Today I Learned

  • Thread starter Thread starter Greg Bernhardt
  • Start date 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.
  • #241
James Prescott Joule, born 24 December 1818, along with being a physicist, was also, a brewer.

hmmm... that might explain some things...
 
Physics news on Phys.org
  • #242
TheDemx27 said:
Today I learned a lot of important things pertaining to vectors. I also learned that the symbol representing the vector differential operator is called "nabla".
Yup. More commonly called the "del" operator, it is represented using the nabla symbol. (It looks like an upside down, capital "delta" symbol.)

It is represented in \LaTeX using
Code:
\nabla
so you can write cool things like
<br /> \nabla f = \frac{\partial f}{\partial x} \hat x + \frac{\partial f}{\partial y} \hat y + \frac{\partial f}{\partial z} \hat z<br />

It's also used in different, yet related ways to represent the divergence \left( \nabla \cdot \vec v \right), curl \left( \nabla \times \vec v \right) and Laplacian \left( \nabla \cdot \nabla = \nabla^2 \right).
 
Last edited:
  • Like
Likes Medicol and TheDemx27
  • #243
Today I learned, or more accurately realized, that "cosmic" and "comic" are only one letter away.
 
  • #244
collinsmark said:
It's also used in different, yet related ways to represent the divergence \left( \nabla \cdot \vec v \right), curl \left( \nabla \times \vec v \right) and Laplacian \left( \nabla \cdot \nabla = \nabla^2 \right).

Today I learned what I want to learn next. :biggrin:
 
  • #245
Today I learned that sheep can dig snow holes! I was out walking in Scotland when suddenly a sheep fought its way out of a bank of snow about 20m away. Then three more followed it. As far as I could tell they had completely buried themselves. Probably to stay warm. Extraordinary!
 
  • #246
Today I learned that the University of Chicago police will approach you in the bathroom and ask for identification after you've been in a car for 4 hours and really need to use the facilities. As a bonus, I learned why my daughter will be attending graduate school in Westwood.
 
  • #247
Today I learned that if I randomly pick 100 men in the US, the probability that I can get 3 - 5 of them as gay or bisexual is about 95%-99%. Is this a normal distribution ?:nb)
I'm glad to see people prefer living the life they like to leading the one unwillingly! :)
 
  • #248
Today I learned that Laplace's http://Méchanique Céleste (1799 - 1825) was used by Sir Isaac Newton.

I learned this from p.240 of "Differential Equations for Dummies" by Steven Holzner, which surely was also used by Sir Isaac Newton.
 
Last edited by a moderator:
  • Like
Likes zoobyshoe, Medicol and OmCheeto
  • #249
Today I learned that crows winter with their parents then help to build the nest and raise their siblings in the spring.
 
  • #250
Yesterday I learned I was probably coming down with flu, despite my flu shot.

Today I learned I'm probably not coming down with the flu.
 
  • Like
Likes davenn and Medicol
  • #251
lisab said:
Yesterday I learned I was probably coming down with flu, despite my flu shot.

Today I learned I'm probably not coming down with the flu.

Had a similar experience minus the flu shot, a semi-good night of sleep sure helps.
 
  • #252
Just found out that photons have a "shape".

This really throws a monkey wrench into my bestest, and unfortunately, the last of my crackpot theories.

I guess, it's time, to wash the dishes.
 
  • #253
Today I learned that euler's identity is abbreviated cis(x). Now I can make some offensive math joke with ties to trans/cis people.
 
  • #254
Today I learned the first microwave oven was made in 1947.
 
  • #255
Today I learned that the quotient group Z / (i - 2) is isomorphic to Z / 5Z. Pretty neat, eh?
 
  • #256
This is the molecule for propane. I got it wrong at trivia tonight :(
Propane-Atom.gif
 
  • #257
I learned some frogs like tropical islands
 
  • Like
Likes Greg Bernhardt
  • #258
I learned that iron atoms flouresce under illumination with copper K-##\alpha## radiation.
 
  • #259
Greg Bernhardt said:
This is the molecule for propane. I got it wrong at trivia tonight :(
Propane-Atom.gif

I hope you don't expect me to like that post.
 
  • #260
Borek said:
I hope you don't expect me to like that post.
I was wishing I could "phone a friend" :D
 
  • Like
Likes dlgoff, Borg and Borek
  • #261
Today I learned that I really should start listening to my parents as they genuinely do know best.
 
  • #262
Today I learned there's a Ford F series truck sold every 43 seconds.
 
  • #263
iDimension said:
Today I learned that I really should start listening to my parents as they genuinely do know best.
once you realize this, you no longer need to heed their advice. It's weird, I know.
 
  • #264
iDimension said:
Today I learned that I really should start listening to my parents as they genuinely do know best.

This lesson is a classical part of a process called "maturing".
 
  • #265
Borek said:
This lesson is a classical part of a process called "maturing".

Another version of maturing is that you realize your parents are uneducated bigots and that you don't need their blessing.
 
  • #266
Pythagorean said:
Another version of maturing is that you realize your parents are uneducated bigots and that you don't need their blessing.
iDimension said:
Today I learned that I really should start listening to my parents as they genuinely do know best.
It's most likely going to be somewhere in between the two extremes: blinding accepting everything they say, and completely rejecting everything that comes out of their mouths. I bet where you fall on the spectrum between these two situations depend on: How smart your parents are and how you were raised when you were young.
 
  • #267
TheDemx27 said:
How smart your parents are

and how smart you are.
 
  • #268
Borek said:
and how smart you are
The way I see it, the two possible things you can base your intelligence on is heredity and the environment you were raised in at an early age; both are provided by your parents. Of course after you come of some age you start acting for yourself, but the largest influence by far comes from the very early years.
 
  • #269
TheDemx27 said:
The way I see it, the two possible things you can base your intelligence on is heredity and the environment you were raised in at an early age; both are provided by your parents. Of course after you come of some age you start acting for yourself, but the largest influence by far comes from the very early years.

There's actually something called a 50-0-50 rule in psychology that pertains to personality and intelligence. It states that intelligence and personality are 50% genetics, 0% correlated with raising, and 50% with peers. They found this by comparing monozygotic twins raised by their biological parents to twins raised by adopted parents. And, obviously, its's a rough approximation. I believe some studies find a higher balance towards genetics with intelligence (like 64-0-35 or something).
 
  • #270
Today I learned there is something called a 50-0-50 rule in psychology that pertains to personality and intelligence.
 

Similar threads

  • · Replies 14 ·
Replies
14
Views
2K
Replies
26
Views
6K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 161 ·
6
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
339
  • · Replies 27 ·
Replies
27
Views
6K