applied quantum mechanics

Angela has officially become an experimentalist, acquiring quantum quantum quantum data.

23:32 I don't think that this kind of Internet pedantry is related to science communication per-se, as I also get these responses on literally every video I make. Of course, a conversation in real life is different than a YouTube video in the fact that the conversation in real life is real time, and you are trying to get to the point, so constant caveats would be annoying. But that aside, I see this coming from two major sources. The most charitable explanation is that people with a shared understanding of a topic can take shortcuts in how they explain things. This is no different than using jargon to speed up commonly understood concepts. In this sense, "black body" is jargon for "so close to a black body that for our purposes it is a black body." People with a different shared understanding will not interpret words or jargon in the same way. The least charitable, and probably most likely explanation, is that there are people who, likely from some deep-seated insecurities, need to constantly posture that they know more than you, and your success as a scientist/YouTuber/functioning member of society is intimidating to them. As a result, if there is any chance at all that they can put in a little nugget of their wisdom to "prove" to the reader that they know more than you, they will jump at that opportunity, in order to bring you down a peg. The Dutch have a word for this kind of behaviour, "mierenneuken", which literally means "ant fornicating", and I love that word.

I don't understand how someone can watch your videos and can get the vibe that this is the place where we enjoy being impractical nitpickers. "It's fine" is like your literal slogan lol

In Grad School I always thought it was insane how I could take the spectra of a star light years away, do a bunch of processing and calibration, remove the effect of the Earth's motion around the sun and rotation and get a value for its radial velocity accurate to within about a meter per second.

Small brain: You're scared of magnets? You SHOULD be scared of lasers! Galaxy brain: I can fear an infinite number of things.

Your green laser is really an infrared laser going through a doubling crystal. It also has a poor or no IR filter. (for engagement)

Physics brain is where you find an irresistible urge to explain the Doppler effect, but drop in the delta function without further comment.

Absolutely love the random-rant regarding “well actually” scientific definitions. Part of every (decent) engineering/science college track is to explain to students how real engineering is completely fuzzy because the real world is fuzzy. In EE you watch students run through Kirchoff’s and then go look on the shelf for the 38.98 ohm resistor and worry about the results when they don’t find one. Same thing in physics where you spend years just slowly removing your assumptions about being in a vacuum or a frictionless plane. I think YouTube science videos are wonderful but really tend to put the general public into this state of “I understand the definition, so I’m a scientist now” and it’s just…no, you’re not.

Most scientists aren't afraid enough of their equipment, so I appreciate the safety glasses

The crappy laser probably has 3 peaks because it's probably an Nd:YAG and they have insufficient filters on the output resulting in it emitting 3 wavelengths. 808 nm is the pump wavelength, 1064 nm is the main emission line of Nd:YAG, but the visible light spectrometer probably cannot detect it and 532 nm is the converted second harmonic of the main emission line. That's why these crappy lasers are so dangerous, you think they are green but they are actually mostly near-infra-red. If the manufacturer is worth anything, they will filter out these NIR wavelengths but most crappy laser pointer manufcaturers would rather save the money and just ship it as is because you cant see these wavelengths with your eye. But if you point them into your eye and you're wearing glasses made to protect you from green light, you can end up with eye damage.

In a world where science is either dumbed down to clickbaity drivel or obscured behind incomprehensible formulae, you take the audience by the hand and show us a glimpse of what actual, applied science is about. And all of this in an engaging, entertaining way. Thank you for that!

NileRed: I should get a spectrometer

I love your content so much. As someone who's done NMR for 15 years though, my mind physically ached every time you said "spectra" instead of spectrum for a single spectrum. Keep up the amazing work.

i lovd how the best way to make sure that a lot of things are the way they are is just looking at it, but like, advanced looking

Fun fact, you can see pressure broadening in street lights (just need a diffraction grating or similar) The older street lights are a harsh yellow-orange colour because they're low-pressure and emit almost only at the main sodium line at 589nm. The newer ones are pinkish, because they use a higher pressure which a) makes the fainter lines much brighter, and b) broadens out the main orange line a lot. There's even self-absorption where the sodium outside the arc absorbs the orange light again and you end up with a dark band down the middle of it.

Great video! Whoever at Thor Labs made the decision to lend you the Spectrometer was very wise indeed! Great publicity from a great video, watched by the very folks who might be interested in their equipement!

Where scientists enjoy a discussion to gain knowledge, YouTube viewers enjoy a "gotcha" moment more than the accumulation of knowledge. Hence, the "well, actually" retorts.

I used to work for one of the major laser companies (more than one actually). One of our lasers was a tunable ring (convertible to linear) dye (or Ti:Sapph) laser, with ultra-narrow (around 100 kHz) linewidth. Because it was broadly tunable, it could be used for laser spectroscopy, when combined with a wavelength meter we made for it (it was analog, and had resolution to 6 significant digits of a wavenumber). So, you would direct the laser at a sample, and place the photodetector, where it could detect the fluorescence. The output (to a pre-Mac Apple computer) would plot the intensity from the detector, over the wavenumber. In order to calibrate the wavemeter, we had to borrow an old French almanac of iodine fluorescence, and an iodine cell. We would run a scan, in a few ranges, look for the generated peaks in the 100's of pages of the almanac, and identify them in the computer plot. When we discontinued that laser and wavemeter, (to my knowledge) there isn't a commercially available wave meter that can match that resolution. It was a very clever and simple concept. The laser light was split and sent to two paths, in a heated vacuum cell. One path was straight through to a photocell (reference), the other path went through a long crystal that rotated the linear polarization depending on the wavelength. In front of the two photocells, a variable polarizing wheel was spinning. The photocell signals were compared, and sent along with the position of the polarizer wheel, to the computer.

you have a weird talent for releasing videos on exactly what I'm covering in physics class at the moment

To those who didn't know what "black body" meant: Wikipedia: "A black body or blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. The radiation emitted by a black body in thermal equilibrium with its environment is called black-body radiation. The name "black body" is given because it absorbs all colors of light. In contrast, a white body is one with a "rough surface that reflects all incident rays completely and uniformly in all directions.""