Dirty Jobs: These guys never made any sawdust...

[Dan Mitchell]

Had to post this. I was just watching the intro of an episode of the program "Dirty Jobs" on Discovery Channel. Part of the intro shows a circular saw blade traversing some wood from left to right, rotating clockwise. Below is a screen shot. The blade is rotating BACKWARDS from the direction of the teeth!

Should we tell 'em?

[Chris S Anderson]

Maybe its filmed or edited in Autstralia...the toilets flush backwards there, too.

[Pat Germain]

Maybe its filmed or edited in Autstralia...the toilets flush backwards there, too.

Interesting. That's the second time today I've read that reference. What makes it even more interesting is many people believe it's true. :p

[Jason Roehl]

Pat, I lived in Brazil for a year. Our toilets all flushed the opposite way of what they do here in the U.S.!

[Mitchell Andrus]

The blade is clearly marked "Made in Japan". What do you expect?

.....and, I'm guessing the blade guard has been removed for demonstration purposes. Right!
.

[Bill Arnold]

Maybe its filmed or edited in Autstralia...the toilets flush backwards there, too.

Check this (http://en.wikipedia.org/wiki/Flush_toilet#Swirl_direction) or this (http://www.toiletmuseum.com/faq.html#Q2) or this (http://www.discovery.com/area/skinnyon/skinnyon970523/skinny1.html).

Inquiring minds want to know! :D

[mike holden]

Jason<
"Pat, I lived in Brazil for a year. Our toilets all flushed the opposite way of what they do here in the U.S.!"
What? you lifted the handle? the handle was on the right side of the tank? The water came up from the center?

Mike

[Myk Rian]

Interesting. That's the second time today I've read that reference. What makes it even more interesting is many people believe it's true. :p
Same with bathtubs.

[Pat Germain]

Same with bathtubs.

I don't want to hijack the thread, but this is patently untrue. Coriolis affect influences hurricanes, but not drains or toilets.

Toilets are designed to force water in a particular direction. I've been south of the equator and the toilets I used swirled clockwise. But I'll accept some swirl counterclockwise because there's no way I can know how every toilet is designed.

And you don't have to believe me. :)

http://www.snopes.com/science/coriolis.asp

[Lee Schierer]

Check this (http://en.wikipedia.org/wiki/Flush_toilet#Swirl_direction) or this (http://www.toiletmuseum.com/faq.html#Q2) or this (http://www.discovery.com/area/skinnyon/skinnyon970523/skinny1.html).

Inquiring minds want to know! :D

Okay so explain why the water always twists the same way out of a sink or bath tub that doesn't have jets!

Confused minds want to know! :D

[Pat Germain]

Okay so explain why the water always twists the same way out of a sink or bath tub that doesn't have jets!

Confused minds want to know! :D

It's due to the design of the sink or tub as well as where the water is coming from. In a sink you can sometimes change the direction by filling it with the spout on the right side and draining it. Then fill it with the spout on the left side and drain it. Obviously, if you let the water sit a long time, the influence of the spout will be greatly reduced.

In a tub, it's probably more related to the shape and which way it's leaning.

[Lee Schierer]

It's due to the design of the sink or tub as well as where the water is coming from. In a sink you can sometimes change the direction by filling it with the spout on the right side and draining it. Then fill it with the spout on the left side and drain it. Obviously, if you let the water sit a long time, the influence of the spout will be greatly reduced.

In a tub, it's probably more related to the shape and which way it's leaning.

But 99 times out of 100 the water goes the same way even when water isn't being filled and has sat in the sink (tub) long enough to be still. Are all sinks (tubs) tilted the same way? Sinks with drains in the center rotate the same way as a sink with the drain near the edge. Even with tilt the water would be level and it should still have an even chance of starting rotation left instead of right, yet it never seems to. You can swirl the water counterclockwise and many times it will stop and reverse itself if the water is deep enough.

[Pat Germain]

But 99 times out of 100 the water goes the same way even when water isn't being filled and has sat in the sink (tub) long enough to be still. Are all sinks (tubs) tilted the same way? Sinks with drains in the center rotate the same way as a sink with the drain near the edge. Even with tilt the water would be level and it should still have an even chance of starting rotation left instead of right, yet it never seems to. You can swirl the water counterclockwise and many times it will stop and reverse itself if the water is deep enough.

