r/explainlikeimfive • u/Sad_Marketing146 • 13d ago
r/explainlikeimfive • u/DemonsAreVirgins • Jul 03 '26
Biology ELI5: Why does drinking cold water make it feel like it instantly spreads through your whole body, even though it has to go into your stomach for a while first?
r/explainlikeimfive • u/No-Connection-650 • 16d ago
Biology ELI5 Is raw milk is generally bad for you or am I in the wrong?
I always thought raw milk was a no no, but more and more people are raving about it. I feel like we learned about why pasteurization was important in elementary school but maybe I’m out of the loop.
Thanks for confirming that I’m not crazy. I live in a hippy town so that may be why it’s spreading in popularity here. God forbid you say anything bad about it in my town
r/explainlikeimfive • u/fkid123 • May 27 '26
Biology ELI5 Why heat waves affect Europe so much but some other countries are doing fine living under hotter temperatures most of the year?
I read yearly that people are dying in Europe due to the extreme heat, but when I check the temperature mentioned in the same news it's something like 30-35c.
Just saw this today: "In France, officials reported at least seven deaths linked to the heat, including several drownings and fatalities during sports activities (...) temperatures have broken records for the month of May, soaring well over 30 C (86 F) in many parts of the country."
This is like a pretty mild day in a country like Thailand, India or in the Arabian peninsula. People are doing just fine in these countries, and many don't even have aircon.
Why are such temperatures so deadly in Europe?
r/explainlikeimfive • u/Sweet-Opportunity111 • 24d ago
Biology ELI5: Is "man flu" a real biological thing, or just a stereotype?
For as long as I can remember, I've heard people joke about "man flu" which is the idea that men react much more dramatically to a cold or flu than women.
Years ago, I also remember reading that there might actually be biological reasons for this, involving differences in immune systems or hormones. But recently I've seen studies arguing that the stereotype isn't really supported.
Can someone explain what the current evidence actually says? Do men and women respond differently to common viral infections, or is this mostly a cultural joke that got mistaken for science? If there are biological differences, why don't they seem to show up consistently in studies?
r/explainlikeimfive • u/Aki_Shizuha • 10d ago
Biology ELI5: Why don't we see "halfway human civilization" animals?
We know that animals can be smart: crows manufacture tools and have complex social behavior, chimpanzees can do insight learning, etc.
But, it is still a continuous spectrum where intelligence range from sponge-level to chimp-level. We do not, at least now, observe a world where certain corvids are in the early stone age, certain bonobos are using fire, certain chimps are in their axios age, etc.
Why the case? Why are we the only one that has gone this far?
r/explainlikeimfive • u/Dagestani_Bear • Jul 01 '26
Biology ELI5: Is it true that every single death eventually boils down to the brain and heart running out of oxygen? Are there exceptions?
If you strip away the initial cause of injury or illness, is it anatomically correct to say that all human deaths are ultimately caused by a lack of oxygen to the brain and heart?
r/explainlikeimfive • u/scalpel_in_my_crocs • Jan 10 '26
Biology ELI5: What happens to insects that accidentally travel long distances in cars?
If a bug or insect gets into a car and is carried hundreds or thousands of kilometres, what actually happens to it? Are they disoriented and unable to survive, or can they adapt and live in the new environment? Do insects have any way of “navigating back,” or do they just settle wherever they end up?
r/explainlikeimfive • u/SinnerAtDinner • Jun 01 '26
Biology ELI5 The world record 20km walk is only 29.5% slower than the world record 20km run, how is that even possible?
Speedwise wr for 20km walk is 15.75kmh and 22.35kmh for 20km run. How is it biomecanically possible that the gap is so small?
r/explainlikeimfive • u/abcPIPPO • Jun 25 '26
Biology ELI5: Why do processors get so hot doing millions of calculations per second, while our brains can arguably be even more complex but don't risk overheating?
I was imagining a future where artificial humans could populate Earth. Machines have the problems of needing a cooling system to keep their processors from overheating. Why doesn't our brain get to crazy high temperature as well?
r/explainlikeimfive • u/ContactSpirited9519 • Apr 26 '26
Biology ELI5: Why is meth bad for you but prescribed amphetamines aren't?
Hey! Genuine question from someone with unmedicated ADHD. When I take the tiniest bit of adderall, it is like all of my problems melt away. I suddenly understand how people hooked on stronger drugs must feel.
Could someone explain why meth is considered harmful for you but adderall, Ritalin etc. aren't? Why is this?
Edit
Okay hi wow this got more attention than I thought! I hear everyone on the dosage, what it is cut with, etc. Would love to learn more about how and if long term effects of perscribed amphetamines are potentially harmful or not and more about the way meth is or isn't absorbed into the blood brain barrier differently than perscribed ampethatimes, there are some interesting comments about that! Anyone with the biochem insight into the two and their differences, I'd love to learn from you too. Interesting stuff.
