That you get out of a shower wetter than when you get out of a bath.
That you’re never fully in contact with anything you touch.
That all of Earth’s systems/cycles are finely in perfect balance to allow life.
I have just started a degree course in Physics so I can study quantum mechanics – I find it fascinating as it’s so counter intuitive as we experience a Newtonian universe on a day to day basis.
@olddog, not sure where you are but this Friday
https://www.npl.co.uk/open-day
Quantum mechanics, classical physics and engineering, and people pissing about with LN2 too.
CountZeroO
h, and by the way; Bumblebees – magic can be the only explanation for how something so fat with such tiny little wings actually fly?
Lovely little creatures, always bring a smile to my face as they, well, just bumble past.😁
They like a bit of football too.
It doesn’t make the boats any lighter.
Except, it does. You’ve got things which are much denser/heavier than water (steel) and things which are much less dense/heavy than water (air). Add them together and you’ll float or sink depending on whether you’re at a net gain or not.
These are concrete, so how do these work, then? 😝
I’m still amazed that superglue in a bottle doesn’t dry up
I'm not because I saw someone explaining how it sets. A lot of things don't set because they dry out, they undergo a chemical reaction which makes them solid - concrete, for example. The cement dissolves in the water then a chemical reaction happens to make a solid. If you let the water dry out before this reaction occurs it stays soft and crumbly. Cyanoacrylate needs water molecules to cause a chain reaction that polymerises it - that's why it sets so quickly and especially on your skin. That's why if you want to keep it fresh in the bottle or tube, squeeze all the air out - or get one of the squeezy sided bottles, as they do that.
Re boats, it's the entire volume of the boat below the surface that is the same weight as the equivalent volume of water. So it's the metal AND the air inside it that counts. If you push down on it, more of it is below the surface so it displaces more water than its volume - so when you let go it bobs back up to the point where the volume and weight are the same.
Think about it this way - when you put a boat in the sea, the sea level rises a little bit as your boat goes down - like a see-saw.
I find it fascinating as it’s so counter intuitive as we experience a Newtonian universe on a day to day basis
When I studied it there was no intuition involved. This is the equation, this is what it says about the relationship between those values. Intuition is based on your lived experiences of the macroscopic world, the quantum world is something else entirely. It's nothing to do with what you consider 'the world' to be.
I know it's probably quite a well known meme now, but this still blows my tiny mind a bit.
It deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe
Don’t think of it as the universe expanding, think of it as the amount of nothing getting smaller
I’m writing this down, it might come in handy someday!
still haven’t explained the induction hob.
Magnets. When in doubt, it's always magnets, aliens or DNS.
And I’m a bit smarter now than i was 15 mins ago……
No you're not. You're more knowledgeable, your smartness hasn't changed.
These are concrete, so how do these work, then?
But your photos suggest that they don't work.
Whose smart-arsed idea was it to build concrete boats?
On the boats thing, take a glass bowl and float it in a sink of water. Now melt it into a big marble and try and float in the sink again.
Seismic exploration - voodoo and etch-a-sketch mixed up. I used to tow several km of hydrophones* and the echoes were fainter than the noise of the waves. Add them all together and out pops some squiggles. Geologist gets the colouring pencils out and next thing half a billion dollars of oil rig has a gyser of black gold shooting out the top. And it was less than £1 a litre when I learnt to drive!
*Don't get me started on piezoelectricity
Resin 3D printers.
Boy1 has one. He models anitem in CAD software, transfers it to a machine that uses UV absorbing resin, fires UV light at it and a small 3D copy of the thing he created on his computer pops out.
I kind of understand it’s all about UV light, exposure time and intensity, movement and speed of the build plate. But it’s still witchcraft.
Time? Why does it fly when you’re having fun?
the acceleration of a piston from top dead center…….is accelerating at 15,000 ms^-2,
The acceleration is the easy bit, it's making sure they decelerate at TDC that's important 😉 Have watched a 4.2 litre V8 fail to decelerate a number of pistons... at 8000 rpm/full load.
