Today I Learned
- Thread starter Greg Bernhardt
- Start date
Click For Summary
Today I learned that cleaning a white hat can be done with bleach cleaner, but it’s important to rinse it before wearing it again. I also discovered that "oyster veneering," a woodworking technique from the late 1600s, is experiencing a minor revival despite its labor-intensive nature. Additionally, I learned that the factorial of 23 (23!) equals 25,852,016,738,884,976,640,000, which interestingly has 23 digits, a unique coincidence among factorials. I found out that medical specialists often spend less than 10 minutes with patients, and that watching TV can contribute to weight gain. Other insights included the fact that a kiss can transfer around 80 million microbes, and that bureaucracy can sometimes hinder employment opportunities. The discussion also touched on various trivia, such as the emotional sensitivity of barn owls and the complexities of gravitational lensing around black holes.
Physics news on Phys.org
1oldman2
- 1,450
- 1,210
TIL, That all this time I thought my dog was named after a moon of Uranus (Oberon), today I saw the spelling is Oberyn and the name comes from Game of thrones. 
Pepper Mint
- 91
- 139
Today I learned

He is the king of fairies!1oldman2 said:TIL, That all this time I thought my dog was named after a moon of Uranus (Oberon), today I saw the spelling is Oberyn and the name comes from Game of thrones.![]()

