explain xkcd - User contributions [en]

Talk:2935: Ocean Loop

2024-05-20T22:23:04Z

172.70.85.241:

The 'standard' and '2x' sized images had unexpected sizes, so a Trivia section has been automatically generated, and an imagesize parameter has been added (at half size) to render the image consistently with other comics on this website. --[[User:TheusafBOT|TheusafBOT]] ([[User talk:TheusafBOT|talk]]) 20:47, 20 May 2024 (UTC)

Is there anyway to get notifications when a new comic comes out? I'm always late to these 21:27, 20 May 2024 (UTC)Jush
:I believe that there may be a Twitter (or X, or Xwitter, whatever we're calling it out) announcement direct from Randall's account, but I don't use that myself. And, like me, you were here ''right as it came out'', more or less, so so don't worry too much. You ''could'' write your own BOT-like poller (various ways, but do at least considerately throttle it back to checking perbaps no more frequently than every 15 minutes, 'cos too many people doing that would be 'problematical'), if you can't find a push-notifying service that does most of the hard work for you (and a whole host of other subscribers). [[Special:Contributions/172.70.85.241|172.70.85.241]] 22:23, 20 May 2024 (UTC)

Happy Victoria day to anyone else in Canada! [[Special:Contributions/162.158.146.235|162.158.146.235]] 21:39, 20 May 2024 (UTC)

Due to not being told about any Edit Conflict, I managed to co-edit the initial explanatuon with A.N.Other (sorry, haven't checked who, probably the first major editor in the page-history). I've put the most useful bit (IMO) of their article into mine, but some of it seemed wrong. Or at least not right.
*"because of the size and speed of a cruise ship, the ship likely wouldn't make it around the loop without falling off" - well, given the mass of water nicely holding itself to the loop, a ship floating around in it at the same speed would be holding itself to the loop quite nicely (moreso, perhaps, with its CoG taking a tighter loop than the fluid-loop).
**Of course, it could be slower, but that would mean fighting the current. Whatever huge velocity the water is going, you'd have to be capable of going full-reverse at ''significant'' speed to overcome that,
***Well, you could be ''just'' less than the ''just'' more than fast-enough water, but it's probably significantly faster than loop-speed, or a lot of edge-surface water would shed out of the topmost loop-trough due to fluidic friction against the trough itself.
***And there's the acceleration needed to match the fluid flow-rate, but that causes problems before 'falling off' is an issue. Imagine suddenly finding yourself going hundreds (thousands?) of knots sternwards in still water. Probably what it'd feel like, before even getting to the tilt (by which time, any ship that had survived is probably now close to water-speed).
*"Second even if they managed to make it through without falling, many of the passangers would abtain extreme injuries and/or likely fall off the ship all together (unlike {{w|rollercoasters}} the passengers aren't strapped down)" - If you experience negative Gs in a rollercoaster, it's not a true loop (just an awkward inversion). You should normally always stay at positive Gs, albeit at somewhere within 0<Gs<1 (which ''feels'' like negative, but is just short of weightlessness). Being strapped in is still important, but mostly for forces lateral to "local down" for where you are on the ride.
**...or, of course, if the ride malfunctions and leaves you stationary and inverted. Which happens, but that's not at all intended in most situations. There'd be no way an 'otherwise normal' flume-loop would do that, though refering back to the need of your ship to experience initial acceleration before it even hits the loop (and final deceleration once it exits it).
*"Third, because of the way the loop's designed, several hundreds (if not thousands) of tons of water is being launched onto the top of the cruise ship at a high speed. Needless to say, this would not only likely capsize the ship, but would also flatten any passenger on the deck." - The sudden undersea current is going to be a problem, but it's not going to be directed over the ship (save ''completely'' over the ship, in the loop far above).
**What you'll have is the turbulent local sea conditions. There'd be a 'standing wave-trough' in front of the point the jet of water is shown to emerge, itself probably a catastrophic problem for a ship, even an ocean-going one built in expectation of occasionally meeting {{w|rogue waves}}) and all the problems involved in traversing such rough seas. If your vessel can survive that (without spinning sideways and hitting the flume-trough, or breaking its back due to the extremely uneven and changing buoyancy along its length) then it's probably going to survive the much smaller amount of water that splashes 'over' its upper superstructure, compared to whatever relative mastrom of flow there will be passing under/against its (nominally) below-waterline hull.
I don't know how much 'reality' Randall has invested in this premise (I presume little, given the lack of pressure-trough in the 'still' water just short of the jet-emergence, nor any distortion in the sea surface wherever the jet originally sucked its water in from), but a lot of the issues of the looping-the-loop "What if" train will be the prime factors, plus maintaining general control (in river navigation, going downstream, between bridge piers, you really have to power your vessel forward, faster than the river itself, or risk losing yaw discipline on your craft). All the rest is icing on the cake of improbability. [[Special:Contributions/172.70.85.241|172.70.85.241]] 22:23, 20 May 2024 (UTC)

