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April 20[edit]

Electric vehicles[edit]

If cars, buses, motorcycles become electric then will it affect the fossil fuel industry? -- 42.110.196.234

It depends on what gets burned to produce the electric power those vehicles will charge their batteries with. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:25, 20 April 2020 (UTC)[reply]

I was wondering about that. Given that large power stations are far more efficient at extracting energy than a small car or bus engine, could it be that, even if the power stations providing the electricity for those vehicles used the same petrol as the vehicles, we would need a lot less? But there is some loss when the electricity is transported into the battery, so it could cancel out, or be worse. Has anyone seen some calculation? --Lgriot (talk) 11:13, 20 April 2020 (UTC)[reply]

Yes, it will affect the fossil fuel industry. That's the whole point (in addition to reduced local emission of pollutants). Motorcycles and cars mostly run on oil-derived fuel (in particular petrol). Buses are more variable; around here they use compressed biogas, compressed natural gas, hydrogen fuel cells (they don't say how the hydrogen was made), electricity via batteries or overhead wires (they don't say where they buy the electricity) and sometimes still diesel. In any case, most road vehicles use oil-derived fuel, but fossil fuel power stations mostly use natural gas or (rapidly disappearing in Europe) coal, so at the very least there will be a shift away from oil. And a large fraction of our electricity, expected to increase, doesn't come from fossil fuels: hydropower, nuclear, solar, wind, ...

Given the efficiency of batteries and (to lesser extend) transport losses, battery-electric cars combined with oil burning power stations could very well give higher oil consumption than petrol powered cars (but don't forget the losses from converting crude oil to petrol). But that's irrelevant as there are (practically) no oil-fired power stations. The trick is to charge battery-electric vehicles when there's such a supply of wind or solar power that the price of electricity drops to zero (or less), which guarantees that they indeed charge from clean electricity. Of course, owners of solar panels or wind farms won't make a lot of money that way... PiusImpavidus (talk) 12:01, 20 April 2020 (UTC)[reply]

I think LNG is a good bet for fossil fuel future, it's cheaper than driving on both petrol and diesel and suitable for existing engines. A taxi company in my city started out with Priuses but when it decided to go bargain busting it swapped them all for petrol cars converted to LNG. Plenty of city buses use it too, although I think the majority are still diesel (and none are electric). 89.172.105.177 (talk) 00:39, 21 April 2020 (UTC)[reply]

Note that oil at least has many important uses beyond use as fuel (e.g. as a raw ingredient of plastics). So even a total switch to non-fossil fuel power sources wouldn't eliminate the oil extraction and refining industries. Iapetus (talk) 09:42, 21 April 2020 (UTC)[reply]

Renewable electricity overtakes fossil fuels in UK for first time (October 2019). Alansplodge (talk) 12:38, 21 April 2020 (UTC)[reply]

Let's hope there won't be a second time. --Lambiam 19:57, 21 April 2020 (UTC)[reply]

Looks like the UK already imported almost half of it's energy by 2013 which The Guardian doesn't count (to Britain's carbon print). Wonder how much it's now.--TMCk (talk) 21:11, 21 April 2020 (UTC)[reply]

Penetration by particles[edit]

How exactly do beta and gamma particles penetrate human body? Do they slip through some microstructures or actually perforate, leaving microscopic holes like bullets on a larger scale? Thanks. 212.180.235.46 (talk) 11:11, 20 April 2020 (UTC)[reply]

They pass right through our atoms. PiusImpavidus (talk) 12:02, 20 April 2020 (UTC)[reply]

As shown by Ernest Rutherford in the famous experiment with metal foil. Under his direction Hans Geiger and Ernest Marsden fired alpha particles at various metal foils. The previous model of material was that mass was evenly distributed through space, so when they observed high-angle backscatter for a minority of the particles, this demonstrated that matter was instead concentrated in atomic nucleii. When Geiger reported back about the backscattered alpha particles, Rutherford said "It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you. " Mikenorton (talk) 13:38, 20 April 2020 (UTC)[reply]

So, to elaborate on this, the mental image of microstructures that particles can slip through is wrong. Think of marbles (representing the nuclei of the atoms of molecules) floating in space, practicing social distancing, where the recommended inter-marble distance is something like a half kilometre. Now you shoot at random into that largely empty space. Chances are that your bullet goes a long way before it hits a marble. Maybe it emerges at the other end without having hit anything. The molecular social distancing is the result of the van der Waals force, operating on the molecules substances are made up from. The same force keeps your feet from sinking into the floor as you stand: the molecules of your feet and those of the floor repel each other when approaching each other at a very short distance. --Lambiam 15:59, 20 April 2020 (UTC)[reply]