1oldman2
- 1,450
- 1,210
Oh no! His other designation is Uranus IV, a china company a brewery etc. etc. according to Wiki, I'm laughing in my mind.Pepper Mint said:
Last edited:
jim hardy
Science Advisor
Homework Helper
Dearly Missed
- 9,832
- 4,898
I hope this helps somebody
Today i learned why there are so many laptop power receptacles for sale on Ebay.
Mine got to where i had to hold it to make contact. Then it quit altogether .
I might've mentioned that earlier... i promised pictures.
First fix only lasted a couple weeks.
It cracked right behind the connector
here's the connector
here's where it cracked
how the small things of the Earth confound the mighty, eh ?...
Okay, first time i just soldered over the crack.
and
had to reassemble it multiple times because i kept forgetting to hook up cables or leaving out parts
and two of the little black retainer clamps that hold the flat cables into their connectors crumbled away
this one killed my sound and usb ports
other one disabled the power switch but a matchstick held it sort of in place
After a couple weeks the power connector cracked again
so That day I Relearned "You can't use solder to replace mechanical strength"...
So i took it all apart again
pulled that rear piece out , the L shaped one (that cracked ) at rear of power connector going down to the board,
... replaced it with a piece of flexible #24 wire
sorry, i didnt get an "after" picture
I wrapped the teeny wire around that short stub at connector backside, where the crack is, and soldered it in place there and down on the board leaving a stress relief loop in it.. Now if it needs to flex it can do so. It only has to handle 3 amps which #24 can do .
@Planobilly i sure need better soldering equipment for this newfangled stuff. It's Hideously tiny.
Put it back together again - and lost another little black connector. retainer/clamp. Screen wouldn't work.
Rats ! This is getting old !
off to computer shop to see if he has a junkpile with boards to scrounge little black connector retainer thingies, no luck.
Let it sit two days while i resist the urge to "Terminate" ...
Okay one last try
i looked for plastic about the right thickness to jam into those connectors to hold the flat cables down in lieu pf proper retainers .
Aha ! trial and error ... uswag too...
the top from a cottage cheese container is nice polyethylene and proved a snug fit.
With magnifier glasses and scissors i cut pieces to size and was able to work them in under the pins with needle nose pliers.
Flat cables are nice and tight now without matchsticks(which didnt work well anyway) .
.At last, tonight, old laptop is going again . It ran four years prior without hardware trouble, touchpad shows the miles.. It owes me nothing .
...here it is all back together except keyboard .
Tools point to connector in previous picture.
.
Whew !
i made this post with it -Sorry if i bored you. Hope it helps somebody.
old jim
Today i learned why there are so many laptop power receptacles for sale on Ebay.
Mine got to where i had to hold it to make contact. Then it quit altogether .
I might've mentioned that earlier... i promised pictures.
First fix only lasted a couple weeks.
It cracked right behind the connector
here's the connector
here's where it cracked
how the small things of the Earth confound the mighty, eh ?...
Okay, first time i just soldered over the crack.
and
had to reassemble it multiple times because i kept forgetting to hook up cables or leaving out parts
and two of the little black retainer clamps that hold the flat cables into their connectors crumbled away
this one killed my sound and usb ports
other one disabled the power switch but a matchstick held it sort of in place
After a couple weeks the power connector cracked again
so That day I Relearned "You can't use solder to replace mechanical strength"...
So i took it all apart again
pulled that rear piece out , the L shaped one (that cracked ) at rear of power connector going down to the board,
... replaced it with a piece of flexible #24 wire
sorry, i didnt get an "after" picture
I wrapped the teeny wire around that short stub at connector backside, where the crack is, and soldered it in place there and down on the board leaving a stress relief loop in it.. Now if it needs to flex it can do so. It only has to handle 3 amps which #24 can do .
@Planobilly i sure need better soldering equipment for this newfangled stuff. It's Hideously tiny.
Put it back together again - and lost another little black connector. retainer/clamp. Screen wouldn't work.
Rats ! This is getting old !
off to computer shop to see if he has a junkpile with boards to scrounge little black connector retainer thingies, no luck.
Let it sit two days while i resist the urge to "Terminate" ...
Okay one last try
i looked for plastic about the right thickness to jam into those connectors to hold the flat cables down in lieu pf proper retainers .
Aha ! trial and error ... uswag too...
the top from a cottage cheese container is nice polyethylene and proved a snug fit.
With magnifier glasses and scissors i cut pieces to size and was able to work them in under the pins with needle nose pliers.
Flat cables are nice and tight now without matchsticks(which didnt work well anyway) .
...here it is all back together except keyboard .
Tools point to connector in previous picture.
.
Whew !
i made this post with it -Sorry if i bored you. Hope it helps somebody.
old jim
Last edited:
Planobilly
- 440
- 105
About Jim's laptop repair...
It is pretty inspiring than anyone would even attempt to repair a laptop in the first place. It is obvious that consumer computer devices are not designed to be long lasting or designed to be repaired. I have a hard time even speaking in a polite manner about such 'Hideously tiny" contraptions..lol
At first glance, one would think, a repair of this nature would fall into the realm of"electronics repair". The truth is that, it is more complex than just re-flowing a solder joint as Jim discovered in finding a solution to the issue. This is a "moving part" and the electrical chord can put all kinds of stresses on the removable connection device and it's connection to the PCB.
I assume there was little attention given to the mechanical characteristics of the connector during the design of the laptop. I have little doubt the the concept of "modulus of elasticity or resilience" ever came up even in passing conversation as it pertains to this component...lol
Repairing anything in today's world is a concept that is rapidly fading into ideas and methods of a distance past. We are increasingly living in a disposable world and "drowning on dry land" in a sea of junk.
Cheers,
Billy
It is pretty inspiring than anyone would even attempt to repair a laptop in the first place. It is obvious that consumer computer devices are not designed to be long lasting or designed to be repaired. I have a hard time even speaking in a polite manner about such 'Hideously tiny" contraptions..lol
At first glance, one would think, a repair of this nature would fall into the realm of"electronics repair". The truth is that, it is more complex than just re-flowing a solder joint as Jim discovered in finding a solution to the issue. This is a "moving part" and the electrical chord can put all kinds of stresses on the removable connection device and it's connection to the PCB.
I assume there was little attention given to the mechanical characteristics of the connector during the design of the laptop. I have little doubt the the concept of "modulus of elasticity or resilience" ever came up even in passing conversation as it pertains to this component...lol
Repairing anything in today's world is a concept that is rapidly fading into ideas and methods of a distance past. We are increasingly living in a disposable world and "drowning on dry land" in a sea of junk.
Cheers,
Billy
mfb
Mentor
- 37,391
- 14,222
That reminds me of this story.
Expected "repair" costs: $4500 to replace the battery pack in a hybrid car.
Actual repair costs at home: $10 for chemicals and a few hours of work
Needs experience with high voltage, however, and certainly kills any warranty for any parts.
Expected "repair" costs: $4500 to replace the battery pack in a hybrid car.
Actual repair costs at home: $10 for chemicals and a few hours of work
Needs experience with high voltage, however, and certainly kills any warranty for any parts.
dlgoff
Science Advisor
Gold Member
- 4,441
- 3,276
Hopefully this isn't you cleaning the magnets buss bars.mfb said:That reminds me of this story.
Expected "repair" costs: $4500 to replace the battery pack in a hybrid car.
Actual repair costs at home: $10 for chemicals and a few hours of work
Needs experience with high voltage, however, and certainly kills any warranty for any parts.

