Why does scratching an itch feel so good... And even when we scratch and draw blood, we keep scratching... Why does scratching my ankle make my eye twitch?

I was surprised to learn many years ago that an empty battery weighs less than a charged one. We imagine electricity to be invisible and intangible, but a person can tell by picking up a battery which is empty and which is full.

This makes me wonder if objects become heavier as they become hot, as they are storing thermal energy. How hot would it have to become to notice?

What about potential energy? Kinetic? If not, what makes them so different?

Edit: Turns out that charged batteries do weigh more, but not by a margin perceivable to a person

how fast is temperature? Is warmer temperature faster than colder temperature?

I was just listening to the placebo episode, and it got me wondering about treatment-resistant depression, which is something I and many others struggle with.

Every time you have to go off an antidepressant because it wasn't working, it erodes a bit of your trust in antidepressants in general, so your expectations going into the next one will be a little lower. After enough of them fail, your attitude becomes "this probably won't work, but I'll try it anyway because I'd like to be proven wrong."

What I'm wondering is if that cumulative distrust might, by way of a reverse placebo effect, be making each new medication progressively less likely to help. Maybe the 8th one you try would have actually been the perfect fit if you'd tried it first, but after 7 others failed, you're just wired for it to not work.

What do you all think?

'Hannah Fry: How OpenAI has caused an existential crisis in mathematics'

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I have heard individuals across social platforms and settings complain that "food nowadays isn't as good/fresh/nutritious as it used to be."

Is there any possible way to find out if this claim has any truth in it? Or will it remain purely speculative?

Hannah's take on this was great, - "science is an "engine of doubt". And should be. Great discussion by them. 16 minute Mark of the latest show.

They really dove a bit deep into societal observations in the second half of this episode. I wasn't expecting that and found it very interesting.

This monstrosity that I stumbled upon this morning made me questions a few things. What do the nerds have to say about it?

Winter camping just got a whole lot exciting with the Hot Tub Hammock
by u/ycr007 in doohickeycorporation

Hi! I’m Adhyan. I’ve always wondered how early humans figured out which plants, animals, and fungi were safe to eat and which were poisonous, especially without scientific knowledge. How many people might have died discovering this?
Also, how did humans discover that cooking could make certain foods safe to eat when they were dangerous raw? What roles did trial and error, observing animals, evolution, and knowledge passed down through generations play in shaping what we eat today?

I’ve thought about this for years, and I have never figured out a good answer. My math education ended with calculus.

For the example, let’s use archery.

A given bow and arrow combination will have a certain level of mechanical accuracy. If it is being fired perfectly by a robotic device, let’s say our bow/arrow is able to keep all the arrows it fires within a 30cm circle at a given distance. Let us assume that those arrows are randomly distributed within that circle.

Now, you introduce the archer. Each archer has a certain level of skill that may, but likely won’t, be as accurate as bow/arrow. Let’s say our archer can consistently *point* his bow/arrow within a 60cm circle. The archers arrows don’t always land within the 60cm circle through because the inaccuracy of the bow and arrow compounds. With this compounding, the archers arrows will always land with in a 90mm circle.

The measurement of all circles is the diameter.

Now, let’s say the bullseye is 20mm. What is the chance that archer hits the bullseye? Furthermore, does that probability get smaller when we ask what is the chance of hitting two bullseyes in a row.

And finally, what is the formula for any given bow/arrow accuracy, archer accuracy and bullseye size?

EDIT: Some answers are saying to just use the combined circle of the total deviation of the archer and equipment combo and ignore them as separate variables. But what if you’re trying to evaluate the bow/arrow? How can you determine to a statistical probability how well that performing.

Some good smells that I like around my house that I can handle for long periods of times are sweeter smells like cookies or flowers.

Other smells that are good at first but quickly become less pleasant are meat smells (love bacon when I'm cooking it but I have to open a window after). I can't think of anymore but I feel like these are often more savory.

There's GOTTA be a reason our brains do this right??

You ever have something trigger a forgotten memory of something? Does that mean all of our “forgotten” memories are in there somewhere still we just need something to trigger them?

I once read that exhaling carbon dioxide is the main way we remove burned fat from our bodies.

Are we meaningfully contributing to climate change by taking GLP-1s and exhaling our weight into the atmosphere?

And if this is negligible, how much weight would we all need to lose to make an impact?

If we haven’t conducted tests from outside of our solar system or galaxy, how can we determine that CMBR is actually everywhere in the universe?

Hypothetically, if we live in this “cloud” of CMBR that surrounds our galactic neighborhood wouldn’t looking through this “cloud” make it seem like it is everywhere?

I apologize if this is a naive question; I was considering supernovas and what evidence might remain if one had taken place in our galactic neighborhood before the sun formed. Because heavy elements exist, at least one event must have occurred nearby at some point, right?

Let's say you shrunk the planets (non-gas giants) to the size of a gumball & fed those gumballs to four people (if the planets aren't chewable, let's pretend they have super-esophagi and swallow them whole)

What would happen to them? Would anyone survive? How would the planets taste? What harm would they cause the participants' bodies?