And FWIW, the forces are high enough that the flex/clearances in the conrod/gudgeon pin/crank/block/frame of the engine are large enough to make a measurable difference in the peak loads. Even though the flex/clearances are minuscule.
That you get out of a shower wetter than when you get out of a bath.
Ooooooooooooh, i know this one!
The surface tension of the water in the bath is stronger than the adhesion of the water to your body.
So the bath sucks the liquid off. Don't get that effect in a shower.
(May not apply to those of us who are very hairy.)
And Rolls Royce Aerospace used to send their apprentices on a sailing trip as part of their training.
On a concrete sailing boat.
That sound of the orchestra – that IS just a series of vibrations, so that’s what’s on the record.
Yes I get that. But you could grab any fraction of a second of the recording and have dozens and dozens of instruments playing (on any record not just an orchestra) and a tiny series of bumps allows you to differentiate between the cellos, the violins, the tubs, the french horns, the cymbals,
Hair growth.
If you shave your head hair, it will grow then carry on growing and get longer and longer and longer.
If you shave your hair from anywhere else on the body it will grow to a fixed length then stop. No-one has 30cm long pubes (not even Hairy Helen from Stevenage who I was introduced to as a teenager)
How does body hair know when to stop growing?
But you could grab any fraction of a second of the recording and have dozens and dozens of instruments playing (on any record not just an orchestra) and a tiny series of bumps allows you to differentiate between the cellos, the violins, the tubs, the french horns, the cymbals,
All those sounds add together into a single wave. The clever bit is that your brain can recognise them all separately out of that single wave.
How does body hair know when to stop growing?
These are all the kinds of questions I've thought about and/or looked up since I was a child so I have plenty of answers (accuracy not guaranteed). Body hairs grow at a certain rate, and each follicle grows for a certain amount of time before ejecting its hair and starting again. That alone will result in a fixed length, but what also happens (especially for body hair) is that it rubs on your clothes and furniture etc so it gradually gets eroded. If you have a close look at an arm hair it tapers to the end - so the length is determined by the wear it gets, its toughness, how fast it grows and how long the follicle goes on for. With long head hair the ends fray, split and break up as well, which is why if you want to grow longer hair you need to trim these bits off or somehow stick the ends back together. They grow until they fall out and start again.
Bluetooth.
Tides.
Anything about the earths crust, rock formation, volcanism etc.
the forces are high enough that the flex/clearances in the conrod/gudgeon pin/crank/block/frame of the engine are large enough to make a measurable difference in the peak loads. Even though the flex/clearances are minuscule.
And yet metal-metal contact in the rods and crank are prevented by just pumping some oil between them.
take a glass bowl and float it in a sink of water. Now melt it into a big marble and try and float in the sink again.
Now drop it in a bowl of mercury.
Relative density can be counter-intuitive. If you have a loose helium balloon in a car and accelerate sharply, it will fly forwards.
Mercury - that it is a liquid at room temperature. Watching a lump of mercury melt looks like magic.
The internet.
Try and explain what it is now that it exists. Difficult isn't it?
Now pretend you are Tim Berners-Lee trying to explain what you have invented 30 years ago.......
And yet metal-metal contact in the rods and crank are prevented by just pumping some oil between them.
Yup, that's a whole new pile of complicated maths and "science". (Tribology, that i nearly did a degree in...)
Standard ones where my knees stick out and my torso from about sternum upwards - and my head obviously. I once rented a flat with a huge wide bath and one time I plugged the overflow and filled it right to the brim. My legs and arms floated, it was actually quite weird. How I didn't go through the floor Money Pit style I don't know because it was upstairs in a shonky old house.
The internet.
Try and explain what it is now that it exists. Difficult isn’t it?
Not at all. It's a network of computers connected across different geographical locations via IP routing.