2929: Good and Bad Ideas

2024-05-07T11:28:45Z

172.70.85.241: /* Explanation */

{{comic
| number = 2929
| date = May 6, 2024
| title = Good and Bad Ideas
| image = good_and_bad_ideas_2x.png
| imagesize = 595x522px
| noexpand = true
| titletext = While it seemed like a fun prank at the time, I realize my prank fire extinguishers full of leaded gasoline were a mistake.
}}

==Explanation==
{{incomplete|Created by a BLOOD FOR THE BLOOD GOD- Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This is a scatter plot comparing how good an idea sounds to how good the idea actually is. For example, leaded gasoline sounds like a good idea due to the anti-knocking effects, but is actually a bad idea due to lead toxicity. Fake prank fire extinguishers however sound bad and are bad as they can result in a dangerous situation in an emergency. Putting mold on infections sounds like a bad idea, but this could be referring to Penicillin, an antibiotic.

The title text combines leaded gasoline and a fake prank fire extinguisher into something that is worse than either. Not only is the fire extinguisher fake, it also releases flammable material onto the fire, and there is the additional lead toxicity.

{| class="wikitable"
|-
! Idea !! What it means !! How good it sounds !! How good it actually is !! Explanation
|-
|Leaded Gasoline||Adding {{w|Tetraethyllead|tetraethyl lead}} to gasoline to reduce noise and/or increase performance||++||---||Leaded gasoline was introduced in the early 1920s to eliminate engine knocking and greatly increase fuel efficiency and engine performance. Lead, however, is toxic. Burning the leaded gasoline in an engine releases the lead in the air. This is bad, and was known to be bad at the time, which is why there was an extensive PR campaign by oil companies to prove the alleged safety of the new product which, broadly speaking, succeeded up until the 1970s.
|-
|Bloodletting||Releasing "bad blood" from the veins||---||---||You need (most of) your blood.{{Citation needed}} Bloodletting has been performed as a medical procedure for at least 2000 years until it was considered pseudoscience from the 19th century, when the harmful effects became known. The idea was to withdraw blood to balance the body's "humors". Nowadays {{w|phlebotomy}} is only used therapeutically in a small number of cases, such as hemochromatosis (too much iron in the body).
|-
|{{w|Asbestos}}||Mineral which does not burn and is good insulation, isolation, and fire-retardant||+++||---||Asbestos was used extensively in buildings throughout most of the 20th century. Sadly the microscopic fibers which make up asbestos greatly increase the risk of cancer when inhaled.
|-
|Extension cords with prongs on both ends||allows easy connection between 2 female connectors||0 (neutral)||---||Prongs on both ends would make it easier to plug the extension cord in on either side. But once plugged into an outlet, the other end becomes a serious shock hazard.
|-
|Stair Kayaking||Riding down a flight of stairs in a {{w|kayak}}||--||---|| Stair kayaking is a stunt where a person positions a kayak at the top of a flight of stairs and then, using their paddle to push off, rides the kayak down the stairs. This poses significant easily foreseeable risks of injury or death, as well as being very bad for the kayak, which is designed to ride on water, not concrete.
|-
|Fake prank fire extinguishers||||---||---|| The idea of placing fake fire extinguishers as a prank, presumably so that a person who thinks they are grabbing a real fire extinguisher will instead find a decoy, sounds very dangerous and potentially life-threatening for many people, and it would, in fact, be highly dangerous. In the United States, (and presumably most countries), this would also be a felony in most, if not all, jurisdictions. An example of a similar situation, although not intended as a prank, can be found [https://twitter.com/ThatSamWinkler/status/1657154071051239424 here].
The title text expands this idea by having the prank fire extinguishers filled with (leaded) gasoline. This is literally adding fuel to the fire.
|-
|Always saying what you think||...regardless of the feelings of others or other considerations||++||--||Openness and honesty are seen as positive character traits in people. However, taken to the extreme of ''always'' telling people what you think about them, they can lead to awkward or unpleasant situations. It may harm your relationship with the other person if they don't like what you think, or they may reply without concern for ''your'' feelings or other considerations. Keeping negative thoughts to yourself or telling "white lies" can be considered a better alternative in some situations.
