A couple of quick thoughts:
It might be helpful to spell out what āTOFā is, since itās not otherwise delineated in the card (same for MS-MS). Also we want to be sure that weāre using the same terminology; the card text uses m/z for mass/charge whereas the suggested addendum uses M/Q.
Separately, I think we can distill this down a bit and capture the (arguably important) essence while trimming the verbosity a touch. Itās important info, so I donāt want to leave it out, but itās also important to be (at least somewhat) parsimonious when including significant additional text length to a field.
Let me know what you think. 
Just edited with suggested changes. I tried to trim it down the best I could while still including the relevant info for what methodology separates the two types of mass spectrometry as well as their relationship to the M/Z ratio. Wasnāt able to trim that much if we want to include these details. Do you have any suggestions?
Could just add a proportional symbol and avoid the whole āwhich is directly proportional to the M/Z ratioā. Example: Time-of-Flight Mass Spectrometry (TOF-MS) separates ions by travel time to detector. Time taken ā M/Z ratio.
Yeah, I think thatās a lot better. Acronyms we for sure want to make sure we specify, since we donāt want to be in the business of presuming that anyone knows them off-hand
Also still m/z (as opposed to M/Z); whichever we use we want to be consistent across the deck as much as possible.
Anytime we can, we want to be diligent in adding text. Huge amounts of text are not user-friendly, and while they contain lots of information they also hog precious (screen) real estate so we want to be as judicious as we can, balancing merit of information against the real estate necessary to convey it. This, usually, means trying to be concise as much as possible (itās not always possible).
Iāll let @kevinpanini take a look at it as well; Iāll circle back to it later this evening but the only other thing that stands out to me is maybe putting in a hyperlink to the KA video as well.
That makes sense. Thanks for the suggestion/guidance. I updated the M/Z to m/z for consistency with the front of the card. Also inserted the KA link for convenience if you decide to include it. Upon a quick review I donāt see any cards with two videos in the extra section. Is this intentional/how is this handled? the Bozeman video offers a more comprehensive overview of mass spec while the KA link includes a specific derivation for the m/z relationship to the radius of curvature.
Itās for sure less common; in this case I think, all things being equal, if nothing else Iād prefer to have MCAT-specific sources when possible.
This Youtube video is 11 years old, which is fine (itās not like the underlying chemistry or physics have changed and, to be fair, the KA video itself is also about 10 years old), but in a pinch I think itās nicer to have sources that align with the exam to the extent that weāre able.
Also, KA has the added advantages of being the only MCAT-specific resource that is entirely free and freely available, which has added benefits of democratization for its inclusion (compared to, say, Kaplan or UWorld).
In this case, though, I donāt see that thereās any harm to keeping both. Itās not unusual that there will be multiple sources for any given topic, and maybe thereās benefit to giving folks options. Also, as you point out, in this case the Youtube video is quite solid (not all are so good). Thereās no hard rule on this, though, as per Ankihub guidelines. I donāt think anyone will slap our wrists if we want to include two links.
In normal constraints, I donāt know that I would go around just adding random 10+ year-old Youtube videos to existing cards but in this case itās been in this card for a while, we know itās a reasonable source, and no oneās complained about it so I donāt imagine leaving two links in the bottom of the Extra field is going to cause anyone to lose any sleep.
I donāt know if it matters, really, but trying to think if itās better to have the KA link point to Youtube, or the KA site specifically, or if it really matters either way.
Thatās a good point on having the link go to YT vs the KA site. Iām pretty partial to actually linking directly to the KA site within the MCAT course. Kind of a nice courtesy to the user to be able to watch the video related to the card and also watch any lectures related to this topic to fill in any information if needed directly in the MCAT course without having to search for it. Updated the link for now. LMK what you think.
Yeah, I think all things equal itās probably better practice to link directly to the KA website, though I donāt know that it needs to be a hard-and-fast rule, necessarily
At the very least itās nice to give KA (doing the Lordās work) the traffic, as opposed to YT.
The suggestion is looking sharp. We might should tag it by the UWorld QID as well, and I still want to give @kevinpanini a chance to take a look at it, for practice and corroboration and any thoughts he might have, but I think itās looking handsome.
Haha agree on the traffic part. Iām a little confused by the UWorld QID tagging. On the top of UWorld the question is listed as QId: 400704 (4908855). Which number is used for the tag? Does it matter? When trying to tab over across #AK_MCAT_v2::Uworld I see both examples of a 6 digit code and a 7 digit code suggesting there is variability in which is used.
Though most are the 6 digit code by far.
Should be the 6-digit code. I ended up doing about 95% of the UWorld tags, though some of them were done before me and I canāt guarantee the uniformity of those earlier efforts. Iām also not sure how the QID-to-flashcard addon is coded and maybe it is able to parse either length code. I really donāt know about that level of detail, tbh.
Tagging by UWorld QID was, like, maybe 5% done when I started and should be 90-95% done now. Iām positive there are new questions, or some that I missed, though it shouldnāt be a ton.
The tagging format ends up like this and should be able to be suggested as any normal tag:
#AK_MCAT_v2::#UWorld::555555
Where, instead of ā555555ā you add the typical 6-digit QID, of course.
Thank you for adding them! I just added the tag with the UWorld code.
