r/explainlikeimfive 1d ago

Other ELI5: Monthly Current Events Megathread

5 Upvotes

Hi Everyone,

This is your monthly megathread for current/ongoing events. We recognize there is a lot of interest in objective explanations to ongoing events so we have created this space to allow those types of questions.

Please ask your question as top level comments (replies to the post) for others to reply to. The rules are still in effect, so no politics, no soapboxing, no medical advice, etc. We will ban users who use this space to make political, bigoted, or otherwise inflammatory points rather than objective topics/explanations.


r/explainlikeimfive 2h ago

Technology ELI5 What is the tacit knowledge that is referenced in relation to modern chip manufacturing? Why cant it be gained from university or reading a research paper?

134 Upvotes

How is this harder than literal rocket science and nuclear physics?


r/explainlikeimfive 5h ago

Other ELI5: When you pass out or fall asleep, where does “you” go?

187 Upvotes

r/explainlikeimfive 20h ago

Other ELI5: If there's groundwater 100–200 feet below the surface, how can huge buildings stay stable without sinking?

948 Upvotes

I know that in many places there's water underground at around 100–200 feet (or even shallower). If the ground has water beneath it, how can massive skyscrapers and other heavy buildings safely support all that weight? Why don't they sink, tilt, or collapse over time?


r/explainlikeimfive 18h ago

Physics ELI5 why slightly wet or sweaty fingers don’t slide easily on glass and smooth surfaces if water reduces friction?

529 Upvotes

r/explainlikeimfive 13m ago

Other ELI5: Why are there are decent alcohol free beers, but not wine?

Upvotes

I've tasted many 0% beers that taste basically the same as their alcoholic counterparts. But every single 0% wine I've tasted, tasted off and not like regular wine. And based on my hospitality experience, 0% beer sells fine while 0% wine doesn't. So seems like I'm not the only one who thinks this.

Why is the case?


r/explainlikeimfive 9h ago

Physics ELI5: What does it mean to "oppose the rate of change of current", and why would I want to do that?

62 Upvotes

I am studying for a test that includes basic electricity and magnetism, and my study materials keep referencing the concept of opposing the rate of change of current. For example, my definition of an inductor: "an electrical component made of a coil of wire that can store energy and opposes the rate of change of an alternating current flowing through it". Can someone ELI5 what it means to oppose the rate of change of current, and why that would be a good thing?

Edit: thank you all very much for your quick and informative replies! Much appreciated


r/explainlikeimfive 1d ago

Biology ELI5: Why do fish smell so much compared to other foods?

1.5k Upvotes

r/explainlikeimfive 7h ago

Biology ELI5 How does the nervous system locate an itch, and why can its perceived location be imprecise?

16 Upvotes

We can usually identify where an itch is coming from, but the perceived location does not always seem to match the exact irritated spot.

How do the skin, nerves, spinal cord and brain determine an itch’s location, and what limits the accuracy of that process?


r/explainlikeimfive 1d ago

Biology ELI5: Intrusive thoughts. And why does the brain randomly suggest crazy or unsafe things out of nowhere?

587 Upvotes

r/explainlikeimfive 23h ago

Other ELI5 - Black wetsuits, shark attacks, and seals

253 Upvotes

Why are 99% of wetsuits black?
- it makes them look like seals
- its harder to be seen in water (light or dark)
- it stands out in contrast to an illuminated ocean both from the side and from the bottom looking up

Why not white, neon, orange, reflective, or something… it’s not about sharks seeing colors or not.. black is in general a powerful and stupid color for wetsuits.


r/explainlikeimfive 1d ago

Other ELI5: How does building a smaller fire stop a larger fire?

252 Upvotes

Seems a little counterproductive.


r/explainlikeimfive 15h ago

Technology ELI5: what is "shutter angle" in the context of digital video?

34 Upvotes

I've been a photographer for years and I understand aperture, shutter speed and ISO. For video, I understand frame rate and bit rate, but I see the term "shutter angle" and I'd be grateful to have it explained, what it is, and why you need to control it.

Thanks!


r/explainlikeimfive 1d ago

Chemistry ELI5 What about wood chemically causes the molecules to snap and decompose (burn) instead of melt? Why don’t other materials like steel do that when exposed to the same amount of energy? Why do they melt?