|-
|Replying to spammers||Clicking on the "Reply" button from spam mails and writing (and sending) a reply (or worse, clicking on the links in these mails)||--||--||At best, you confirm your email address and identify yourself as someone likely to respond to such unsolicited messages, and so encourage the spammers to deluge you with even more messages. At worst, the spammer may use your correspondence to extract sensitive information about you, or make you victim to a scam.
|-
|Solar cars||Having {{w|Solar panel|solar panels}} on the car's surface (mostly hood and roof) for power generation||+++||-||Cars require large amounts of energy in short periods of time and portable solar panels generally do not produce enough, nor are they as efficient as fixed installations on the power grid.
There are competitions for solar powered cars, though, like the {{w|World Solar Challenge}}.
|-
|Heelies||{{w|Heelys}} are shoes with a inline skate wheel embedded in the sole, at the heel. ||+||-||Heelys allow the wearer (usually children) to shift between normal walking and rolling like a roller skate. This sounds like fun but has led to numerous injuries.{{Actual citation needed}}
|-
|Prequels||A work of fiction (mostly movie) telling the "story before the story" of another work of fiction.||+++||-||More of a good story sounds great on the surface, but the constraints of a prequel's ending needing to create the starting conditions of the original work often precludes organic development and causes contrived plots.
|-
|Transition Lenses||A brand name for {{w|Photochromic_lens|photochromic lenses}} in glasses, which get darker (like sunglasses) in bright light.||+||-||Photochromic lenses are clear lenses that darken when exposed to UV light, then turn clear again when the exposure is removed. The advantage is that wearers of glasses don't need to buy separate (prescription) sunglasses. However, the process is relatively slow (about a minute) so not so useful when there is a quick succession of shade and bright light, perhaps in a forest or when driving. Also, car windscreen filter out UV light to some degree, which prevents the glasses from darkening as required. Finally, the process is temperature dependent, so in hot weather the glasses don't become as dark and in cold weather they might stay dark for too long.
|-
|Cutting pizza in squares||Cutting (a presumably round) pizza in squares||-||-||Most people cut pizza into wedges and hold it by the crust. Cutting it into squares allows for more pieces to be shared, but pieces near the center will have no crust to hold it by, getting cheese and sauce all over your fingers. There will also be lots of leftover tiny pieces. While hardly a disaster like the other items in its quadrant, square pizza pieces are just not very useful and rather inefficient. Cutting a rectangular pizza into squares might not suffer from the problems above, but, unless the pizza itself is square and cut only into four squares, some people will end up with a higher crust-to-topping ratio than others.
|-
|{{w|Project Orion (nuclear propulsion)|Project Orion}}||Study by the U.S. government looking into nuclear pulse propulsion for spacecraft.||---||-||Using repeated nuclear explosions to generate motion sounds bad for both the spacecraft and everything else, especially with a ground launch, but there are ways to address a lot of the concerns, so it isn't as bad as it sounds. Project Orion's theorized specific impulse and thrust would also be far higher than anything chemical rockets can accomplish. The efficiency of Project Orion is extremely low, however.
|-
|Soup||Soup||0 (neutral)||0 (neutral)||Soup is probably one of the oldest foods created by prehistoric cooks. Many people enjoy it, though some consider many soups somewhat lacking as a meal on their own, or bland.
|-
|Combo washer dryers||A device which combines washing machine and laundry dryer into one device||+++||+||Better at space efficiency, but worse at each task than separate devices.
|-
|Cutting sandwiches diagonally||Cutting sandwiches diagonally||+||+||Generally regarded{{Actual citation needed}} as the structurally superior way to slice a sandwich, providing better support in the hand and fewer all-crust bites. Required in the assembly of a club sandwich, where the diagonal components are stacked again.
|-