image compliments of http://www.supraconductivite.fr/en/index.php?p=applications-accelerateurs
ProfuselyQuarky
Gold Member
- 857
- 588
Today I learned how to hold a barre chord! 

Pepper Mint
- 91
- 139
TIL a monthly income for a cleaner in the US is around $1600.
1oldman2
- 1,450
- 1,210
TIL, That in December of 1944 the US army dispatched OSS agent (and former baseball star) Moe Burg to Switzerland to assassinate W. Heisenberg. After a period of time the hit was called off due to lack of opportunity, W. H. was much more fortunate than many physicists in Stalin's purges, makes me wonder how many in science have died over politics...
zoobyshoe
- 6,506
- 1,268
I take it they were afraid Heisenberg was working on a bomb?1oldman2 said:TIL, That in December of 1944 the US army dispatched OSS agent (and former baseball star) Moe Burg to Switzerland to assassinate W. Heisenberg. After a period of time the hit was called off due to lack of opportunity, W. H. was much more fortunate than many physicists in Stalin's purges, makes me wonder how many in science have died over politics...
1oldman2
- 1,450
- 1,210
Exactly, I came across this while reading "American Prometheus" a great bio of J. R. Oppenheimer. I highly recommend the book.zoobyshoe said:I take it they were afraid Heisenberg was working on a bomb?
Stephanus
- 1,316
- 104
Are you certain?1oldman2 said:TIL, That in December of 1944 the US army dispatched OSS agent (and former baseball star) Moe Burg to Switzerland to assassinate W. Heisenberg. After a period of time the hit was called off due to lack of opportunity, W. H. was much more fortunate than many physicists in Stalin's purges, makes me wonder how many in science have died over politics...
1oldman2
- 1,450
- 1,210
Since this deals with Heisenberg there is an uncertainty principal involved.Stephanus said:Are you certain?
jim hardy
Science Advisor
Homework Helper
Dearly Missed
- 9,832
- 4,898
i think there was an episode about that in the series "Heavy Water Wars", which we stumbled across on Netflix.zoobyshoe said:I take it they were afraid Heisenberg was working on a bomb?
OCR
- 994
- 934
It certainly looks that way...Stephanus said:Are you certain?
Wikipedia® said:From 24 January to 4 February 1944, Heisenberg traveled to occupied Copenhagen, after the German army confiscated Bohr's Institute of Theoretical Physics. He made a short return trip in April. In December, Heisenberg lectured in neutral Switzerland. The United States Office of Strategic Services sent former major league baseball catcher and OSS agent Moe Berg to attend the lecture carrying a pistol, with orders to shoot Heisenberg if his lecture indicated that Germany was close to completing an atomic bomb.
Last edited:
Stephanus
- 1,316
- 104
Today I learned, actually yesterday, that...
for multi cores processor there are as many as register set as the cores.
So for a computer with four cores there are 4 AX, 4 BX, 4 CX set.
And for hyperthreading cores, there are twice number of register set as opposed to non hyperthreading.
Thank you very much PF Forum.
for multi cores processor there are as many as register set as the cores.
So for a computer with four cores there are 4 AX, 4 BX, 4 CX set.
And for hyperthreading cores, there are twice number of register set as opposed to non hyperthreading.
Thank you very much PF Forum.
OCR
- 994
- 934
Stephanus said:Are you certain?
Oh my.....

That was a joke, wasn't it ? ...

