Physical Review Volume 53, page 318.
Not paywalled as of 2024! A miracle! It is barely one page long.
This is the paper that contains the first successful report of experimental nuclear magnetic moment observation.
They promise more at the end:and this promise was fulfilled on the later The Molecular Beam Resonance Method for Measuring Nuclear Magnetic Moments.
We have tried this experiment with LiC1 and observed the resonance peaks of Li and Cl. The effects are very striking and the resonances sharp (Fig. 1). A full account of this experiment, together with the values of the nuclear moments, will be published when the homogeneous field is recalibrated.
Molecular beams are cool because they create a one dimensional flow of molecules, which makes it easier to observe certain single-molecule effects, as it removes the multi-particle issues from experiments.
Key molecular beam experiments include:
- Stern-Gerlach experiment, which confirmed the existence of spin
- Rabi's NMR experiment, which confirmed the existence of nuclear spin
The center piece of the control system of atomic clocks is a molecular beam.
Here we list public domain academic papers. They must be public domain in the country of origin, not just the US, which had generally less stringent timings with the 95 year after publication rule rather than life + 70, which often ends up being publication + 110/120. Once these are reached, they may be upload to Wikimedia Commons!
- 2018
- Max Planck's works in Germany (1947 + 70)
- 2026
- Albert Einstein's works in Germany (1955 + 70)
- 2031:
- Max von Laue's works in Germany (1960 + 70)
- 1912: Interferenz-Erscheinungen bei Röntgenstrahlen (Interference phenomena in X-rays). Scan: archive.org/details/sitzungsberichte1912knig/page/n393/mode/2up. Clean upload: archive.org/details/interferenz-erscheinungen-bei-rontgenstrahlen
- Max von Laue's works in Germany (1960 + 70)
- 2032:
- 2042
- 1927: www.nature.com/articles/119558a0 The Scattering of Electrons by a Single Crystal of Nickel. (1971 + 70), Germer's death. Scan: archive.org/details/sim_nature-uk_1927-04-16_119_2998/page/554/mode/2up. Clean upload: archive.org/details/the-scattering-of-electrons-by-a-single-crystal-of-nickel. The Davisson-Germer experiment!
- 2049
- 1922 Stern-Gerlach experiment papers such as The experimental proof of directional quantization in the magnetic field. Stern died in 1969, Gerlach died in 1979, so 1979 + 70
- 2056
- 1961 Experimental Evidence for Quantized Flux in Superconducting Cylinders. Published in the US, so 1961 + 95.
Quantum entanglement is often called spooky/surprising/unintuitive, but they key question is to understand why.
To understand that, you have to understand why it is fundamentally impossible for the entangled particle pair be in a predefined state according to experiments done e.g. where one is deterministically yes and the other deterministically down.
In other words, why local hidden-variable theory is not valid.
How to generate entangled particles:
- particle decay, notably pair production
- for photons, notably: spontaneous parametric down-conversion, e.g.: www.youtube.com/watch?v=tn1sEaw1K2k "Shanni Prutchi Construction of an Entangled Photon Source" by HACKADAY (2015). Estimatd price: 5000 USD.
- Stern-Gerlach experiment
- fine structure split in energy levels
- anomalous Zeeman effect
- of a more statistical nature, but therefore also macroscopic and more dramatically observable:
- ferromagnetism
- Bose-Einstein statistics vs Fermi-Dirac statistics. A notable example is the difference in superfluid transition temperature between superfluid helium-3 and superfluid helium-4.
TODO understand.
Discrete quantum system model that can model both spin in the Stern-Gerlach experiment or photon polarization in polarizer.
Also known in quantum computing as a qubit :-)
It is unbelievable that you can't find easily on YouTube recreations of many of the key physics/chemistry experiments and of common laboratory techniques.
Experiments, the techniques required to to them, and the history of how they were first achieved, are the heart of the natural sciences. Without them, there is no motivation, no beauty, no nothing.
School gives too much emphasis on the formulas. This is bad. Much more important is to understand how the experiments are done in greater detail.
The videos must be completely reproducible, indicating the exact model of every experimental element used, and how the experiment is setup.
A bit like what Ciro Santilli does in his Stack Overflow contributions but with computers, by indicating precise versions of his operating system, software stack, and hardware whenever they may matter.
It is understandable that some experiments are just to complex and expensive to re-create. As an extreme example, say, a precise description of the Large Hadron Collider anyone? But experiments up to the mid-20th century before "big science"? We should have all of those nailed down.
We should strive to achieve the cheapest most reproducible setup possible with currently available materials: recreating the original historic setup is cute, but not a priority.
Furthermore, it is also desirable to reproduce the original setups whenever possible in addition to having the most convenient modern setup.
Lists of good experiments to cover be found at: the most important physics experiments.
This project is to a large extent a political endeavour.
Someone with enough access to labs has to step up and make a name for themselves through the huge effort of creating a baseline of amazing content without yet being famous.
Until it reaches a point that this person is actively sought to create new material for others, and things snowball out of control. Maybe, if the Gods allow it, that person could be Ciro.
Tutorials with a gazillion photos and short videos are also equally good or even better than videos, see for example Ciro's How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in its for an example that goes toward that level of perfection.
The Applied Science does well in that direction.
This project is one step that could be taken towards improving the replication crisis of science. It's a bit what Hackster.io wants to do really. But that website is useless, just use OurBigBook.com and create videos instead :-)
We're maintaining a list of experiments for which we could not find decent videos at: Section "Physics experiment without a decent modern video".
Ciro Santilli visited the teaching labs of a large European university in the early 2020's. They had a few large rooms filled with mostly ready to run versions of several key experiments, many/most from "modern physics", e.g. Stern-Gerlach experiment, Quantum Hall effect, etc.. These included booklets with detailed descriptions of how to operate the apparatus, what you'd expect to see, and the theory behind them. With a fat copyright notice at the bottom. If only such universities aimed to actually serve the public for free rather than hoarding resources to get more tuition fees, university level education would already have been solved a long time ago!
One thing we can more or less easily do is to search for existing freely licensed videos and add them to the corresponding Wikipedia page where missing. This requires knowing how to search for freely licensed videos:
- Wikimedia Commons video search, e.g.: commons.wikimedia.org/w/index.php?search=spectophotometry&title=Special:MediaSearch&go=Go&type=video
- YouTube creative commons video search
Related:
- relevant University YouTube channels:
- K-12 demo projects:
- books:
- Practical approach series by Oxford University Press: global.oup.com/academic/content/series/p/practical-approach-series-pas
More interestingly, how is that implied by the Stern-Gerlach experiment?
physics.stackexchange.com/questions/266359/when-we-say-electron-spin-is-1-2-what-exactly-does-it-mean-1-2-of-what/266371#266371 suggests that half could either mean:
- at limit of large
l
for the Schrödinger equation solution for the hydrogen atom the difference between each angular momentum is twice that of the eletron's spin. Not very satisfactory. - it comes directly out of the Dirac equation. This is satisfactory. :-)