|{{w|Diverging diamond interchange|Diverging diamond interchanges}}||Road junction where the two (sets of) lanes cross over to switch sides (so if you normally drive on the right, now you drive on the left), then switch back to normal after the junction||-||+||Highway engineers believe the shape improves safety and traffic flow through the interchange because switching to the other side facilitates merging to and from the other road in the junction. However the shape appears to be insanity to an unfamiliar driver.
|-
|Toasting sandwiches||Making a sandwich first and then cooking it, as in a dedicated {{w|Pie_iron|sandwich toaster}}, a {{w|toaster oven|toaster oven}} or frying pan, or under a grill.||++||++||The grilled cheese sandwich is a familiar form to most people, and many other sandwiches are improved by toasting as a final step. Others, such as the {{w|western sandwich|Western}} or {{w|club sandwich|club}} are prepared using toast. The {{w|peanut butter, banana and bacon sandwich|Elvis}} is a specific case of a sandwich that normally wouldn't be toasted, but is improved by it - peanut butter, bacon, banana, and jelly, with the assembly lightly fried.
|-
|Crumple zones||Designated areas of a car that crumple in case of a crash... ||--||++||...to absorb the energy of the crash to prevent damage to the passengers. This goes against the intuition that having a section of the vehicle deliberately collapse during a collision appears to reduce the protection for the occupants.
|-
|Sliced bread||Bread, sliced by the baker before packaging for sale||+++||++||It's far more convenient for making sandwiches or toast, but unfortunately pre-sliced bread will go stale faster and some applications may be better off thicker or thinner than the slices provided. Sliced bread is often used as a comparator for how good something is in the phrase 'the best thing since sliced bread'.
|-
|Pizza||Flat, though usually leavened, bread with tomato sauce, cheese, and often vegetables or preserved meats||++||++||Pizza is a widely popular dish throughout much of the world, uncontroversial {{w|Anchovies_as_food|except}} {{w|Pineapple|certain}} [https://www.taste.com.au/recipes/nutty-choc-pizza-fresh-berries/2c0220a4-8463-45ff-b2ba-ac7e5012a006 toppings].
|-
|Eating citrus fruit while at sea||||0 (neutral)||+++||The vitamin C present in some citrus fruits prevents one from developing {{w|Scurvy|scurvy}}.
|-
|Putting mold on infections||Seemingly a reference to ancient practice of pressing moldy bread against infected wounds||---||++||While this sounds like a good way to get a fungal infection, with the correct mold this is a primitive antibiotic, and led to the discovery of penicillin.
|-
|Wheels on luggage||Some luggage bags have small wheels inset on their frame and a carrying handle.||+++||+++||A relatively simple fitting for rigid or semi-rigid luggage that substantially eases its transport over long distances on flat surfaces such as travel terminals.
|-
|Heat pumps||Refrigeration (or air conditioning) technology operated in reverse to heat an area instead.||++||+++||Because refrigeration is a very efficient way to move heat (as long as the cold side's temperature is high enough) this is often far more energetically efficient than directly heating a space. Reversible heat pumps also exist which can take care of both temperature needs in some climates.
|-
|Laser eye surgery||Surgical techniques using lasers for precision cutting in the eyeball.||-||+++||This technology has substantially improved the eyesight of millions of people worldwide by allowing treatment of eye problems otherwise only corrected by lenses, or entirely untreatable. Randall has previously commented on laser eye surgery, amongst other ideas both good and bad, in [[1681: Laser Products]].
|-
|Fecal transplants||Transfer of gut microbiome of healthy person to sterilised gut of ill person.||---||+++||The gut microbiome is a collection of bacteria that lives in our guts. It can influence our health. It is responsible for last stages of digesting our food. It can also produce neurotransmitters that are carried by blood to our brain influencing our behaviour. A healthy microbiome can be destroyed by bad eating habits, unhealthy lifestyle, infections or antibiotics. The important part is a composition of different species of bacteria that compromise the biome. Sometimes it may be necessary to completely sterilise the gut and then take a sample of a healthy biome from another person. A sample is enough as the bacteria will multiply. As long as the patient eats correctly, the microbiome after transplant should develop correctly.

