This is the only way to truly understand and appreciate the subject.

Understanding the experiments gets intimately entangled with basically learning the history of physics, which is extremely beneficial as also highlighted by Ron Maimon, related: there is value in tutorials written by early pioneers of the field.

"How we know" is a basically more fundamental point than "what we know" in the natural sciences.

In the Surely You're Joking, Mr. Feynman chapter O Americano, Outra Vez! Richard Feynman describes his experience teaching in Brazil in the early 1950s, and how everything was memorized, without any explanation of the experiments or that the theory has some relationship to the real world!

Although things have improved considerably since in Brazil, Ciro still feels that some areas of physics are still taught without enough experiments described upfront. Notably, ironically, quantum field theory, which is where Feynman himself worked.

Feynman gave huge importance to understanding and explaining experiments, as can also be seen on Richard Feynman Quantum Electrodynamics Lecture at University of Auckland (1979).

Videos should be found/made for all of those: videos of all key physics experiments

The key thing in a good system of units is to define units in a way that depends only on physical properties of nature.

Ideally (or basically necessarily?) the starting point generally has to be discrete phenomena, e.g.

What we don't want is to have macroscopic measurement artifacts, (or even worse, the size of body parts! Inset dick joke) as you can always make a bar slightly more or less wide. And even metals evaporate over time! Though the mad people of the Avogadro project still attempted otherwise well into the 2010s!

Standards of measure that don't depend on artifacts are known as intrinsic standards.

A language that allows you to talk to and command a computer.

There is only space for two languages at most in the world: the compiled one, and the interpreted one.

For 2020 now, when you have a choice, you must go for:

Those two are languages not by any means perfect from a language design point of view, and there are likely already better alternatives, they are only chosen due to a pragmatic tradeoff between ecosystem and familiarity.

Ciro predicts that Python will become like Fortran in the future: a legacy hated by most who have moved to JavaScript long ago (which is slightly inferior, but too similar, and with too much web dominance to be replaced), but with too much dominance in certain applications like machine learning to be worth replacing, like Fortran dominates certain HPC applications. We'll see. Maybe non performance critical scripting languages are easier to replace.

C++ however is decent, and is evolving in very good directions in the 2010's, and will remain relevant in the foreseeable future.

Bash can also be used when you're lazy. But if the project goes on, you will sooner or later regret that choice.

The language syntax in itself does not matter. All that matters is how many useful libraries and tooling it has.

This is how other languages compare:

Great overview of the earlier history of unit standardization.

Gives particular emphasis to the invention of gauge blocks.

Good because unnecessary state is the source of much evil.

Even if we cannot do everything in functional, we should at least strive to clearly extract functional substes in what we do.

Uses the frequency of the hyperfine structure of caesium-133 ground state, i.e spin up vs spin down of its valence electron $6s^1$, to define the second.

International System of Units definition of the second since 1967, because this is what atomic clocks use.

TODO why does this have more energy than the hyperfine split of the hydrogen line given that it is further from the nucleus?

Why caesium hyperfine structure is used:

It is rare to find a project with such a ridiculously high importance over funding ratio.

E.g., as of 2020, their help login help.openstreetmap.org/ shows MyOpenID as an option, which was discontinued in 2014, and not Google OAuth.

They do still seem to have a bit more activity than gis.stackexchange.com/questions/tagged/openstreetmap on Stack Exchange.

Complaints:

All of this is a shame, because they do have some incredible data that you cannot find easily on other maps because people just edited it up.

Interestingly, the very first programming language with an actual implementation was interpreted: Short Code in 1950.

This is not surprising, as interpreters are easier to write than compilers.

And just like modern scripting languages, it reduced execution speed by about 50x.

A series of systems usually derived from the International System of Units that are more convenient for certain applications.