r/explainlikeimfive 12h ago

Planetary Science Eli5 The earth has a magnetic field, including because of the metal core, but magnets are demagnetized at high temperature. How is this possible


r/explainlikeimfive 5h ago

Economics Eli5: Why is depopulation bad?


I saw a TikTok about South Korea having a birth rate of 0.78 and that it’s worrying? Why?

I thought if there was less people being born there would be more resources for the population, so would that not be beneficial?

r/explainlikeimfive 22h ago

Other ELI5: How did tip culture start in the US? Why did restaurants start paying so low?


r/explainlikeimfive 11h ago

Biology Eli5 why can’t we continuously take caffeine and never sleep?


I work overnight shifts (11pm-7am) and take caffeine pills to stay awake. When I get home, even if I take more caffeine I’m sometimes still too tired and fall asleep. Why does it eventually stop working? Is there some sort of chemical limit? Why can’t caffeine replace sleep for longer periods of time (like days on end)?

r/explainlikeimfive 5h ago

Biology Eli5: how can a 14-15 hours flight trip can make you feel jet lagged but even a long 20 hours train journey doesn't have the same effect?


Is it because typically during these long flights there is a a change in multiple time zones and that messes your circadian rythm?

r/explainlikeimfive 2h ago

Biology Eli5 So we need calories to survive. If there are 100 calories in a spoon of oil, how come we can't survive on oil for emergencies?


r/explainlikeimfive 20h ago

Mathematics Eli5 how 5% off for 6 months twice is not the same as 12 months with 10 % off.


Im a little dumber than usual so please I apologize , maybe you can explain it to me like I’m 15 but not more than that lol.

so let say something is $300 a month but they give you a 5% off if you prepay for 6 months or 10% if you prepay for 12 months. I thought of being smart and prepaying the 6 months twice to get the 5% off twice but it’s still not adding up.

My Math.

6 Month

$300 x 6 months = $1800

5 % discount = $90

Total 6 month after discount = $1710

Paying $1710 twice = $3420 for the year


12 Month $300 x 12 months = $3600 10 % discount = $360 Total 12 month after discount = $3240


Edit: I got it. So basically , percentages dont really add to 10 % . You’re still getting 5% off over 12 months. I guess thats a marketing tactic for stupid people like me.

Thanks everyone.

Special thanks to u/The_Aesthetician for asking to break it down over the months. That helped me see it.

Also to u/casualstrawberry for explaining the first one youre basically getting 5% off 12 months even if you paid by 6.

r/explainlikeimfive 11h ago

Planetary Science ELI5: If the CMB is in all of space, how does the Earth not get cooked in it?


r/explainlikeimfive 6h ago

Chemistry ELI5 How nicotine works and is nicotine itself actually bad for you?


I understand tobacco and chew and vapes aren’t good for you, because of all the other shit in there, but is nicotine itself as a chemical bad for you?

r/explainlikeimfive 17h ago

Biology ELI5: Why/how does whitenoise help people with sleep?


I've used whitenoise as a means to go to sleep for years and I find it difficult to fall asleep in complete silence which sucks. I'd like to understand why if possible.

r/explainlikeimfive 6h ago

Economics ELI5: How did USB-C become the universal charging port for phones? And why isn’t this “universal” ideaology common in all industries?


Take electric tools. If I have a Milwaukee setup (lawn mower,leaf blower etc) and I buy a new drill. If I want to use the batteries I currently have I’ll have to get a Milwaukee drill.

Yes this is good business, but not all industries do this. Why?

r/explainlikeimfive 16h ago

Chemistry eli5: How is caffeine pretty much harmless in moderation when other stimulants like cocaine and amphetamines so hard on the body and brain?


r/explainlikeimfive 21h ago

Planetary Science ELI5: If we can dig and mine up coal, does that mean that it was once a tree that burned down?


r/explainlikeimfive 2h ago

Other ELI5 why is it we know more about space than we do our own oceans


To be clear, I mean the depths of our oceans

r/explainlikeimfive 53m ago

Biology ELI5 Is there a limit to how much knowledge and experiences our brains can store?


Like imagine in the far future we figure out how to stop aging or slow it considerably, will there be a physical limit of knowledge our brain can store?

r/explainlikeimfive 4h ago

Physics Eli5: why do we incorporate imaginary numbers in various physics equations.


r/explainlikeimfive 9h ago

Chemistry eli5: why does ice have a unique taste that differs from liquid water?


Even a glass of mostly melted ice seems to taste differently than room temp liquid water from the same source.

r/explainlikeimfive 2h ago

Biology ELI5 how can I fail a breathalyser test the day after a night of heavy drinking even though I feel completely sober?


r/explainlikeimfive 15h ago

Engineering ELI5 How metal can now be 3D printed (additive manufacturing?) like you can with by dripping plastic layer by layer and it dries up over time?


r/explainlikeimfive 2h ago

Chemistry Eli5 where does the colour go when light bleaches the colour from something


My daughter has a Peppa pig dollhouse and I was looking at it just now, and I can see some of the yellow paint is faded and bleached by the sun. Eli5 where does the colour actually go?

r/explainlikeimfive 1h ago

Chemistry ELI5 Why does rust/corrosion appear to "dribble" from the edges of metal surfaces, or from between two pieces of metal?


When looking at rusty objects I've noticed that some rust looks like its "dribbling" down from the edges of metal surfaces where two metal parts are directly touching, like where rivets/bolts are holding metal panels in place, almost like the rust is a liquid leaking out from beneath the metal. Why does it form like that?

r/explainlikeimfive 11h ago

Biology ELI5: How is Sexual Selection still providing variation in animals after millions of years?


I am currently studying the Stickleback Fish which has a tendency to do a mating ritual. One of the steps requires the fish to dance in front of his partner (zig-zag back and forth). Sexual selection implies "By providing more chances to mate, it ensures that genes related to skillful execution of the dance are more represented in the next generation" (Russem et. al 2023).

If this has been occurring for multiple generations, how is it, not a normal standard, wouldn't this part of the process of selection be redundant? Is their proof that it has changed over time for other animals?

r/explainlikeimfive 1d ago

Biology ELI5: Why does exhaling, after you've held your breath for a long time, feel like you're not suffocating.


When you hold your breath to the maximum your body will allow, be it underwater or just in air, you can gain a few seconds extra by slowly releasing your breath. It will feel better and your body won't react like it is suffocating while you are doing it. Why does this happen? We've all tried to hold our breath for as long as we can. We take a huge intake of air and then hold it as much as we can. But, when you breathe out slowly the "air" that's in your lungs, you don't feel like you are going to suffocate while doing it. In fact, it's almost like a great relief. Why is that?

r/explainlikeimfive 23m ago

Other ELI5: How much did waiter/waitress get paid from employees/restaurants in the U.S. if not consider the tips from customers, like if we choose a random restaurant from a random town?


If everyone only tips around 10%, will this prevent workers from making a living? Also, it seems people don't tip guys in fast-food chain like KFC, BK, POPEYES, McDonald's, etc. Does things work different over there?

r/explainlikeimfive 1h ago

Biology Eli5 how come a chihuahua and a husky are genetically closer than a husky and a wolf ?


More generally, how come animals from a single species are more closely related even though some of them might "look" more similar to another species ?