The beta rays will disturb the electrons as they pass, perhaps ionising the atoms, or causing molecules to become excited, or to vibrate more. As suggested above, to actually make a hole you would actually have to hit or move a nucleus of an atom. For gamma rays, the photons do not punch a cylindrical hole, and only have an effect once they hit something and are absorbed and or scattered. You can expect disruption where they hit. Graeme Bartlett (talk) 00:34, 21 April 2020 (UTC)[reply]

Alpha particles colliding with nuclei can cause atoms to get displaced. It has been suggested that one can also search for dark matter this way by searching for tracks of atoms displaced by collisions with dark matter in certain minerals at some depth, see here. Count Iblis (talk) 03:31, 21 April 2020 (UTC)[reply]

Predatory Journals[edit]

Hi, while writing a draft on a Medical policy and saving it. I got a message saying some of citations might be “Predatory Journals”. I would like to know more about this particularly, wether any of my sources cited are in Blacklisted category. Where do I find more information on this? Regards Santoshdts (talk) 15:32, 20 April 2020 (UTC)[reply]

See WP:VANPRED. Mikenorton (talk) 15:43, 20 April 2020 (UTC)[reply]

What animal is this?[edit]

Is that a hippo? Or a warthog? It's from Central Africa (Gabon or neighboring territories), this is certain. Thank you! --Edelseider (talk) 16:21, 20 April 2020 (UTC)[reply]

Yes, it is a hippopotamus skull, as you can confirm here by comparing the two. In your picture, the top and bottom are not correctly aligned; the upper jaw is rotated clockwise (as viewed from looking over the top of it) relative to the lower jaw. --Jayron 32 17:53, 20 April 2020 (UTC)[reply]

@Jayron32: Ah, okay, thank you very much! --Edelseider (talk) 20:18, 20 April 2020 (UTC)[reply]

What is this metal object?[edit]

I was walking in a forested area in south-east England and I found this metal disc thing embedded in the ground.

What is it?

Something used in forestry or agriculture? Thank you. --Polegåarden (talk) 21:24, 20 April 2020 (UTC)[reply]

Unknown object
Unknown object

I have no idea, but ~~the second photo clearly doesn't seem to be the same object~~. What's up with that? --76.71.6.31 (talk) 23:45, 20 April 2020 (UTC)[reply]

I think they are the same. The first object isn't lying on the ground. It's sitting on top of the axle/post/metal rod(?) it's attached to. The second pic is a side-on view. But I have no idea what it is. HiLo48 (talk) 00:25, 21 April 2020 (UTC)[reply]

I agree that the in the first photo the disk may not be lying on the ground, although we were told that the thing is "embedded in the ground". But it is clearly circular and has a circular recess in the top, and a screw or bolt protruding at least 1/2 inch or 1 cm. ~~The object in the second photo has four straight sides, no circular recess, and no protruding screw.~~ So...? --76.71.6.31 (talk) 03:15, 21 April 2020 (UTC)[reply]

The second image is from directly side-on. We can't see anything about the top or the bottom surfaces, such as if there is a depression, or if there is a bolt in the depression that is not taller than the depression. Several of the other items visible on the ground in the two images match each other. Because I'm going stir-crazy from travel restrictions and needed a break from work-at-home, I annotated four such details (go to File:Unknown_object_in_rural_area.jpg and File:Unknown object in rural area 2.jpg in two adjacent windows, hover your mouse over each to see identified regions). DMacks (talk) 04:10, 21 April 2020 (UTC)[reply]

Oh, of course. Sorry about the distraction. --76.71.6.31 (talk) 18:05, 21 April 2020 (UTC)[reply]

I think it is a feeding station for gamebirds. Greglocock (talk) 00:29, 21 April 2020 (UTC)[reply]

That would have been my guess based on shape (or a mounting on which a feeder is bolted), but it seems too low (squirrels and other ground creatures could get up to it). DMacks (talk) 04:10, 21 April 2020 (UTC)[reply]

Thank you for your replies. Yes, the two photos are of the same thing. I've heard that it might be part of an old pheasent feeding station with some part missing. --Polegåarden (talk) 06:26, 21 April 2020 (UTC)[reply]

Something like this perhaps?. Alansplodge (talk) 12:34, 21 April 2020 (UTC)[reply]

Flu Vaccine Effectiveness[edit]

I've heard that all the flu vaccine does is decrease the time you have it, that does not stop you from getting it. Is this true? Pealarther (talk) 22:56, 20 April 2020 (UTC)[reply]

See Influenza vaccine. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:44, 20 April 2020 (UTC)[reply]