@Brian_BH @pkaps01 I have done the world QID and looked at the explanation for both the Kaplan and Uworld textbooks. I think neither form of mass spectroscopy is important enough to even be included in the extra section. Neither textbooks look at the various types of Mass spec and that is for good reason, knowing the types is beyond the scope of the MCAT. While it may help you answer this specific question, I have looked at the question, and everything that is required for you to solve the question is included in the passage.
@kevinpanini Itās true that in this specific UWorld question that there is enough info about these methods to answer the questions. However, in the KA video it is a direct explanation/derivation for the relationship between curvature and m/z ratio in magnetic sector mass spectrometry and in the UWorld question they take time to specifically show the derivation between radius and m/z ratio. Given this, Iām not sure how it would be possible to say definitely that this relationship couldnāt be tested in a discrete question. Moreover, UWorld lists TOF-MS and MS-MS in their Educational Objectives for the question which is used to describe info that is expected to be understood/known rather than just being a summary of info provided in the passage.
while your right that this is in the educational objective i believe if the content were truly testable material it would both be mentioned in the textbook. the only one i see in either kaplan or uworld textbook is the MS-MS one and that is shown as an example of mass spec. They dont even mention it as MS-MS and only show it as one example to show the components. Im not 100% sure that this information is relevant enough to be included and even the question that it is tested on in 400700 may be better solved using basic knowledge from the card as well as passage informtion.
UWORLD, AAMC/Khan academy suggest that you should know the MS-MS concept that radius of curvature is directly proportional to m/z ratio which is what allows you to separate ions. Though less direct than UWorld and the KA video, Kaplan describes MS-MS as well:
Kaplan: Mass spectrometry involves the ionization and fragmentation of compounds; these fragments are then run through a magnetic field, which separates them by mass-to-charge ratio.
This should support MS-MSā inclusion and the related curvature to m/z relationship in my opinion. Itās pretty reasonable to assume this is fair game for a discrete if all of these sources discuss it. Moreover, KA was created in collaboration with the AAMC from my understanding and if they spend an entire 12 minute video deriving this relationship it suggests itās worth knowing to me. Personally, any KA video entirely devoted to a single topic that is not mentioned elsewhere in the deck I would create a separate card for in my own collection. I think this at leasts warrants inclusion in the extra section.
I would agree that TOF-MS is more difficult to make a call on. Itās not explicitly mentioned by Kaplan or KA. It is included in the UWorld section bank Educational Objectives but from my understanding not directly in the UWorld textbook (I donāt have access to it but thatās my understanding from your comment). This makes it more of a judgement call. Not sure if it does much harm in the extra section. At the very least, Iām going to reverse the order in the extra section so MS-MS comes first. LMK what you think!
Well, it appears to me, then, that we run into a conundrum:
It seems that, without explicit corroboration, we canāt rule out the level of detail as being theoretically testable. But, we also stand in a position of not having any active indication that it is discreetly testable (without also having explicit passage info to support it, which is distinct).
The most obvious limiter here is thus: if we lean on inclusion of every detail that is mentioned in a passage (and that otherwise has support in that passage), the deck will undoubtedly bloat exponentially (this is undesirable).
There is always a (somewhat fine) line between maintaining a deck that is high-yield versus one that is entirely comprehensive. The mission statement, as it has been communicated to me, is that the deck is geared to be somewhere between the two, leaning somewhat in favor of high-yield. There are other examples I can give, and we can discuss it further if desired, but the short version is that all-things-being-equal itās important to lean on restraint in adding details such that we try to add what is definitely necessary, and demonstrate a lean judiciousness beyond that.
With that, given that TOF-MS isnāt mentioned in either Kaplan or UWorld textbooks it gives me a bit of pause. That leaves Khan, which is a stickier case. On one hand they do have an active partnership with the AAMC, on the other hand that partnership was initially slated to end in 2021 and was hastily continued (and, with the exception of P/S, Khanās level of detail is known to be less tightly wound to the MCAT as whole; sometimes giving too much, or too little, detail comparatively). All things being equal, my habit is to give a little bit more weight to Kaplan/UWorld with the exception of psychology/sociology where Kaplan is known to be pretty awful and Khan comparatively shines.
From what I can gather of the conversation in this thread thus far, I sort of imagine the compromise position for the Extra field being something like:
Mass spectrometry separates ions by mass-to-charge ratio (m/z), most commonly by radius of curvature
(r = (\frac{mv}{qB}))
This is probably also a card where an image would be worth a thousand words, tbh
Itās maybe a little ābusierā than I would love, but OpenStax has this image which might be a good candidate (though if anyone else has better options, or another image they prefer Iām certainly not married to this one):
Open to more thoughts, but I think weāre making progress for sure.
I think thatās a good solution. Radius of curvature being proportional to m/z ratio probably wouldnāt have been intuitive for people who didnāt have a good mental image/understanding of a mass spec set up. An image would definitely solve that issue and better convey the info. I do wonder if an image like the one linked below would be better which directly states that the lightest ion is deflected the most. Removes the extra step of users having to reason through the image how m/z ratio affects radius of curvature.
Found it on KA. But has the openstax info on the bottom left.
I do like that image better; itās a lot more clear. And bonus points for having both a mock-up of the instrumentation itself alongside a graphical representation of example results (which is likely how itāll show up visually in a lot of practice questions).
And, as you point out, I think it helps for those who might not be as familiar with spectroscopy and thus the visualization may not be as immediately intuitive. Thatās a great find.