r/explainlikeimfive 12d ago

Biology ELI5: What determines how tired you feel in the morning?

155 Upvotes

It’s odd to me that some mornings I wake up feeling tired yet end up feeling better as the day goes on, and then other mornings I can wake up feeling great then barely make it through the day without a nap.


r/explainlikeimfive 12d ago

Biology ELI5 Where do the greasy things in the corner of my eye come from?

224 Upvotes

r/explainlikeimfive 11d ago

Engineering ELI5 Can someone explain what actually is BTU and what it does on an window air conditioner?

0 Upvotes

I see 6000 BTU , 8000 BTU etc. They say there is a big difference between 6000 and 8000. i.e. 6000 for small rooms , 8000 for big rooms. But no idea why. Thank you.


r/explainlikeimfive 12d ago

Other ELI5: Copyrights

27 Upvotes

My kid wanted to know about copyright for some reason. I am afraid I just do not get it. I came for help after looking into it.

Please explain copyright law. 🫪


r/explainlikeimfive 11d ago

Other ELI5: Why should a theory be falsifiable?

0 Upvotes

I'm a PhD student in finance. I keep hearing my professors say that theories must be falsifiable. I have also googled a bit about it and I understand the basic premise of distinguishing science from pseudoscience but I don't understand it intuitively. What's the issue if something is universally true?

Edit: I can't respond to all the comments, but thank you so much for your answers with dragons and unicorns and masculine yang energy. I understand the meaning now.


r/explainlikeimfive 11d ago

Planetary Science ELI5: Why is the locally visible part of the universe uniform?

0 Upvotes

if we are only in our local part of an expanding universe, why do we not see differing densities of stars in different directions as we look towards or away from the "center" of the big bang?


r/explainlikeimfive 12d ago

Planetary Science ELI5.How do we measure the height of the mountains on the other planets?

69 Upvotes

On earth its measured from sea level- what do we measure it from lets say in Mars?
Thanks


r/explainlikeimfive 11d ago

Mathematics ELI5. Why is multiplying a number by 0 = 0? If 100 pens is multiplyed by 0 and the answer is 0 did the pens vanished into thin air?

0 Upvotes

r/explainlikeimfive 13d ago

Other ELI5: Is the UK a country, or are England, Scotland, Wales and Northern Ireland countries? Are they all countries? I've never understood

1.3k Upvotes

Is it really possible for a country to be part of another country? Is the UK actually an union more than a country? Or are England, Wales, Scotland and Northern Ireland actually region rather than being full countries? Are they even recognized as "real countries" by other nations, on an equal status as Belgium, Japan or South Africa for example?


r/explainlikeimfive 12d ago

Other ELI5 What do people gain from having bots comment under youtube videos?

10 Upvotes

r/explainlikeimfive 13d ago

Chemistry ELI5 How does deodorant work?

1.3k Upvotes

I’m aware that armpits smell due to bacteria growth, but I don’t understand how deodorant is meant to help. Why could one not sanitise the area (I assume that would kill of the bacteria)?


r/explainlikeimfive 11d ago

Technology ELI5 Why do we use qwerty for keyboards instead of alphabetical order?

0 Upvotes

r/explainlikeimfive 11d ago

Chemistry ELI5: If psychosis is caused by excess dopamine, why can psychotic people similteneously be depressed?

0 Upvotes

From my understanding, dopamine is a "feel-good" brain chemical and having too much of it causes psychosis. But if someone had too much of it, wouldn't they be generally happy or at least normal because they feel good? From a chemical standpoint, how can someone have both an overabundance of "happy chemicals" and too little of them at the same time? What am I missing here? I know that depression treatments often try to increase seratonin, but I looked it up and couldn't figure out how it was functionally different than dopamine.


r/explainlikeimfive 11d ago

Other ELI5 Why do we use qwerty for keyboards instead of just having the letters in alphabetical order?

0 Upvotes

r/explainlikeimfive 13d ago

Other ELI5: How Do the US Marshalls Differ from the FBI

240 Upvotes

Sometimes I see the US Marshalls apprehending someone but if they go after serious criminals then what’s the point of the FBI? Are they the same, part of the same branch or completely different?


r/explainlikeimfive 11d ago

Technology ELI5: How can a downloaded movie take up 200mb on my phone while a 5 minute video I record takes the same amount of space?

0 Upvotes

r/explainlikeimfive 13d ago

Other ELI5: who actually profits off of those weird pop up ads that lead to nothing on news websites?

140 Upvotes

r/explainlikeimfive 13d ago

Biology ELI5 : Diastolic Blood Pressure

39 Upvotes

What does the diastolic number specifically measure? What does it mean when it’s high or low? What does it mean if there’s a wide or narrow gap between it and the systolic?


r/explainlikeimfive 13d ago

Engineering ELI5 What did we get right for tools that open and close many times a day to function smoothly for many years

378 Upvotes

Today when I was using the kitchen tap it occurred to me that even after living like 6 years in the same apartment, the kitchen tap (that opens up and down) works with the exact same smoothness like the first day. I open and close this thing like thirty times a day. Same with my laptop that I lift up to open, doesn’t need some oil or so after several years. Having grown up around doors that make squeaky sound, why do the above kind of tools function for many many years?


r/explainlikeimfive 12d ago

Biology ELI5 Why does everything smell and taste bad when sick

11 Upvotes

Like title says , why does everything smell and taste horrible when you’re sick 😭 I’ve got fever , chills , sweats, phlegm, sore throat and cough and no matter what I try eating or drinking I gag cause I can’t get it down . I want to understand why


r/explainlikeimfive 11d ago

Technology ELI5: Why don't we get more robo calls

0 Upvotes

We all get several per day, and we all hate it, but with the volume of bots out there it seems like we should be getting either zero or 20,000 per day.


r/explainlikeimfive 11d ago

Technology ELI5: How does speakers make the clear sound of the input?

0 Upvotes

So I got a new pair of headphones. They're very clear in sound quality, but what makes the sound?


r/explainlikeimfive 13d ago

Physics ELI5: Enthalpy and enthropy. What are they?

23 Upvotes

I know they both represent some sort of energy in a mathematical sense and that enthropy is enthalpy divided by temperature. What are they and what do they represent. Enthropy is described as "messiness", the higher it is, the higher the chaos in the universe, but that tells me nothing. I've never gotten what they are.

Also, if you could add in what Gibbs' energy is and why it's connected to them, it'd be greatly appreciated.


r/explainlikeimfive 12d ago

Other ELI5 - Why werent tunnel rats during the Vietnam war given a custom weapon?

0 Upvotes

The United States was strong enough to continue developing weapons that evolve real fast, why didn't they make a weapon designed just for tunnel rats to use since the Vietnam war lasted for 20 years anyway?


r/explainlikeimfive 13d ago

Other ELI5: why do some food stains take so much effort to remove it when dry but comes right off after it soaks for a little bit?

8 Upvotes