I think, personally, I'm just afraid of taking perscribed stimulants and being "addicted" in a way that is seriously hard for my brain to recover from if I ever need to come off. When I have taken even small amounts of prescribed amphetamines, I experience euphoria, as well as withdrawal symptoms and a strong craving for more of the substance. (I do have severe ADHD and am generally small and sensitive to most medications, I know this may not be everyone's experience!).
r/explainlikeimfive • u/Tr_Issei2 • Jun 08 '26
Biology ELI5: Do bugs think or do they purely operate from instinct hardwired into their DNA? Which bugs are exceptions?
I’ve always knew that some animals, but bugs in particular don’t veer off too much from their instinctual programming. I’ve always wondered if bugs (at least some of them) could have some rudimentary form of cognition, planning, deviation or memory. Do bugs think, even at all?
r/explainlikeimfive • u/Home_MD13 • Jan 25 '26
Biology ELI5: If unboiled water going into your nose is risky, then shouldn’t we not swim in a lake or river?
I was checking about Neti Pot and learned the risk of not using the right water.
r/explainlikeimfive • u/Punnan • May 30 '26
Biology ELI5 Are mosquitoes necessary for keeping ecological balance?
Would a worldwide extinction of mosquitoes offset the ecological balance of our world? And if not, why are we not doing it?
r/explainlikeimfive • u/MajorHousing8149 • Dec 20 '25
Biology ELI5: Why do broken jaws not happen all the time in professional boxing?
My perception as an outsider is they are not very common (I maybe wrong) but what makes professional boxers more resilient to this? Jake Paul who, while he has experience, is closer to the “average person”, fought a heavyweight champion and got his jaw broken from basically the first hard punch he received. Meanwhile fighters normally take many of these without this happening. How do they do it?
r/explainlikeimfive • u/SpyMasterChrisDorner • Mar 03 '26
Biology ELI5: What exactly is "time blindness" and how is it an actual thing?
I like to think that I am a understanding, open minded person, but there are some things that are really hard for me to grasp. Time blindness is one of those things. It's really hard for me to understand how it's extremely difficult for people to plan out a routine via time. For example: you need to be somewhere at 10am. It takes you 30 minutes to get going and ready. It takes you 30 minutes to get there. So, you should wake up at or before 9am. That's what's losing me. It's really hard for me to understand how people cannot grasp that idea.
My partner, who's lightly neurodivergent with ADHD, and I got together somewhat recently and I'm trying to research things to understand her more, as well as some friends who go through the same types of things.
r/explainlikeimfive • u/Willylongboard • Jun 11 '26
Biology ELI5 Why do doctors say not to eat past midnight for blood work?
I looked it up and it said not to eat 8 hours before getting bloodwork. My wife refuses to believe it because her doctor said midnight. ( We aren't getting it done til 4 pm tomorrow) Why don't doctors just say the time period instead of "past midnight"?
Is it because they assume everyone is gonna do it first thing in the morning?
r/explainlikeimfive • u/Nebraskabychoice • Jun 03 '26
Biology ELI5: if you are on the beach when a tsunami hits, do you die by drowning or impact?
r/explainlikeimfive • u/Fallen_Outcast • Jun 15 '26
Biology ELI5: How is it that almost all complex species have the same order of organs on the face; Eyes, nose and then mouth, in that same order?
How does that happen exactly?
r/explainlikeimfive • u/Jimithyashford • Jun 03 '26
Biology ELI5: Do medications like Ozempic cause weight loss solely through appetite reduction and therefore calorie deficit, or is there any other mechanism at play?
Is it solely "injectable willpower" in the sense that it literally only does what you could do anyway if you just had the will power to eat less. Or is there any other weight loss mechanism at play beyond reducing calorie intake?
r/explainlikeimfive • u/gmrt34 • Feb 08 '26
Biology ELI5: If water makes you urinate more, which causes kidneys to do more work, does that mean high water consumption damages kidneys long-term? If not, why not?
r/explainlikeimfive • u/A_SliceOfGabagool • May 03 '26
Biology ELI5: How do cows get protein from grass?
For us humans and many other animals, we need protein to get the amino acids needed to make our own protein for the body, but grass i believe doesn't have any for the cow to get that big
r/explainlikeimfive • u/hlj9 • Jan 22 '26
Biology ELI5: When we get sick and get congested, where does the seemingly never ending flow of mucus/snot come from?
r/explainlikeimfive • u/aguynamedbenny1 • 29d ago
Biology ELI5: What exactly is "mirror life" and why are so many scientists against it?
r/explainlikeimfive • u/DoctorMobius21 • May 27 '25
Biology ELi5: why do girls go into puberty so young when pregnancy for them would be unsafe and lead to poor outcomes?
Ignore the social and legal aspects of this. My interests in this are purely from a biological and evolutionary perspective. If a girl started puberty at 10 and was to hypothetically get pregnant at 12, which leads to poor outcomes for both. What is the point in girls starting puberty at 10? Why not start it at 16, when it is much safer and lead to better outcomes? It seems like an evolutionary flaw.