1

Geology, Palaeontology & Archaeology / Re: What are Rocks & Sand?

« on: 31/05/2023 23:28:13 »

Any ordinary looking small rock on the side of the road, what is it made up of?

A native rock (one not put there by the road construction process) is sometimes just the local stuff, which would be loose slate near me.

what's inside a single miniscule grain of sand?

Sand is usually something from the watershed of nearby rivers. I grew up in Michigan where the entire lower part of the state is made up of sand and rocks, made of, well, Canada actually. None of it is 'native', but instead all pushed there from up north. Somewhere deep down is actual Michigan rock, but none of us has actually seen it.
Go to Florida and all the sand is made entirely of ground-up sea shells. In Hawaii the sand is black volcanic stuff. Local stuff in all cases.

Where I live now the beaches are all fake, so who knows where they found the stuff.

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Marine Science / Re: How do sea shells get their shapes/patterns?

« on: 31/01/2022 17:10:13 »

I don't think there is proof that there is NOT ANY influence of the hemisphere, but if there is any, it is VERY, VERY slight.

From a physics standpoint, the Coriolus effect comes from the relationship of angular momentum and torque in correlated spinning systems. It is really only significant for very large spinning systems (like hurricanes or other weather systems), and has essentially no influence on which direction is favored for water going down a drain (it is a non-zero influence, but almost certainly less significant than slight imperfections in the drain or basin itself, or as is the case with toilets, which direction the water is being pushed). It would be an even more tenuous connection linking something essentially static (shells with right-handed or left-handed twists don't have different angular momenta unless they are spinning differently—I don't think growth would be a factor)

From an biological (and observational) standpoint, the twists don't appear to depend on where the shell matured. It appears largely species-dependent (genetically determined).  The following article discusses some biochemical (gene editing) studies that demonstrate that, at least for some snails, we can identify which gene(s) is (are) involved in determining how the chirality gets defined.
https://www.pbs.org/newshour/science/how-a-snails-shell-gets-its-twist

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Plant Sciences, Zoology & Evolution / Re: Why do cockerels crow in the morning?

« on: 08/02/2021 18:51:15 »

Do hens actually do it. 

Mine do. Then they walk away and get on with the serious business of destroying the garden whilst the egg freezes.

I don't think you can regard the domestic chicken as a normal bird. Every other species in my garden lays a clutch of eggs once or twice a year then either takes turns with the male to brood them or sits on them and gets fed by the male until they hatch. The idea of laying and abandoning one egg every day doesn't make sense.  Now and again one of the girls "goes broody" and sits on everyone's eggs for a few days but she pretty soon gets the message  that, in the absence of a cockerel, even that level of normal avian behavior is unproductive. And they can't claim they are being drugged - until the outbreak of avian flu, mine were entirely free range but had the wit to huddle together in a henhouse at night, and always lay in the nestbox. Weird and wonderful creatures.

4

General Science / Re: Can someone please explain how what is shown in this photo happens?

« on: 07/01/2021 20:48:25 »

This can happen when the sun is at the right angle, pretty much overhead or just over the point where the hose leaves the planter. This foreshortens the shadow and emphasises the curve so it appears to be looped.

Here is a kitchen worktop version using an electric cable and a torch:

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Plant Sciences, Zoology & Evolution / Re: Can life exist beyond the deepest point in the ocean?

« on: 11/11/2020 08:52:15 »

Can life exist beyond the deepest point in the ocean?

Over the past few years, scientists have been astonished by the number of microorganisms living in deep rocks - even in deep gold mines.
- Presumably this would include rocks under the Mariana trench.
- This is a place where ocean floor plunges beneath the Mariana tectonic plate, potentially taking living microbes deep under the ocean floor.
See: https://en.wikipedia.org/wiki/Mariana_Trench

The appearance of the Mariana Trench is that of a wound that is beginning to close up, this unrelated similarity provoked the initial idea that maybe at one point it was open and the ocean expanded significantly

The Mariana trench is part of the Pacific "ring of fire", characterized by subducting ocean floor, volcanoes and earthquakes.

I understand from this week's Naked Scientists podcast that the Pacific Ocean has been showing this behavior since the breakup of Pangaea, which is put at around 300 million years ago.

If you want to see ocean floor that is spreading and opening up, look at the mid-ocean ridge in the Atlantic ocean. At it's northern end is Iceland, which is effectively splitting in half due to sea-floor spreading.
Listen: https://www.thenakedscientists.com/articles/interviews/ground-moving-beneath-our-feet
See: https://en.wikipedia.org/wiki/Pangaea
https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge

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General Science / Re: How are electricity towers designed?

« on: 09/08/2018 11:47:08 »

Start with the statutory clearance of the conductors from each other and whatever they pass over.

Specify the conductors according to the intended maximum working current

Calculate the insulator length required for the voltage and assumed weather conditions

Calculate the catenary drops between pylons for the specified design tension of the conductors

Design the simplest tree structure (single vertical insulators) required to support a straight run, allowing for windage and the weight of the wires between pylons

Calculate the straight-run pylon spacing required by the clearance, insulator lengths and catenary drops

Determine the maximum tolerable angular deflection between adjacent straight runs

Design the tree structure required to anchor each turn that exceeds that value (pairs of horizontal insulators)

Consider whether additional tensioning or tension relief trees (horizontal insulators) are required between the simple trees

Design any junction or terminal trees that may be required

Now go to an applied maths textbook and look up "just stiff structures" to support the outline trees you have drawn

At this point the geologists, accountants, countryside preservation planners and electrical load planners will tell you that the proposed route and capacity have changed.