r/explainlikeimfive • • 16m ago

Other ELI5: How is language vocabulary formed and expanded?

• Upvotes

Who creates new words? I read somewhere that when enough people start calling something by a particular word, everyone accepts and follows. Looks ok for nouns like places, animals etc. but...

Let us take English as an example. Words like perseverance, assassination, fulcrum, pendulum etc. require some effort to form for the first time ever and propagate down the line. Words for language foundation required for communication. Who thinks about it and makes it for the first time? Is there any authorization required for a new word to enter a dictionary?


r/explainlikeimfive • • 56m ago

Biology ELI5: How does the human mind construct highly detailed realistic imagery of places a person has never actually seen in real life during sleep?

• Upvotes

r/explainlikeimfive • • 9h ago

Engineering ELI5: Why does driving just a little faster use so much more gas?

56 Upvotes

I've always wondered about this. If I'm driving 60 mph instead of 80 mph, I'm obviously going slower, but I'm also spending more time on the road. So why does driving faster end up burning so much more gas, even though you reach your destination sooner?I know wind resistance has something to do with it, but can someone explain how that actually works in simple terms?


r/explainlikeimfive • • 12h ago

Biology ELI5: why do people with albinism have shaking eyes?

111 Upvotes

what exactly is happening that makes them shake?


r/explainlikeimfive • • 13h ago

Other ELI5: How did Germany move away from Nazism after Hitler’s death?

1.2k Upvotes

r/explainlikeimfive • • 14h ago

Physics Eli5 the smallest "size" of a photon?

38 Upvotes

Is a single photon just the smallest possible wave of light in an EM field? And how did we discover that size?

So photons don't have mass and don't "take up space" in the sense that unlimited photons can be in the same space, but they can still be measured to have a "size"?

Is this like if I took a tape measure to a ghost, I could say it is 5' tall, but the ghost doesn't actually take up space( like it can go through me)?


r/explainlikeimfive • • 16h ago

Other ELI5: can bedding actually lower your body temperature, or does it just feel cooler?

58 Upvotes

I understand how a sheet can feel cool when you first touch it, but I’m confused about whether bedding can actually lower body temperature in any meaningful way. Is the feeling mostly caused by heat moving away from your skin faster for a short time, while room temperature and airflow still determine what happens later? I’m also wondering how moisture changes the feeling, since a fabric could feel comfortable when dry but different after several hours of sleep. Could someone explain the difference between initial coolness, heat transfer, breathability, and actual body-temperature regulation in simple terms? I’m asking how it works, not looking for a product recommendation.


r/explainlikeimfive • • 18h ago

Other ELI5: Why do women have discharge?

1.5k Upvotes

Possibly a dumb question, but my school / parents never taught about discharge. I actually spent years thinking I was broken because I didn't know what it was.

Obviously I know it's normal now and it changes throughout my cycle, but I don't think anyone ever explained to me why our bodies make it in the first place.

Is it basically the vagina cleaning itself? Does it have something to do with ovulation? ELI5


r/explainlikeimfive • • 18h ago

Mathematics ELI5: What does "hard" mean in NP-hard problem is as least as hard as NP problems.

0 Upvotes

What does "hard" here mean? I know that if all NP problems can be reduced to this problem in polynomial time, then this problem is NP-hard. But when you reduce a problem, don't you reduce it to a simple problem so that it's easier to solve 😂 So NP-hard is actually NP-easy?


r/explainlikeimfive • • 20h ago

Engineering ELI5 Why are batteries in phones measured in mAh and in cars it's kWh?

326 Upvotes

I get the difference between kilo and mini but why is one in Amps and other in Watts?


r/explainlikeimfive • • 1d ago

Biology ELI5: If steroids help keep your autoimmune system in check why not take them forever?

0 Upvotes

Basically what the title says. Why do you even need to go on and off steroids?


r/explainlikeimfive • • 1d ago

Other ELI5: Why, in Great Britain, are most B-roads (and many A-roads) lined with hedgerows on both sides?

0 Upvotes

The hedges completely eliminate the ability to see the beautiful surrounding land, and make every drive feel like you are trapped in a hallway. Is it a privacy thing? A wind-break? Simply historical tradition?

(American here, who enjoys wide-open views.)


r/explainlikeimfive • • 1d ago

Mathematics ELI5: what does Q-Max really measure in a sheet?

7 Upvotes

I understand that Q-Max is used to describe how cool a fabric feels on first contact, but I’m still not clear on what the number physically represents. Does a higher value mean heat leaves your skin faster in that first moment of touching the fabric, rather than the sheet staying cooler all night? I’m also trying to understand how two sheets can feel similarly cool at first but feel different later, once body heat, humidity, and the rest of the bedding are involved. Could someone explain the measurement with a simple everyday comparison, without turning it into a product recommendation?


r/explainlikeimfive • • 1d ago

Physics ELI5: How do mirrors work?

131 Upvotes

Intuitively, I thought it was light reflects off an object (like you) then reflects off the mirror then hits your eyes and you see it.