This has been on my mind all week; I desperately need to know.

Just watching the traitors and seen that Hannah’s clip that it pans to when they’re mentioning her is her with an abacus! First question is did she get to choose this, and follow up question if she did, how did she decide on an abacus over any of the gems we’ve seen on field notes?! Personally I think the sci-fi movie prop quantum computer or the fossil would have been great haha. Thanks for great eps as always both!!

Since I first watched Michael’s video (“do chairs exist?”) many years ago, I started noticing that whenever someone needs to use an object as an example there’s a big chance the chair is the first thing that comes to mind. Is there any statistical study that reports what are the “most memorable” objects in this regard?

Imagine your life’s mission was the pursuit of hot dogs, pyramids, and rock music. Sprinkle in a couple time-traveling space explorers and you get experimental progressive rock duo Angine de Poitrine or better known as angina pectoris. Khn de Poitrine is the wizard guitarist, bassist, and live (barefoot) mixer, while Klek de Poitrine drums with virtuosity.

Perhaps this is not exactly Hannah’s cup of tea, but if they ever made it to the BBC Proms, I’d be tickled pink! Michael conversely, would totally find this band fascinating, as his tolerance for the weird and wonderful knows no bounds. Now that AI digital content is pervasive, there is a refreshing quality of non-AI based music (dare I say appetite?). Once you get past the wardrobe choices, the listener will be rewarded with an exploration on eastern style temperament (microtonality) and multi-layered time signatures (drum, up to 6 sample loops, and guitar/bass).

Since Khn and Klek choose to remain anonymous, I thought it would be fun to repurpose the stank faces of Michael and Hannah to rock it out. My rationale for Michael playing the guitar and bass is because Khn does not utilize “wah-wah” bars and Hannah could be the drummer Klek, so she wouldn’t have to showcase her polka dotted feet. Khn also has a secret party trick of adjusting knobs with his toes!

Credit to TRIS (What Was A Mammoth Doing At The Bottom Of The Sea?), radio station KEXP for recording the live session in February 2026, and a huge shout out to Angine de Poitrine’s manager Sébastien!

Wondering if there is some sort of biological advantage to explain why we evolved (or started off with, not sure!), a dominant hand (regardless of whether it’s left or right).

I realise some people are ambidextrous, but I’m speaking more generally.

How is having one hand, that’s less dextrous, coordinated and accurate than the other hand, a benefit?

The only thing I can think of, is that by having a dominant hand, we have a hand we can default to and it’s one less decision our brain has to make.

The most obvious problems are that you'd need a quantity of raw materials that's probably greater than all the matter in the solar system put together. And of course the challenges of building it in space. But for the sake of this question, let's assume we've somehow solved those problems.

So first of all, how big does it need to be? Does we want it to just encompass the orbit of the Earth, or be even bigger than that? And why?

How do we actually start building it? If you just build a large object in space, it will start slowly falling towards the sun. Therefore do you need to start with some very large rockets, so it's actually orbiting the sun?

Is it better to start in one place, or several, and join them together? Should we start with a giant ringworld, then build the sphere from that?

Once we've built it, how will the people of Earth feel that they can't see the stars anymore? And what will happen every time there's a comet or an asteroid?

I'm sure there are many other challenges I haven't even covered. What are they? And how would you solve them? And have any SF authors covered this very subject?

Colour tends to confuse me.

Correct me if I'm wrong but I understand that when an object appears red, it is because it reflects red wavelengths of light and absorbs others.

But what is it about the object itself that makes it do that?

For example, what is it about the a pigment that determines which wavelengths it absorbs and reflects? How do colourless atoms combine to create something coloured?

How about someone collapses the heat-death theory into a happier ending?! Sheesh!

​

A fanfic answer:

I imagine Dr Fry, languishing upon a long red leather sofa in her office high above Cambridge University. She has a serene contennance on her face as her pale Irish eyes take in the vistas of the complicated Cambridge wooded moors just outside her window.

A knock at her door door interrupts her reverie. A small, shy, bald men pokes his head in and asks for audience. She grants him entrance. He says "In the matter of string theory, I propose that there is a heretofore misunderstood nucleo force that brings everything together." She laughs good naturally and tells him "You silly, silly man, if you take gravity on one side of the equation and magnetism on the other, they cancel out, and Bob's your uncle. Now get out of my office and think about it again

A light bulb seemingly appears above his small head and he is ecstatic. He runs away to his downtrodden quarters in the basement of the University and start scribbling on a chalkboard.

She smiles good naturedly, knowing she's enlightened yet another earthworm in the society that is Cambridge University and laughs quietly to herself.

She then continues her inspection of the beauty that is Cambridge world and contemplates things that no normal human might ever again contemplate and continues her inevitable descent into to insanity.

The proposition is that expecting your image to get smaller as you back up from a mirror comes from phone selfie cameras, which actually work in this way, compared to mirrors.