The Weird Science of Tossing Stones Into a Lake

Interoperable writes "Researchers in Spain and the Netherlands add another piece to a centuries-old puzzle in physics: the dynamics of an object falling into water. This common occurrence has a complex anatomy that includes a thin 'crown splash' around the perimeter of the impact, a deep cavity of air following the impactor, and a high, narrow jet of water that results from the collapse of the cavity. The new research, recently published in Physical Review Letters, demonstrates that airflow through the neck of the collapsing cavity reaches supersonic speeds despite low relative pressures between the air in the cavity and ambient pressure. Such an effect has no analogue in aerospace engineering or other sciences because of the highly dynamic nature of the collapsing nozzle structure." It's funny that the APS wants to charge non-subscribers $25 to download what is available for free on the arXiv.

Comments

Looks like we elected the wrong guy

[Trepidity]

Imagine what the U.S.'s technology leadership could've been like if we had put a President in the White House who truly understood this kind of cutting-edge science.

How ARXIV and PRL work together

[imsabbel]

Just some pieces of info for people who might not know:

Nowadays, all the major publishers dont have an issue if you post a prepring on arxiv, prl included.
If you want to get a preprint out, the procedure is as follows:

1) You put something on arxiv and submit it to PRL.
2) After a few weeks/months, you get your referee reports.
3) Then you revise it, and update your arxiv version.
4) Paper gets accepted. Paper is entering the editorial process, and you get proofs.
  -> at this point, APS has contributed to the paper. The specific version proofed by PRL can no longer be uploaded to ARXIV /etc.
5) Final corrections, ready to print.

Nowadays, the proof and setting part is relatively minor. Most likely you will have written it in RevTex, and have PDF figures, so its an no issue.
But they still allow you to send them the text in word and the figures in phyical form (ink drawing, whatever), if you are really interested in it not getting published quickly.

So for most issues, a paper on Arxiv might be 99.9% identical to the final published paper, and only diiffer by the editorial issues. But you cannot know it. It might also represent a state from before the peer review.

Testing Process

[KneelBeforeZod]

I'd love to see the testing process for this.

Tries 1 - 100

1. Plop
2. Plunk
3. Plunk
4. Bloop
5. Plunk ....

Give me a grant!

Viscosity Changes the Sound Too

[Tisha_AH]

My younger brother discovered a key principle of the viscosity of fluids when he was 12 years old. He and his friend decided to drop a gigantic boulder down the center hole of an outhouse, they were standing over the "opening" to see the effect.

I imagine the sound was much "deeper" but their screams were really high.

It was a 2 mile walk to the nearest running water for them, our camping trips were never the same after that.