But then someone said it was the light just directly reflects off the mirror to then hit your eyes (nothing else like light from the sun hits the mirror then you) but that makes no sense because then you shouldn’t see the objects in front of the mirror in the mirror???


r/explainlikeimfive • • 1d ago

Mathematics ELI5: What are magic states?

0 Upvotes

I saw a post that Google solved magic states or somethig(?) and was wondering what it is


r/explainlikeimfive • • 1d ago

Other ELI5: Post Tax Deductions somehow saves money?

28 Upvotes

Hi, good morning. I'm uneducated in this discussion. I'm considered doing a Dependant Care FSA, which has a $5000 max per year($192.30/paycheck). This is a "Pre-Tax" Deduction.

I would then, as i understand it, pay the 383/week for Daycare, submit a request for reimbursement, and get that back. How exactly does this actually "save" money?

Secondly as a continuation, same thing for Roth IRA vs 401k?


r/explainlikeimfive • • 1d ago

Chemistry ELI5 How do charcoal filters stop smells?

95 Upvotes

r/explainlikeimfive • • 1d ago

Biology ELI5 How have the alligator and crocodile genus manage to survive tens of millions of years of what mother nature has thrown at them?

600 Upvotes

The earliest form is said to have started close to 85 million years ago, are the two species just that hardy?


r/explainlikeimfive • • 1d ago

Biology ELI5: What’s the TRUE benefit of washing your hands?

0 Upvotes

I just want to start this off by clarifying that I absolutely do wash my hands often, throughout the day. In addition to regular cases of hand-washing, like during cooking, or after using the bathroom, the nature of my job also causes me to wash my hands frequently.

But I’ve been wondering what it actually does. I’ve always assumed the point was to kill bacteria, but the more I learn, the less this makes sense.

Most soap is non-antibacterial, which is by design, because antibacterial soap kills all bacteria, not just the harmful bacteria you’re trying to get rid of. Antibacterial soap has its uses, but it’s not recommended to use as your daily hand soap.

Okay, so the soap doesn’t kill bacteria. It must be the hot water, right? You’re always told, from the time you’re a little kid, that hot water kills bacteria.

Except that doesn’t seem to be how it works in practice. In theory, yes, hot water kills bacteria starting at 149F. This is the minimum threshold; meaning at 148F, no bacteria is killed at all, and at 149F, bacteria starts to be killed, but still requires a 5 minute exposure time to effectively kill all bacteria. I don’t know a single person who washes their hands for 5 straight minutes. And this isn’t even to mention that the recommended max temperature for water heater manufacturers is only 120F-140F (at least in the US). That’s an entire 9-29 degrees below the minimum threshold.

So washing your hands at the highest possible temperature allowed by your water heater, for 5 straight minutes, still doesn’t kill any bacteria. On top of the soap that intentionally doesn’t kill bacteria either.

Am I missing something? Is killing bacteria not the point? Is the exfoliating effect from physically rubbing my hands together sufficient in getting rid of bacteria? That seems hard to believe. How is the raw chicken bacteria removed from my hand?


r/explainlikeimfive • • 1d ago

Mathematics ELI5: Linear Spans, Bases, and the Fundamental Theorem of Linear Algebra

0 Upvotes

Hello! I'm currently in university with an Informatics major, and today I had to take a 5-hour Linear Algebra lecture. I think I'm so cooked, so please help me. I think I more or less understand fields, groups, rings, and linear dependence, so that's my basis (no pun intended).


r/explainlikeimfive • • 1d ago

Physics ELI5: What are the 5 postulates of quantum mechanics?

0 Upvotes

I saw them mentioned in another thread, saying "If you simply accept them as 100% fact and don't think about it any more, the basics of quantum mechanics get significantly more intuitive". However, I can't find an easily accessible explanation. What are they? Who figured them out? Are they definitely true, or just our best guess at this point?


r/explainlikeimfive • • 2d ago

Other ELI5 How Cube match magic trick works?

91 Upvotes

I have seen magicians give a Rubik's Cube to a random audience member while keeping one for themselves. The audience member randomly scrambles their cube, and so does the magician. At the end, the patterns on both the audience member's cube and the magician's cube are exactly the same. How is this done?


r/explainlikeimfive • • 2d ago

Engineering ELI5 Where does the extra fuel consumption goes to, in cars with different cylinder capacity?

386 Upvotes

I drove around 500 kms with my friend. My car has a 1.6 engine; his has a 1.4. We went together, so roughly the same speed (around 110 km/h most of the time).

In that distance, my car consumed more gas than his (let's say, for example, 6 litres).

If that gas is not converted into speed, then what is it being used for? Heat? The engine is heavier, so it needs more gas to move it?

Thanks, and sorry for any mistake in my English.


r/explainlikeimfive • • 2d ago

Technology ELI5: What is DLSS?

0 Upvotes

I've seen people use it for work that's done using computer graphics and 3D but I don't know what that is other than it is neccesary to get an NVIDIA graphic card to plug that into your computer


r/explainlikeimfive • • 2d ago

Chemistry ELI5: If the iron in our blood is what makes it red, why is iron silver and not red?

989 Upvotes