Now pretend you are Tim Berners-Lee trying to explain what you have invented 30 years ago
As above, it's easy, but he didn't invent the internet he invented the world wide web, which is (or was when he invented it) a specific protocol and a markup language that embodies the concept of hyper linking. Pretty straightforward.
Next question.
@gecko76
Mirrors. A room with a mirror in it is fractionally colder than it would be without one. Measure it if you don’t believe me.What else do they steal, apart from heat?
Your soul........
I want to know what happens to the other me in the mirror when I'm not there - where does he go?, what does he do?
If you have a loose helium balloon in a car and accelerate sharply, it will fly forwards.
How do you know that?
How do you know that?
Errrr, personally speaking i've actually tried it...
And under braking (that was more noticeable in my 60bhp shitbox).
its not that the balloon with fly forwards, but all the more dense air in the car will "slosh" backwards, displacing it.
Another one for me, the fact that you can see through some materials and not others.
Errrr, personally speaking i’ve actually tried it…
Now there's dedication to expanding your scientific knowledge!
Don't try this at home! ... But you can float an iron anvil, in liquid mercury.
It's because the mercury is much more dense than iron.
Same principal applies to steel or concrete boats... They are mostly full of air so the gross density is less than that of water.
On the subject of how very small insects can 'fly'..they are not actually 'flying'.
They are less dense than the air around them so in the case of very small flying insects... It's more like they are swimming thorough the air, much like a human can swim through water.
What sort of weird-ass baths are you taking?
That reminds me of an XKCD:
This cartoon changed my life. Impossible to think otherwise now 😆
Don’t try this at home! … But you can float an iron anvil, in liquid mercury.
It’s because the mercury is much more dense than iron.
Old lighthouses used to float the entire lighting apparatus on a bath of mercury so that it could be spun round smoothly.
Vinyl records.
No idea how a series of bumps in some plastic can recreate the sound of a full philharmonic orchestra
Following bumps in plastic I can accept, it how you get stereo from a single stylus that blows my mind
how you get stereo from a single stylus that blows my mind
Is one horizontal and one vertical? (I don't know.)
Is one horizontal and one vertical? (I don’t know.)
I *think* that it's rather that, if you imagine the groove as a V-shape, the 'bumps' are on the inner sides of the V. The bumps on one side are the left channel, the bumps on the other side are the right channel.
How that is actually turned into music by running a needle across it is by magic though, obviously
On the subject of how very small insects can ‘fly’..they are not actually ‘flying’.
The urban legend that bumblebees (other bee species are available) shouldn't be able to fly according to the theory of flight is obvious bunkum. I mean, firstly, they they are; flying...and secondly, they don't fly in the sense of airplanes, that's true enough but they fly by creating vortices at their wingtip that propel them upwards, sort of slightly (but not really) helicopter-ish.
Is one horizontal and one vertical? (I don’t know.)
The coils are angled to either side so that if the needle moves upwards you get an even impulse through both channels, if it deflects up and diagonally left/right you get the stereo signal in either channel respectively. It's clever because it means if you put a mono record on a stereo turntable it'll still play, and vice versa.
Analogue color TV is similar in that respect.
The B&W signal is basically an AM signal so as it passes along each line amplitude = brightness.
The color signal is then overlayed on that (appearing as the sidebands if you do the Fourier transform of the wave function), but only red and blue are broadcast, it determines the green based on the first signal subtracting the 2nd two.
Which meant that even after colour TV was switched on you could still watch B&W programs on a colour TV, and old B&W TV's would still work perfectly.
