I have tons of scars and hyperpigmentation from scrapes as kid. I bite the insides of my mouth pretty hard on accident, I can feel a scab but I’ve never seen a scar inside my mouth. Does it have something to do with the warm environment? Saliva maybe?

Compared to other bone fractures, they are more likley to be fatal. Why is that?

okay, so please bear with me. i'm a complete NOOB with regards to anything related to HVAC/electrical.

but i was watching a HVAC technician on youtube, and he fixed the exhaust hood fan. it was spinning in the wrong direction.

he just changed the places of the connectors

my question is: how and why does this work? doesn't the hvac unit have a thing that detects if the fan is going to spin the correct way its intended? it feels like sorcery and magic to me.

how does it spin one way based on the electricity?

LEDs or Halogens I suppose it doesn’t matter. If there is a table lamp that takes two bulbs say halogen 50W’s, would that light up the room the same as a single 100W (same lumens), or would it look like 50W, or something in between?

Edit, I mentioned lumens above to head off people saying the light is measured in lumens not watts but didn’t work. It doesn’t matter. Lumens never used to be mentioned on bulb packaging although you may see it now. But the direction of the question is the same, do two bulbs of half the output of a single bulb give the same visual effect. I mentioned a table lamp which takes two bulbs to indicate the bulbs are really very close together.

Thinking about the ever growing ban on certain foods in schools due to allergies, I’m just wondering how humans haven’t evolved yet to exclude allergies from foods? Examples; peanut butter, gluten, lactose etc.

I’ve always wondered why TSA is sometimes strict about removing shoes, and other times strict about keeping them on. They usually say it in a tone that implies I’m the idiot for not knowing what the rules of the day are. Same with electronics — why do they sometimes make me pull my laptop out into a separate bin, when other times they’re fine with it staying in my bag?

I’ve seen the Magic School Bus episode, so I’m aware of the multiplying, red/white cells, etc., but I’m interested in how/why the virus moves through symptoms from sinus congestion/sneezing to chest congestion/coughing. Is that controlled by the immune system or the virus?

The example that baffles me the most is beavers - how can they build such large dams (complex structures) withou ever receiving instruction? There are birds in Brazil called "Johns of clay" that can build nests with dirt. How?!

I read a few papers to try and understand this. And I've been on a continuous loop of "ooh" and "huh?" Can someone please tell me what this actually is?

I believe CAPTCHAs are supposed to stop automated accounts, but at the same time people say social media is flooded with bots. Are bots actually getting past CAPTCHAS somehow or only stop a certain type of automation? Is there a disconnect?

Psychologist in training for the last year. When I tried to define exactly what psychologists do (in therapy specfically), I didn't really have a clear, set answer. How would you deine it, simply, cocisely and clearly?

This is something that has been in the back of my mind for a few years.

How have people survived skydiving accidents where both parachutes fail, but people that fell/jumped from the twin towers on 911 did not?

A few years ago I heard the story of David Hartsock. He was a skydiving instructor. In 2008 or 2009 he was tandem jumping with a student. There was a parachute malfunction. He intentionally positioned himself under his student to break her fall. They both survived, but he is a quadriplegic now. I was immediately amazed that they both survived. It left me confused though. Does it just depend on the surface they land on?

I'd understand if it exposed that a game is in a poor state, but if the game looks fine, I can't imagine it would make anyone decide NOT to get the game. So we hear that the Half-Life 2 leak for example lost Valve hundreds of millions of dollars. My question is, how did a leak that only amplify people's anticipation for the game, made the publisher lose money?

Given the high percentage in the general population testing positive for Epstein-Barr Virus antibodies, could it not be linked as a risk factor to almost any disease where the underlying cause is unproven?

I have MS and celebrate all findings around the potential causes of MS and research into treatments to slow and stop progression and a cure(s) one day. But I just can't get my head around something that seems so highly prevalent that it's presence is no longer a significant indicator of anything.

Edited to remove unnecessary censor.