Electron holography Updated 2025-07-16
Microphone Updated 2025-07-16
Testing and Circuit for a Condenser microphone by RSD Academy (2018)
Source. Not very numerical, but shows a simple working breadboard circuit and an oscilloscope. He whistles with his mouth to get a pretty pure frequency.
That type of microphone requires a bias voltage. The circuit is in Ciro's ASCII art circuit diagram notation:
DC_9---R_10k--+--MICROPHONE--+--G
| |
+-------V------+Soundwaves on an oscilloscope by Animated Science (2015)
Source. Dude speaking to microphone. Some analysis of how different sounds look like. No circuit diagram. Loudspeaker Updated 2025-07-16
Transcendental number conjecture Updated 2025-07-16
There's a billion simple looking expressions which are not known to be transcendental numbers or not. It's cute simple to state but hard to prove at its best.
Open as of 2020:
Bibliography:
- www.quantamagazine.org/recounting-the-history-of-maths-transcendental-numbers-20230627/ How Math Achieved Transcendence by David S. Richeson (2023).
Semisynthesis Updated 2025-07-16
Cell-free protein synthesis Updated 2025-07-16
Cultured food Updated 2025-07-16
- 2024 www.uktech.news/foodtech/alternative-meat-research-centre-20240829A research centre examining the implementation of alternatives to meat, backed by £38m, will be launched by the University of Leeds.
- 2024 techcrunch.com/2024/08/04/even-after-1-6b-in-vc-money-the-lab-grown-meat-industry-is-facing-massive-issues/ "Even after $1.6B in VC money, the lab-grown meat industry is facing 'massive' issues"
- www.reuters.com/markets/commodities/hoxton-farms-raises-22-million-cultivated-animal-fat-2022-10-20/ Hoxton Farms, cultured animal fat
Histology Updated 2025-07-16
Tinker Tailor Soldier Spy adaptation Updated 2025-07-16
Boltzmann constant Updated 2025-07-16
This is not a truly "fundamental" constant of nature like say the speed of light or the Planck constant.
Rather, it is just a definition of our Kelvin temperature scale, linking average microscopic energy to our macroscopic temperature scale.
The way to think about that link is, at 1 Kelvin, each particle has average energy:per degree of freedom.
For an ideal monatomic gas, say helium, there are 3 degrees of freedom. so each helium atom has average energy:
Another conclusion is that this defines temperature as being proportional to the total energy. E.g. if we had 1 helium atom at 2 K then we would have about energy, 3 K and so on.
This energy is of course just an average: some particles have more, and others less, following the Maxwell-Boltzmann distribution.
Equipartition theorem Updated 2025-07-16
Thermodynamic potential Updated 2025-07-16
chemistry.stackexchange.com/questions/7696/how-do-i-distinguish-between-internal-energy-and-enthalpy/7700#7700 has a good insight:
To summarize, internal energy and enthalpy are used to estimate the thermodynamic potential of the system. There are other such estimates, like the Gibbs free energy G. Which one you choose is determined by the conditions and how easy it is to determine pressure and volume changes.
Equation of state Updated 2025-07-16
Entropy Updated 2025-07-16
OK, can someone please just stop the philosophy and give numerical predictions of how entropy helps you predict the future?
The Unexpected Side of Entropy by Daan Frenkel
. Source. 2021.- www.quantamagazine.org/what-is-entropy-a-measure-of-just-how-little-we-really-know-20241213/ What Is Entropy? A Measure of Just How Little We Really Know. on Quanta Magazine attempts to make the point that entropy is observer dependant. TODO details on that.
Phase transition Updated 2025-07-16
TODO can anything interesting and deep be said about "why phase transition happens?" physics.stackexchange.com/questions/29128/what-causes-a-phase-transition on Physics Stack Exchange
Refrigerator Updated 2025-07-16
Refrigerator - How Does It Work? by Curiosity Show
. Source. Temperature Updated 2025-07-16
For scales from absolute 0 like Kelvin, is proportional to the total kinetic energy of the material.
Vacuum Updated 2025-07-16
Fisher Scientific Updated 2025-07-16
Thermo Electron Updated 2025-07-16
There are unlisted articles, also show them or only show them.