I don't know, Lee. But I do know which side of the equator you're on has nothing to do with it.

[Jason Roehl]

I agree with you, Lee. The Snopes reference cites ONE meterology textbook. Here's the rub--no matter how the sink is shaped, whether it is level, or where the drain is located, those things only affect the water molecules that are very close to the sink boundaries--not the water molecules several inches away from the bottom of the sink.

[Keith Christopher]

Okay so explain why the water always twists the same way out of a sink or bath tub that doesn't have jets!

Confused minds want to know! :D


http://www.time.com/time/magazine/article/0,9171,834374,00.html

[Brian Kincaid]

Pat, I lived in Brazil for a year. Our toilets all flushed the opposite way of what they do here in the U.S.!

Has to do if you are above or below the equator. I guess if you live on the equator the toilet flushes side to side :D

When I was younger I tried to force the water exiting the tub to swirl the opposite way. When I stopped swirling the water opposite it would calm down and begin swirling the same way again.

-Brian

[Pat Germain]

I just got out of the shower. Having just read this thread, I observed the drain. The water was swirling counterclockwise into the drain and Colorado Springs is pretty far north of the equator.

I've been an amateur expert on urban legends for many years. I too once believed Coriolis influenced the way water swirls when it drains. I did a lot of research and discovered I was wrong.

I readily admit I'm not expert. But my research included talking to experts. I've worked with people who studied fluid flow mechanics at the US Naval Academy. It's a really bizarre and complicated field and, sometimes, it doesn't seem to make sense. For example, fluid flow mechanics has a lot to do with why an aircraft carrier is much faster than a fishing trawler. It's not just available power.

[Pat Germain]

I agree with you, Lee. The Snopes reference cites ONE meterology textbook. Here's the rub--no matter how the sink is shaped, whether it is level, or where the drain is located, those things only affect the water molecules that are very close to the sink boundaries--not the water molecules several inches away from the bottom of the sink.

Bill Arnold provided three additional sources. There's no way Coriolis is going to influence water mere inches away from a drain. With a hurricane or tropical storm, you're talking many miles.

The Time article Keith referenced is interesting. But it's from 1965 and it's not conclusive. It just reports observations from one scientist who pulled the plug and filmed the results.

[Pat Germain]

I wanted to follow up here to say I don't want to offend anyone. I have much respect for the people on SMC. I'm not suggesting anyone is stupid, ignorant, naive or lying. Nor am I saying I'm smarter than anyone else. I've just been down this road before; and it's a long road!

As I said previously, I follow urban legends. I've been doing so since I was a kid and started to figure out almost everything my classmates and teachers told me was bogus. (I even had a textbook which said blue whales were extinct.) While my intent is always to help people, sometimes they get downright mad when I inform them they're not going to get a free trip to Disney World no matter how many times they forward an email.

Years ago, one of my coworkers was insulted when I told her saving the tabs from soda cans would not buy kidney dialysis for children. I had to pick up her phone and call Reynolds Aluminum who, being familiar with this legend, politely explained it was completely bogus and they would not even recycle the tabs when detached from the cans. (Ironically, McDonald's later decided to accept the tabs and help pay for kidney dialysis.)

This issue is particularly puzzling because what we observe sure seems to confirm the legend. :)

[Keith Christopher]

The interesting thing that leads people to assume this is the way a device is filled (along with it being level and flat, imperfections on a molecular level in the sink/tub will affect this also). Even still water on the surface can have movement and stored energy below the surface. Once the drain is pulled, the energy from the draining water is passed throughout the sink. So stirring in the opposite direction will affect the surface water however the water down in the drain is -through viscosity- is affecting the water above it an so on...So once the turbulence stops up top the water and energies already in the sink and water already flowing down the drain pull things back into shape so to speak. If you stir a draining sink you will see it swirl and then suddenly it appears to 'crash' and then the initial energy takes over pulling things back down 'normally'. Think long gooey stretchy thing following a path downward pulling things with it along for the ride.