• Quick note - the problem with Youtube videos not embedding on the forum appears to have been fixed, thanks to ZiprHead. If you do still see problems let me know.

A scientific fact/tidbit you recently learned that you thought was interesting

Ryan O'Dine said:
I'm prolly misunderstanding... something... but I believe a mirror flips across the depth axis (z, not x or y).
Click to expand...
Yes, a mirror flips front to back, not left and right.

If I'm looking south, my image in the mirror is looking north. If I raise my east arm, my image also raises its east arm.

The phenomenon is illustrated by Sandi in this episode of QI (don't worry, it's not the whole episode):

 
arthwollipot said:
Yes, a mirror flips front to back, not left and right.

If I'm looking south, my image in the mirror is looking north. If I raise my east arm, my image also raises its east arm.

The phenomenon is illustrated by Sandi in this episode of QI (don't worry, it's not the whole episode):

Click to expand...

Touch the mirror. Why would your hand's reflection be anywhere except where it is?
 
a_unique_person said:
A mirror flips across the vertical axis. A camera lense flips across the horizontal axis.
Click to expand...
As everyone else is dogpiling on, I'll add:
The mirror doesn't flip left and right, the human flips left and right in their mind as they translate their own shape onto the shape of their reflection. When you raise your left hand your reflection does not raise its right hand. You might think it does because you mentally revolve the image on a vertical axis due to humans' symmetry. But the reflection has flipped front to back, not left to right, and that's harder to imagine.

The lens also makes an image that's flipped front to back but also inverted, which is effectively rotated 180°, rather than one that's just flipped top to bottom.
 
Jack by the hedge said:
The mirror doesn't flip left and right, the human flips left and right in their mind as they translate their own shape onto the shape of their reflection. When you raise your left hand your reflection does not raise its right hand. You might think it does because you mentally revolve the image on a vertical axis due to humans' symmetry. But the reflection has flipped front to back, not left to right, and that's harder to imagine.
Click to expand...
That's why I like describing it using cardinal directions. It's a framing that works for me.
 
Jack by the hedge said:
As everyone else is dogpiling on, I'll add:
The mirror doesn't flip left and right, the human flips left and right in their mind as they translate their own shape onto the shape of their reflection. When you raise your left hand your reflection does not raise its right hand. You might think it does because you mentally revolve the image on a vertical axis due to humans' symmetry. But the reflection has flipped front to back, not left to right, and that's harder to imagine.

The lens also makes an image that's flipped front to back but also inverted, which is effectively rotated 180°, rather than one that's just flipped top to bottom.
Click to expand...

I'm never quite sure where the line is where I'm supposed to switch from "what they would regard as their right hand" to "the hand that's on the same side as my right hand" if you get my drift.
So things like mannequins, robots/android, hominid depictions, decomposing skeletons etc. Where's the line where "objectification" becomes appropriate?
 
I don't think there's a line, just a context if you're lucky. Which is why "stage left" is such a useful concept, for removing the ambiguity.
 
Jack by the hedge said:
I don't think there's a line, just a context if you're lucky. Which is why "stage left" is such a useful concept, for removing the ambiguity.
Click to expand...

It would be so much simpler if all the world were a stage, and all the men and women merely players.
 
We often think of the wheel as the first invention, but turns out it's not even close...with earliest known appearances around 5500 BC, it's outdone by:

Cooking // 1.8 Million–500,000 BC
Glue // 200,000 BC
Clothing // 150,000 BC
Jewelry // 110,000 BC
Boats // 43,000–8000 BC
Musical Instruments // 41,000 BC
Geographic Maps // 12,000 BC
Pottery // 18,000 BC
Calendars // 8000 BC
Alcohol // 7000 BC
Bow and Arrow // 7000 BC
 
bigred said:
We often think of the wheel as the first invention, but turns out it's not even close...with earliest known appearances around 5500 BC, it's outdone by:

Cooking // 1.8 Million–500,000 BC
Glue // 200,000 BC
Clothing // 150,000 BC
Jewelry // 110,000 BCBoats // 43,000–8000 BC
Musical Instruments // 41,000 BC
Geographic Maps // 12,000 BC
Pottery // 18,000 BC
Calendars // 8000 BCAlcohol // 7000 BC
Bow and Arrow // 7000 BC
Click to expand...

That's 102,000 years of having to sleep on the sofa due to not having any help in remembering to get jewelry for the wedding anniversary. I'm surprised that humanity survived!
 
Here_to_learn said:
That's 102,000 years of having to sleep on the sofa due to not having any help in remembering to get jewelry for the wedding anniversary. I'm surprised that humanity survived!
Click to expand...
Note that alcohol and calendars were relatively in a comparable era :)
 
Actually, when it comes to invention, a case can be made (as it has been) for compound tools. Specifically, although we have abundant evidence of other animals using tools, a stick to poke, a rock to smash, etc., what distinguishes human beings from other animals is the decision to put two disparate things together to form a more effective tool. Two sticks jointed, a lever to push a spear, a handle on a rock, etc. It is at this point that a thing can be considered invented.
 
This is pretty easy to figure out but it hadn't occurred to me before.

A fully pressurized commercial non-cryogenic oxygen tank (at about 150 atmospheres pressure) would contain more than four times as much oxygen if it were filled with water instead.
 
Myriad said:
This is pretty easy to figure out but it hadn't occurred to me before.

A fully pressurized commercial non-cryogenic oxygen tank (at about 150 atmospheres pressure) would contain more than four times as much oxygen if it were filled with water instead.
Click to expand...

"Water water everywhere, and not a drop to breathe" he thought, drowning.
 
rjh01 said:
There is an axis of evil in the cosmic microwave background and that is its real name. It should not exist but it cannot be explained away. Watch this video by Dr. Becky to find out more

httpx://www.youtube.com/watch?v=SDRNvhbrz3k

I've REALLY soured on Dr. Becky! I HATE ads, and she's now putting them right into her bloody videos. I will not be viewing anything she puts online from here on in. Screw that obnoxious crap.
Click to expand...
 
Last edited:
Blue Mountain said:
rjh01 said:
There is an axis of evil in the cosmic microwave background and that is its real name. It should not exist but it cannot be explained away. Watch this video by Dr. Becky to find out more

httpx://www.youtube.com/watch?v=SDRNvhbrz3k

I've REALLY soured on Dr. Becky! I HATE ads, and she's now putting them right into her bloody videos. I will not be viewing anything she puts online from here on in. Screw that obnoxious crap.
Click to expand...

You will find so many channels do the same thing.
Click to expand...
 
You must log in or register to reply here.

Back
Top Bottom