If you see pictures of a TV gallery the Vision Engineer will still be looking at the same two scopes even though analogue is long past, a waveform monitor that shows the intensity of all the lines in the image as a graph, and a vectorscope that is a plot of each pixel's red and blue value, so to white balance something they just twiddle the red and blue knobs until it's a dot in the center of the scope. Whilst the exposure (aka "brightness" on your TV settings) is done by adjusting the gain on the waveform monitor to keep the lines within the limits, and black-balance (aka "contrast") is done by adding or subtracting form the overall signal which moves the lines up and down, the idea being you should allow the lines to just hit the 0 so you know the blacks are black without taking all the details out of the shadows.
The urban legend that bumblebees (other bee species are available) shouldn’t be able to fly according to the theory of flight is obvious bunkum.
Obvious bunkum because everyone can see bumblebees flying?
Definitely. But they do apparently defy known laws of aviation in terms of wing size relative to body size.
Jumping a push bike without crashing.
I think that they just didn't know how bees fly. They obviously do as any scientist can tell you.
Who you gonna believe....... your own lying eyes, or a scientist?
Apparently NASA has a poster which reads:
Aerodynamically, the bumble bee shouldn't be able to fly, but the bumble bee doesn't know it so it goes on flying anyway.
Apparently NASA has a poster which reads:
Aerodynamically, the bumble bee shouldn’t be able to fly, but the bumble bee doesn’t know it so it goes on flying anyway.
@nickc - 😝
Fun sponge!
Tiger Bread
But they do apparently defy known laws of aviation in terms of wing size relative to body size
No they don't. The mechanism by which insects like bumblebees fly is pretty well understood. If they tried to fly like an airplane, they couldn't, but as that's not the only way to achieve flight, it's irrelevant.
The coils are angled to either side so that if the needle moves upwards you get an even impulse through both channels, if it deflects up and diagonally left/right you get the stereo signal in either channel respectively. It’s clever because it means if you put a mono record on a stereo turntable it’ll still play, and vice versa.
Analogue color TV is similar in that respect.
The B&W signal is basically an AM signal so as it passes along each line amplitude = brightness.
The color signal is then overlayed on that (appearing as the sidebands if you do the Fourier transform of the wave function), but only red and blue are broadcast, it determines the green based on the first signal subtracting the 2nd two.
Which meant that even after colour TV was switched on you could still watch B&W programs on a colour TV, and old B&W TV’s would still work perfectly.
If you see pictures of a TV gallery the Vision Engineer will still be looking at the same two scopes even though analogue is long past, a waveform monitor that shows the intensity of all the lines in the image as a graph, and a vectorscope that is a plot of each pixel’s red and blue value, so to white balance something they just twiddle the red and blue knobs until it’s a dot in the center of the scope. Whilst the exposure (aka “brightness” on your TV settings) is done by adjusting the gain on the waveform monitor to keep the lines within the limits, and black-balance (aka “contrast”) is done by adding or subtracting form the overall signal which moves the lines up and down, the idea being you should allow the lines to just hit the 0 so you know the blacks are black without taking all the details out of the shadows.
I recognise most of those words, but not in that order.
But they do apparently defy known laws of aviation in terms of wing size relative to body size
No they don’t. The mechanism by which insects like bumblebees fly is pretty well understood. If they tried to fly like an airplane, they couldn’t, but as that’s not the only way to achieve flight, it’s irrelevant.
What if the bumble bee was on a treadmill?
I actually know the origin of the bumble bee myth...
It dates back to the development of sof****e by NASA to model aerodynamics of aircraft in the 70's or 80's, the software worked fine for the type of thing it was designed for (delta wings I think) but when someone tried to model a bumble bee it was unable to properly account for the way their wings generated lift from the vortexes. The result was the myth about bees and development of better software.
STOP EXPLAINING THE MAGIC THINGS!
It is the same thing with helicopters not being able to loop the loop. Everyone has known it since the early days of helicopters so no-one is tempted to kill themselves to prove it.
Then a helicopter company designed the software to help predict how helicopters would fly with different rotor lengths, counts,speed etc. One of the test engineers got bored and tried a loop the loop and it worked.
