Welcome to the Science Asylum. I am Nick Lucid.
In the centrifugal force video,
we got to see how weird things look and feel when you're rotating, but the weirdness doesn't stop there.
Centrifugal force is not the only force that seems to appear when you're rotating.
There's this other one. You may have heard of it's called the Coriolis force or sometimes the Coriolis effect
That's the thing that tells you which way your toilet flushes, right?
No toilets are way too small for that. Milton roll the footage!
[Alien Noises]
I don't care if you're in the middle of something. Roll it!
These are two toilets in Michigan flushing in opposite directions.
Myth Busted!
Now, it is true that the rotation of the Earth causes a Coriolis effect.
It's just not strong enough to affect something as small as a toilet which are influenced far more by
imperfections in the toilet bowl, how level the floor is, and how the water is released from the toilet tank?
Yes
Those are monkeys on my shower curtain. Got a problem with that?
However, if we're dealing with something
really big with motion that spans over at least today. Then we'd have to worry about it.
In the Detroit science center,
they have something called a Foucault pendulum this pendulum is so big that it hangs from the top floor down to the basement floor
Since it's so big and heavy,
it's basically unaffected by all those small scale influences like the air or friction
Standing on the Earth it appears that the direction of the swing
changes throughout the day
and how much time the cycle takes depends on your latitude here at 42 degrees North it takes about?
36 hours to go all the way around
Sometimes science centers will put clocks underneath them.
Google even had one in the Google doodle on September 18, 2013.
If you're able to step off the Earth though, you'll just see the rotation of the Earth exerting a torque on the pendulum.
Bigger!
Oh yeah? Hurricanes!
Hurricanes, also called tropical cyclones, are so big you can see them from space.
In the northern hemisphere, they always rotate counterclockwise.
In the southern hemisphere, they always rotate clockwise.
In fact, it's such a major part of how hurricanes work, they can't even cross the equator.
This graphic from NASA shows the paths taken by all the hurricanes from 1985 to 2005.
Notice the gap at the equator? If you zoom in you can actually see some of them approach the equator
and veer off along it like it's a wall.
We can also make the Coriolis force more significant by returning to our friend: the merry-go-round.
Since it rotates faster than once a day we should notice the weirdness. let's say
Let's say I'm on the merry-go-round and I decide to throw a ball.
If you're watching from the ground, then the ball appears to basically travel straight once released
It's only being pulled to the ground by gravity,
which is exactly what you'd expect for something without any other forces on it.
But that's not what I see. To anyone on the merry-go-round things look really weird
See the ball veer off to one side. It looks like there's some other weird force on it
That force is the Coriolis force and it's fictitious
It's an illusion.
The Coriolis force is determined by the mass of the ball, the
rotational speed of the merry-go-round, and the motion of the ball in other words it only acts on moving
objects and only when you're taking measurements from the rotating perspective.
These things are the coolest! So much science!
So why don't we just always look from the outside and forget this whole Coriolis thing?
That's a good idea and in the centrifugal force video, I did say if at all possible
you should try to work from a perspective with no acceleration at all.
Unfortunately, sometimes that's really
inconvenient or nearly impossible. When you're trying to be practical though, sometimes
it's easier just to pretend like it's there and get through the work.
Just don't ever forget you're pretending !
So, which way does your toilet flush?
Let us know in the comments along with where you live.
Whoa, whoa, nothing specific?
Just like northern or southern hemisphere and until next time remember. It's okay to be a little crazy
you