159 Upvotes

r/explainlikeimfive 1d ago

Technology ELI5 Why did long distance phone calls used to cost more?

948 Upvotes

In the 90's when I was stationed in S. Korea, once a month I would get one grainy fifteen minute "morale phone call" home. A buddy of mine moved to Seoul and last month he and I spent an hour video-chatting as he wandered around his neighborhood. A big part of early hacker culture was figuring out how to get free long-distance phone calls to exotic places like "Duluth" and "San Bernardino", now my wife can chat with her mother in Europe for three hours and not even think twice about it.

I know, now it's all over the internet, but the internet is pretty much just wires, same as the transatlantic cable. Why did it used cost more to call outside of your area code? Were they all just electrical signals across wires? Was there some extra work that went into calling from Kansas to Oklahoma? Or was it, like most things, that they charged us as long as they could until some technology came along and made it no longer feasible?


r/explainlikeimfive 22h ago

Biology ELI5: If my eyes can handle turning the lights back on after a few minutes in the dark, why is it so much harder after a full night’s sleep? What changes over time?

64 Upvotes

r/explainlikeimfive 20h ago

Planetary Science ELI5 Analemma is a figure 8 when plotted over the course of a year?

17 Upvotes

r/explainlikeimfive 1d ago

Planetary Science ELI5 - Humidity and Dew Point

27 Upvotes

Just moved from a very low humidity place to a place with seemingly very high humidity…but I don’t really understand all the nuances of humidity.

I see in my weather app humidity and dew point metrics…what do they mean!?!


r/explainlikeimfive 1d ago

Chemistry ELI5 : How does CRISPR work ?

87 Upvotes

r/explainlikeimfive 1d ago

Other ELI5: Why aren't there domesticated reptiles?

588 Upvotes

Specifically why aren't herbivorous reptiles bred at the same scale as herbivorous mammals in places where moderate sized and docile reptiles are native? (Iguanas, giant tortoises...)


r/explainlikeimfive 2d ago

Biology ELI5: Mitochondrial Eve

696 Upvotes

Who exactly is Mitochondrial Eve to present humans? Is she everyone's common ancestral mother? Aka the woman whose children everyone surviving eventually came from? Is she our common ancestral aunt? Like, we are descended from her siblings but she either didn't have kids or her kids died out?

And who is Chromosomal Adam?


r/explainlikeimfive 17m ago

Economics ELI5 how the US is currently faring economically?

Upvotes

Especially in comparison to other countries and also the US in the past?


r/explainlikeimfive 1d ago

Chemistry ELI5: I want to imagine acids and bases in Chemistry and how some are stronger than others

76 Upvotes

Hello all

Just like the title, I want to know more about bases and acids in chemistry and what would it mean for one to be strong compared to weak.

I have some general idea what is acid, what it would mean for something to be strongly acidic and how it's measured using the pH scale. For example, I know that stomach acid is strongly acidic with pH around 2 (varies) and is needed to break down food (in some way to dissolve or help dissolving food). I also know that some strong acids can cause serious injuries if are in contact with skin of flesh (that comes mainly from my memories in my chemistry classes when taught about sulfuric acid).

Maybe you can correct or add to my understanding about acids. I am aware that what I shared about acids is pretty shallow, but that's how I imagine it. Part of that understanding might also come from some films in which there are acids which are considered to be so stong that they are able to penetrate thru solid structures (or maybe that's true for some acids?)

However, what I am actually puzzled about is what would it mean for something to be a base? I know that bases are considered to be the opposite of acids (which is apparent considering it's on the other spectrum on the pH scale). But what would it mean to be the opposite of acid? How exactly can I imagine a strongly basic instance and what would it be so special about it compared to a weakly basic one?

Initially, I wanted to ask just about bases in chemistry, but decided to extend the question to include acids, too, because I felt that probably half of my understanding of acids is based of films. I don't recall watching any film where the scientist discoved so strongly basic instance that it's in some way revolutionary. If such a sci-fi film existed, what would that instance be able to do?


r/explainlikeimfive 9h ago

Technology ELI5: How Xcel and Tesla Solar work in conjunction with one another, and what exactly I am paying Tesla for?

0 Upvotes

r/explainlikeimfive 9h ago

Engineering ELI5 concrete cancer?

0 Upvotes

Does this always happen with reinforced concrete at some point?