And it certainly was not an observable by me.....
...
Last edited:
CynicusRex
Gold Member
- 98
- 68
Smartphone GPS does not work on the ISS.
"Commercial GPS equipment is hardcoded to not work at great altitude or at great speed to prevent GPS being used to guide weapons." –Robert Frost
"Commercial GPS equipment is hardcoded to not work at great altitude or at great speed to prevent GPS being used to guide weapons." –Robert Frost
Borg
Science Advisor
Gold Member
- 2,293
- 5,005
Seems like overkill unless the U.S. thinks that North Korea is using iPhones to guide their missles.TheBlackAdder said:Smartphone GPS does not work on the ISS.
"Commercial GPS equipment is hardcoded to not work at great altitude or at great speed to prevent GPS being used to guide weapons." –Robert Frost

mfb
Mentor
- 37,391
- 14,222
Using commercial devices would certainly be more convenient than writing the software on your own. But yeah, if you can make a nuclear weapon and an intercontinental missile you can probably write code to determine your location and speed based on GPS signals.Borg said:Seems like overkill unless the U.S. thinks that North Korea is using iPhones to guide their missles.![]()
Ibix
Science Advisor
- 13,430
- 15,979
But at least they won't have sleek, stylish nukes...Borg said:Seems like overkill unless the U.S. thinks that North Korea is using iPhones to guide their missles.![]()
1oldman2
- 1,450
- 1,210
Their "PR" department is hard at work on that problem.Ibix said:But at least they won't have sleek, stylish nukes...
1oldman2
- 1,450
- 1,210
TIL, while browsing http://isslive.com/operations.html I learned that I have the training to perform at least one aspect of "contingency maintenance" aboard the ISS
(This is a useful site for space geeks)
(This is a useful site for space geeks)
mfb
Mentor
- 37,391
- 14,222
But can you bang with a hammer transferring an impulse of 0.6 kg m/s within 10% tolerance?
OmCheeto
Gold Member
- 2,483
- 3,409
1oldman2 said:TIL, while browsing http://isslive.com/operations.html I learned that I have the training to perform at least one aspect of "contingency maintenance" aboard the ISS(This is a useful site for space geeks)
...
First, we have to define; "hammer".
OmCheeto said:...
I told him to stop, turn off his lights, and give me his lug wrench.
He was somewhat perplexed, as changing his tire didn't seem to be the right option for fixing a "starter" problem.
Anyways, I rapped the top of both of his battery connectors, and said "try now".
The car started.
Just got back from a minor vacation, where my friends and I stayed in an AirBnB.
At one point, I broke the closet door in the hallway. "It won't close!"
One of my friends said; "Just kick it!"
So I did, and it fixed the problem.
TIL, that, IMHO, hammers, in all their incarnations, are most awesome tools.
Pepper Mint
- 91
- 139
Greg, TIL a Mexican of C++ gave your PF mobile product only 3 stars 

Stephanus
- 1,316
- 104
Borg said:Seems like overkill unless the U.S. thinks that North Korea is using iPhones to guide their missles.![]()
@mfb beats me. That's what I'm going to say. I concur.mfb said:Using commercial devices would certainly be more convenient than writing the software on your own. But yeah, if you can make a nuclear weapon and an intercontinental missile you can probably write code to determine your location and speed based on GPS signals.
Stephanus
- 1,316
- 104
Hammers? But I think ISS is mostly United States', (although the "I" stands for International) not Russian's.1oldman2 said:TIL, while browsing http://isslive.com/operations.html I learned that I have the training to perform at least one aspect of "contingency maintenance" aboard the ISS(This is a useful site for space geeks)
View attachment 103162
I can't help but remember a scene in Armageddon Movie.
There's a malfunction in "Freedom" shuttle ship. And here's the dialog between two astronouts.
American: Don't touch that you don't know American components.
Russian: American components, Russian components all made in Taiwan!
And the Russian produces a hammer, bangs it twice and voila! It starts.
Similar threads
- · Replies 14 ·
- Replies
- 14
- Views
- 2K
- Replies
- 26
- Views
- 6K
- · Replies 11 ·
- Replies
- 11
- Views
- 4K
- · Replies 161 ·
- Replies
- 161
- Views
- 14K
- · Replies 4 ·
- Replies
- 4
- Views
- 2K
- · Replies 9 ·
- Replies
- 9
- Views
- 2K
- Replies
- 35
- Views
- 7K
- · Replies 3 ·
- Replies
- 3
- Views
- 3K
- · Replies 2 ·
- Replies
- 2
- Views
- 349
- · Replies 27 ·
- Replies
- 27
- Views
- 6K