ELI5: Why DO springs "return" back to their shape when stretched or squished?

Take for instance, a piece of metal wire, long and thin. Once bent out of shape, it stays that way


Plastic? Bend it, it stays out of shape, perhaps even shattering entirely if brittle enough


Springs on the other hand can be found made out of metal or plastic and when compressed OR stretched, the potential energy brings it back to its original shape in accordance with Hooke's Law


What exactly causes them to have a "saved shape" that they return to when deformed from a physics standpoint? Why don't they stay squished, compressed or shatter entirely?

https://redd.it/1rbjk5a
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ELI5: what is the “lump” in your throat when you’re nervous or anxious?



https://redd.it/1rgvtnu
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ELI5: What does Visa and Mastercard offer, and why is it so difficult to replicate by other countries?



https://redd.it/1rh2wpu
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ELI5: is there a base where pi could be a whole number?

Couldn’t we find a base where pi is whole and use that for calculations?

https://redd.it/1rgzvhi
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ELI5: What would happen if you skydived into a gas giant planet like Neptune while wearing a spacesuit? What kind of things would you see?



https://redd.it/1rh0uda
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ELI5: Why does Hershey’s (and other US chocolate) taste like “vomit” to others?

I grew up in the US and as someone with a big sweet tooth I always loved Hershey’s. It’s what I grew up on. I actually prefer it over what is considered “higher quality”.. I like the almost grittiness to it. The smoothness of “good” chocolate makes it less flavorful to me. It’s just like a hard solid smooth slightly sweet thing to bite on with a bit of cocoa flavor.

I’ve heard multiple people from the UK describe US chocolate as “vomity ” tasting, especially Hershey’s. Is there something specific about Hershey’s / US chocolate that makes it this way,? I don’t get that at all. Maybe I’m just blind to it atp.

https://redd.it/1rh8l2d
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ELI5: Why does everyone have a default smell that they can't smell themselves, but others can identify immediately when they enter your room or wear your clothes?



https://redd.it/1rhc0ef
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ELI5: Why do mental health problems usually appear in early adulthood?

I fell into a bit of a rabbit hole and a lot of mental health disorders seem to appear in early adulthood (18-25ish). I know the brain keeps developing until the mid-20s but surely it would be puberty where the most marked change in hormones etc would be the trigger. I looked it up but a lot of the research is in medical journals, which are quite difficult to read as someone with no experience navigating them.

https://redd.it/1rhdq8p
@r_explainmelikeimfive

ELI5: How does weight training help your knees??

Particularly in the context of running, I keep hearing you can help your knees (and even shins) by weight training (squats and all). How? How does strengthening the muscle help something bone and joint related?

https://redd.it/1rh49hh
@r_explainmelikeimfive

ELI5: Why/how is sugar a preservative?

It's easy to see how acid can help preserve food, and why salt doesn't "go bad", but what's the deal with sugar? I know that a jar of jam/jelly can grow mold, but I've never heard of jelly, jam or fruit preserves fostering bad bacteria like E. coli or botulism. How is it that the strawberry preserves can mold, but the sugar in the container on my counter never grows mold or bacteria, even when the weather is so humid that the sugar absorbs water from the air and sticks together?

https://redd.it/1rhdw0z
@r_explainmelikeimfive

ELI5: why does heating stuck screws, nuts, bolts etc make them easier to move?

I watch a lot of restoration videos and often when a screw, or nut, or other component is rusted and stuck, applying heat locally (like with a little blowtorch) can make it moveable again. I’m confused because I thought heat caused metal to expand and would wedge the thing in more tightly, but evidently that’s not the case - can someone explain what’s going on when heating a stuck metal part helps unstick it?! Thanks!

https://redd.it/1rh20fd
@r_explainmelikeimfive

ELI5 what is red light "therapy" and how does it work?

I have been seeing all kinds of different devices for red light therapy. Mats, face masks; things for pain, aging, you name it. There's also blue light thrown in at times. I just don't understand how lights help?

https://redd.it/1rhhjwb
@r_explainmelikeimfive

ELI5: does it actually matter what time you eat? if so, why?

started the year getting sick, made worse by my eating habits being really terrible. so i’m trying to fix that but like there is soo many rules and some of them make no sense to me.

one thing i keep seeing is that your kitchen should be closed after a certain time of day but i don’t get why?

on weekends where im not doing much i feel like i naturally fall into a routine of coffee/little breakfast, no lunch, dinner and then second littler portion of dinner or just a snack a few hours later then bed.

which i feel like is fine and probably better than lunch for me because im not hungry at lunch time and i am hungry at second dinner time and its bad to eat when you’re not hungry?

i dont know, explain it like im five please 🙂‍↕️

https://redd.it/1rhjfb0
@r_explainmelikeimfive

ELI5: can someone explain to me the reimann hypothesis as simply as possible?

For context of my math knowledge I am currently failing high school math

https://redd.it/1rhg1pz
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ELI5: if theres post exposure rabies treatment, why havent they found a cure yet?

Why does the vaccine you get after exposure work but theres no cure?

https://redd.it/1rhmnfh
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ELI5 : What happens if someone needs an emergency colonoscopy during an ER visit or other acute situation. They obviously aren't "prepped" with an empty colon. Can they clean out a bowel instantly if needed?



https://redd.it/1rhozgp
@r_explainmelikeimfive

ELI5: How do earthworms improve the quality of soil when they take nutrients out of it?

I'm curious as to why earthworms can eat soil, plant and animal matter from the ground and actually improve the quality of the soil with their droppings.

https://redd.it/1rhober
@r_explainmelikeimfive

ELI5: How do Beavers know to make dams?

My understanding is that this knowledge of making dams is innate and also connected/triggered by the sound of water. There is research to show that this behaviour is innate, where even an isolated Beaver will endeavour to make dams without having learnt it. How is this information passed from generation to generation? Do we know exactly how this process works?

https://redd.it/1rhpw4s
@r_explainmelikeimfive

ELI5: Why do our brains require "thinking time" when the information is already stored in it?

I've faced this multiple times. I'm writing an exam and I see a question who's answer I know but it just doesn't come to my head. I need to think for 15-20 seconds and then I remember it. Just now, I wanted to watch a youtuber's content but forgot their name. Took me like 1-2 minutes to finally remember it.
If the information is already in our brain, why wasn't it accessible during the first 1-2 minutes?

https://redd.it/1rhyc6q
@r_explainmelikeimfive

ELI5: Monthly Current Events Megathread

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.

https://redd.it/1ri2qcu
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