrations in the first semester lab alone was enough to drive one insane, and the qualitative analysis freshman lab of having to figure out what ions were in a mixture was difficult for us fishies. Then of course, there was our ‘reward’ lab where we synthesized YBCO and then did a iodometric titration to determine the oxygen content, and then lots of other random labs that, while ‘boring’ to the students, showed important concepts that helped us conceptualize concepts.

Let’s compare that to my new department. Freshmen here do not do multiple titrations till they die. They dont even determine the concentration of their titrant in a standardization. Here, they do one titration, and do it using a pH meter. We didnt use a pH meter in undergrad until junior year for our titrations since we had to get a feel for the end point before hand. From there, they move onto ‘ubersexy’ labs, such as the synthesis of CdSe nanoparticles, Au nanoparticles. Did they at least characterize these NPs? They did one UV-vis, didnt really get told what was the significance and then were told to move on. Then later they had experiments that had very little chemistry in it at all.

I remember asking why these labs were taught, and I was repeatedly told about the ‘educational value’ of them. They were short writeups with barely any real analysis for the students. I chagrined and did my duty as a TA and taught them the best I could, inserting concepts, that while tangentially related, would actually be covered on their exams. Needless to say, my students complained at the extra work I had ‘assigned’. So writing down a few questions and having them answer it as part of their lab report was making me into a tyrannical despot. My evaluations were crappy, and I had learned my lesson.

I then spoke with one of the lab coordinators who told me about the consumerism of undergrad. We, as the TAs, are the product, and of course, the customer is always right. Of course! They pay \$ money to attend this fine institution, but if they arent getting actual quality and instead get frou frou labs that teach them little but keep them entertained where is the value?

Now this sounds like a rant. Where is your proof? Like I said, I also got to teach juniors and seniors later on in the year, and I, to my dismay would find my proof there. Here are a bunch of chemistry juniors and seniors. I was explaining the quantitative analysis lab, and asked if they had done serial dilutions before. Nope. No one had done it. Unless they were a lackey in a biochem lab and had to do serial dilutions all day for their grad/postdoc mentors. Come on, at the junior/senior level, serial dilutions should be a snap. I explained the concept, showed them how to do it, and in the end, I was still asked by juniors and seniors to whether they could get micropippeters to dilute 1000x in a 100 ml volumetric flask.

I was dumbfounded. I was aghast. I wanted to rant and rave, but I kept it in. I taught them what they needed to know and went over the concept again. I had asked if they had covered it in organic lab (since I didnt get to teach that), and they said no. I knew the freshman curriculum, and I know it wasnt covered there. There were these chemistry majors, almost ready to graduate, not knowing very basic experimental skills.

So I was on fire and wanted to teach hardcore again. I went into other concepts that tangentially related, were still useful, and that they could use the information. A lot of them were happy at the knowledge, some werent. Then fast forward to another lab. These were the same juniors and seniors. I had assigned all the questions in the lab, but some were deemed too difficult. They saw no point in those questions. Needless to say, they went to my lab coordinator and complained to their hearts content.

I had a serious talking to again. Once again, they were right, as the questions were too hard. Of course, I didnt say at this point that the lab coordinator had written the lab completely and we both deemed prior that the questions were of the right difficulty and should be good for juniors and seniors. Since I was no longer entertaining them, since I actually went from ‘nice guy TA’ to ‘no, you need to answer these questions’ I was evil. I was a bad TA.

I was distraught. I really felt like I didnt want to be a professor anymore if things were going to be like this. Then I got to teach grad students, who all went to undergrad elsewhere. Thank GOD for grad students. And now I want to be a professor again. Why? To change this system of edutainment in chemistry.

Chemistry should be fun, but to a certain extent. If you want kids to actually learn, you need to teach them important concepts, not just show them the latest and greatest sexy experiments that have little experimental value. Basic skills, especially critical thinking need to be taught. Students should be challenged in labs, cause if they’re easy, what’s the point?

</insert 2 cents>

That’s my two cents. What’s yours?

By January 12, 2009 21 comments

If I wanted to add colors to SEM pictures how would I do it? Let’s also add the stipulation that I don’t have access to PhotoShop or anything that would cost money. Illegal downloading isn’t an option. This has been on my mind for quite some time, but yesterday I sat down after dinner and developed my solution. This is my logic through the process.

1. I need a way to analyze the RGB of every pixel in an image.
2. I need to develop a simple algorithm to manipulate the RGB for every pixel.
3. Apply the algorithm and generate the colored picture.

RGB is the value for Red, Green, and Blue coded for each pixel. They run from 0 to 255. So, I wrote a script that will analyze this pixel information using php. My canvas was Yow et al.‘s recent image of colloidosomes, shown below.

A gray scale picture will have the same value for RGB. The simplest manipulations will be to hold either R, G, or B to zero and let the others retain their original value. This yields teal for R=0, violet for G=0, and yellow for B=0.

To generate blue (R=0, G=0), green (R=0, B=0), and red (G=0, B=0) you’ll need to set two values to zero.

Primary colors are nice, but if you want to have softer gentler colors you’ll need to apply an algorithm to your RGBs. For a light blue, I use the following R=(0.2 * B), G=(0.6 * B), B=B.

An orange I like is R=R, G= (0.5 * R), B=0.

If someone knows a simpler way of SEM color manipulation please share. Also, if someone would like me to make a script where you can upload your SEM image and apply a single color filter let me know.

Mitch

By December 11, 2008 19 comments fun