It sounds bad because we tend to think of our feces as something gross, to be discarded. It is called fecal transplant as our feces contain about 50% of gut bacteria, but nowadays the sample usually takes the form of a coated pill that is applied rectally.
|-
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

{{comic discussion}}
[[Category:Charts]]

2923: Scary Triangles

2024-04-23T11:08:40Z

172.70.85.241: /* Explanation */

{{comic
| number = 2923
| date = April 22, 2024
| title = Scary Triangles
| image = scary_triangles_2x.png
| imagesize = 303x369px
| noexpand = true
| titletext = Concealed mostly beneath the surface, sharks are the icebergs of the sea.
}}

==Explanation==
{{incomplete|Created by the [http://www.atlanticconservationpartnership.com/conservation-research/bermuda-shark-project Bermuda Triangle] of the sea - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
[[Cueball]] is giving a marine biology lecture about sharks and seems to have mixed up icebergs with the topic.

In pop culture, {{w|shark}}s will often approach prey or people with only their front {{w|dorsal fin}} visible, which looks like a triangle, above the water. As far as prey are concerned, this is inaccurate, as most sharks will attack from below to keep the element of surprise.

In the comic the joke is that Cueball reveals that marine biologists have only recently learned that the triangle is only a small part of a shark. Until this revelation people were only aware of the visible portion, and the fact that death and injury often occurred when they arrive, causing them to be known as 'scary triangles'. Finally the community has learned that more than 90% (i.e. the rest of the shark's body) is hidden beneath the surface. (In most, if not all, cases it would actually be ''significantly'' more than 90%.)

The 90% is borrowed from an often cited factoid about {{w|iceberg}}s: that 90% of their volume is underwater. (This would be true for clean ice in freshwater, but in reality icebergs are filled with air cavities and float in salt water, so although most of an iceberg is beneath the surface, it is somewhat less than 90%.) Having learned that a similar fact is true of sharks, Cueball has drawn a dotted outline of the shark's body, equivalent to that often depicted in diagrams of icebergs, beneath the scary triangular fin, to show what a shark looks under the surface.

The title text continues the joke explicitly, saying that sharks are the icebergs of the sea. However, icebergs are already in, and thus also of, the sea, so icebergs would be the icebergs of the sea.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Cueball points with a stick to a poster behind him that has a diagram of a shark in the water with some unreadable labels pointing to its dorsal fin and gills. The outlines of the shark under the water are in dashed lines.]
:Cueball: Today's marine biology lecture is on '''sharks'''. We all know them as the scary triangles of the sea, but recent research has revealed that the triangle is only a small portion of the shark - over 90% of it is hidden beneath the surface.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Biology]]
[[Category:Sharks]]

Category:Major characters

2023-11-30T01:37:35Z

172.70.85.241: Undo revision 329870 by 172.71.151.119 (talk) Clearly you *could* edit. But as you're mixing this up with a forum/netnews thing, I'm not sure it's a correct edit, anyway.

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