Tropical cyclone, Earth, North Pole Hurricane Coriolis Effect Demonstration Machine
It was off the coast of the carolinas uh in september 2019, as you can see, it’s rotating counterclockwise. This is the equator. This was a hurricane katarina, sometimes called cyclones when they’re below the equator. If you look, this was rotating clockwise since it formed below the equator. Now, the reason that happens is based on something called the coriolis effect sometimes referred to as just correlative force, but they’re really related, so which basically i’m going to read a little statement here. I got off the internet that a coriolis effect is an effect whereby a mass moving and a rotating system experiences a force, namely the coriolis force, acting perpendicular to the direction of motion to axis of rotation on the earth. The effect tends to deflect moving objects to the right in the northern hemisphere and to the left in the southern hemisphere, and this is important in large psychonic storms like hurricanes tropical cyclones when they form above the equator. They always rotate counterclockwise and below clockwise tornadoes. On the other hand, the normal rotational direction above the equator is counterclockwise. They call that cyclonic, but they can’t occasionally rotate clockwise or antipsychotic, and the reason is they’re much smaller. They don’t have as much of the coriolis effect as the really large tropical cyclones do so. I’M going to remove these when you just look a little bit better, but imagine the earth rotating in this direction like this towards the east um, the surface of the earth, normal surface velocities roughly a thousand miles an hour and as you can see, if you go Right up to the say, in this case north poles, conversely the south pole, but for any amount of distance of movement here so many degrees of movement.
This surface moves a long distance and this is barely moving anywhere when you’re right at the axis of rotation. So the surface velocity here is high. It progressively gets lower as you go this way. Big psychotic storms like dorian, have a low pressure in the center air is trying to rush in air and water vapor, of course, from all directions into that low. The air is rotating along with the earth out. Here is moving at a certain velocity, as it goes say this way up into the northern hemisphere it’s hitting an area of the earth that’s, not rotating as fast, so it tends to overrun it and go off to the right. Same thing is true of the air. Coming in this direction only backwards, it’s rotating the air, mass and water vapor mass – is relatively slow, moving into a faster moving area, so it tends to make it go to the right that way and that’s what makes it a counterclockwise rotation same thing is true down Here in the southern hemisphere, only obviously the other direction, so what i wondered is: can i make a mechanical analog of the earth with a mechanical analog of a cyclone and demonstrate that effect, basically mechanically, so that’s what we’re going to try to do? Okay? This is my mechanical storm. Analog i’ve got spinner here, spins freely lead weights to simulate air mass water, vapor mass rushing towards a center central low. This is, it was very difficult to try and do this with a spherical type of earth, because in the planet, earth center of gravity is is earth and this device gravity is pulling straight down.
So what i decide to do is just approximate the worst case situation, which would be um if we can’t demonstrate this with the weights just moving straight towards axis pretending. This is the northern hemisphere of the earth and underneath is the southern hemisphere – i’m, not a flat. Earther, so don’t don’t get that idea, but uh. If you look underneath here, i’ve got some twine running around this central spool here, so when this spins it tightens up okay, if you look carefully the strings at the bottom of this, under what we showed you underneath are tied to loops of nylon twine it’s number 18 nylon, i believe these loops go through the screw eyes on these lead weights loop around and come over to these paper clips that i’ve modified and glued to the side here. So if you look closely i’m going to just pull those down through and you’ll, see how they release the lead weights watch see how the weights are moving towards the center as they approach the center. The string comes off those paper clips and the less weights are released that’s so that this thing can move freely even after the weights have been all the way pulled to the center what’s interesting. If you look at the uh, if this is turning counterclockwise here say the northern hemisphere, if you would actually look up underneath what looks counterclockwise, this is looking clockwise from underneath, where storms, spin clockwise in the southern hemisphere and counterclockwise in the northern but uh i’m, going To show you another interesting effect here, let me put this on the tripod.
Okay, you watch our spinner here. Let’S put these weights back out the edges. If normal earth rotation would be rotating towards the east, okay we’ve got this set up. We can rotate it in either direction. That would be normal, but you’ll notice when this accelerates this tends to move in a clockwise direction. If we accelerate like the earth rotating towards the east, the other direction, it goes the other way. Okay, it only does that on acceleration. If i just move this very slowly and come up to a uniform speed, it doesn’t do that now that created some interesting complications. Trying to make this simulation device, the other interest thing you’ll notice – that if i just move this device like this, it doesn’t do that it’s. Only when it’s rotating it doesn’t do that. Okay, we’re, going to rotate our device towards the east there’s no strings here. So the weights will stay put on the outer edges and you’ll notice. It will appear to rotate clockwise when this device accelerates going around this axis, some of that’s, probably newton’s first law of motion that everything wants to stay at rest unless there’s a force on it. Because it can swivel around this bearing here, but it does appear at least be rotating clockwise. I think some of that’s just uh inertia but you’ll, see it’ll continue to do that and it’ll reach a point until it stabilizes and you don’t see that apparent rotation anymore and then it will just stay there.
Okay, because these weights are stable, they’re, not going in towards the center okay. If you watch this spinner here as i rotate this whole device towards the east blood weights, stay pretty constant. There are strings attached, but the string is still taking up the slack, and this thing is rotating clockwise it’ll reach a point where it’ll just stop rotating and then the strings will tighten up and it’ll move in the opposite direction. Okay, it’s stopped. My strings will tighten up, the weights will start coming in and you’ll see it start to rotate counterclockwise, because the weights are putting a force on this little device here. So there it goes. It’S rotating counterclockwise that’s. What you’d expect with a storm in the northern hemisphere? Okay, okay, we’re going to rotate this device towards the west, and this will be without strings. So when you watch it turn, you notice the weights here or it’ll. Be stationary we’ll, give it a spin towards the west. Of course, the earth doesn’t normally rotate that direction, but this is just for demonstration notice how this is going counterclockwise, the acceleration effects it will stabilize and it in this case there are no strings, so the weights won’t come in, so it should just stabilize and eventually Just stay put really to this: this uh, basically the clock numbers i’ve got here, see it’s pretty much stabilized now pretty much that’s the point in between two and three and not moving all right this towards the west.
Now we have strings attached notice, it’s rotating counterclockwise it’ll reach a point where it’ll stop rotating because strings are attached there, they go they’re pulling the weights in let’s, see that coriolis force. These lead weights start to push this thing this one this way and that one that way and make it rotate clockwise. In fact, you can see it see how it’s close over there and close on that side. I hope you enjoyed this video if you did. Please click on the subscribe button and check out our other videos. Thank you very much and please like us.