After checking the software was correct (a few times I should imagine) someone tried it is a real helicopter and it worked. Suddenly it was possible to loop the loop even though there were lots of explanations as to why it was not possible.
Basically, the explanations saying it was not possible had missed out something. That is why bees fly and helicoptors can loop the loop.
Chat gpt 4o when asked to answer this thread.
Sure, here are a few:
1. Quantum entanglement: It's like two particles communicating instantly regardless of distance, which seems pretty magical.
2. Black holes: Where gravity becomes so strong that not even light can escape. It's like an invisible force devouring everything around it.
3. Photosynthesis: Plants turning sunlight into energy seems almost like a spell from a wizard.
4. DNA: The blueprint for life encoded in molecules—it's like nature's own magical coding language.
5. Teleportation in quantum mechanics: Moving particles from one place to another without physically traveling through space—it's like something out of a sci-fi novel.
It is the same thing with helicopters not being able to loop the loop.
The Sikorsky test pilot back in the very early days of helicopters was the first to loop, back in 1949 (or thereabouts, I'd look it up, but y'know; Google that way) they even filmed it.
The reason helicopters didn't normally, is mostly to do with power to weight ratios. It's not until jet engines that were small enough and powerful enough started to get fitted routinely that people started doing aeros in helicopters, and that only started relatively recently. In the 50's to about the late 70's it was common for helicopters to have piston engines. They were sometimes not even powerful enough to get helicopters in the air (depending on weight and air density), let alone do manoeuvres like loops.
Might have been the jet helicopters I read about, then again, I did read it on the internet so...
You do need fancy swash plates that'll stand up to the stress. So if your helicopter's not powerful to do aeros, there's no need to build them so they can, right? So now they have good engines, rotor heads are built to take the stress and do the combined blade control that you need to perform stuff like rolls and loops and so on and to make it even easier, there's flight computers controlling all the moving parts these days.
their wings generated lift from the vortexes
Like Concorde landing. It doesn't have flaps, but the vortexes generated on the leading edge of the wing at high angles of attack make the wing appear bigger (longer camber) to the rest of the air flowing over it and so it can generate more slow speed lift. Downside is it creates drag and so it needed lots of thrust to land.
Has anyone mentioned the effect that gravity has on time?? If not why not??
I guess that's maybe because its not self evident. And as far as I'm concerned its beyond magic.
As you were.
photography related. Mrs McMad has recently got into cyanotype. Interesting and just about explainable, but she has just had a play with wet cyanotype. Watching the image change over a few hours is total magic.
If only uploading photos was easy. Here is an insta link for anyone interested
Has anyone mentioned the effect that gravity has on time?? If not why not??
https://www.npl.co.uk/news/time-dilation-demonstration
So not only do people in the C-suite on the top floor get paid more, they also work shorter hours. Double bastards!
can bumble bees loop the loop?
can bumble bees loop the loop?
The amount of bumble bees I find lying on their back and needing help to flip over would suggest not, but they do try.
But they could if they had titanium rotor heads.
The amount of bumble bees I find lying on their back and needing help to flip over would suggest not, but they do try.
That’s what happens when bumblebees do a victory roll having managed a loop, they’re so exhausted they can’t land properly.
It's lack of sunshine. Bumblebees are fueled by pollen, nectar, and sunshine.
Record Players.
Despite knowing exactly how they work, how can a metal needle in a plastic groove sound that good?
Dark arts.
Quantum entanglement!
NASAs recent strategies for doing stuff in space.
"So when we get to Mars we're going to use our pixie duat to let us hover while the lander is lowered on a thread of unicorn hair, then once it's down a baby lander will unfurl it's own wings and go off to explore"
Or
"we'll fly a long way from earth, then say the magic word and a tiny box will grow and grow until it's a massive solar panel, then we'll squish our eyes around until we can somehow see clearly and then we'll look at tiny bits of space send back some amazing photos"
Danny MacAskill
