Name: ホイ・スティック (The Hui Stick)
Uploaded: 2021-01-14T10:28:52.000Z
Duration: 15 min 1 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

The 11th Curiosity Box is currently shipping.

I'm talking ferrofluid, a trammel of archimedes.

I can't give every item away but you will also be receiving one of these if you're

It's just a little rubbing stick and a propeller stick that has a propeller on one end and

Now when you rub the rubbing stick along the notches the propeller stick will vibrate and

the propeller will spin but the direction it spins in will obey your command.

All you have to do is say the magic word.

Well that's what we're gonna talk about today on Michael's Toys.

To see how the Hui stick works you need to come closer or I could come to you.

Now here are my hands and let's pretend that they are your hands.

When you hold the propeller stick you hold the rubbing stick across the notches in the

other but you don't just rub the rubbing stick across the notches like this.

The trick is that you hold the stick like this so that when it's engaged with the

notches you can press against the propeller stick from one side with your index finger

So as you rub across the notches you are also dragging a finger and constantly pressing

a finger against one side of the stick or the other.

I'll try to make them far apart so it's very obvious when I switch.

I 'm constantly pressing against the stick from the right with my thumb and now here

We've got some rotation and that is in a counterclockwise direction but now I'm going

to switch so that my finger, my index finger, presses against the left side of the propeller

Well to begin this investigation let's talk about how the propeller stick moves when the

Well that should cause up and down motion.

No matter how hard you try, there will always be a little bit of error.

Even if it's just the width of an atom, horizontally and that's really all it takes

for a little bit of rotation to be induced.

Take something like a pencil and a roll of tape or some other ring-shaped object.

Put the pencil through and try to move the pencil only up and down.

No matter how hard you try, rotation will always result.

Only if you're able to move the pencil up and down right through the exact center of

mass of the ring so you only push it up and down will you not get rotation but the tiniest

little error from there introduces a torque which causes rotation and then a feedback

This is exactly what's happening with the hui stick.

I don't know if you can tell but the shaft that connects the actual propeller blades

to the propeller stick is much thinner than the propeller hole.

Here's an example that's been deconstructed.

You see that shaft there's quite thin and the hole in the propeller's pretty big.

This means that as that shaft bounces around it really does bounce around inside the propeller's

hole and can push and drag through friction the propeller around.

To see how exactly those vibrations of the propeller stick work we got some great slow

I took a laser measure that shoots out a laser beam, there's the dot, and I gripped this

in the same hand as the hui stick and projected the laser point on a wall across the room

so that when I stroked the notches they would both, the laser measure and the hui stick,

they would both vibrate together and I could look at how it vibrated.

Now when I don't even press a finger against the propeller stick I still get pretty chaotic

The propeller stick doesn't just vibrate straight up and down.

It does move in circles sometimes but it's quite a mess.

But if I press my index finger against the left side the laser pointer moves clockwise.

And if I press my thumb against the right side the laser pointer rotates counterclockwise.

And because the shaft has room inside that propeller hole to move around its circular

motion easily translates into rotation for the propeller.

But why does putting a finger on the side lead to circular motion in the first place?

Well there have been many many papers written about how a hui stick works and they don't

Many explanations just simply say that it happens and they don't get into the actual

mechanism but I've done a few experiments on my own and I'd like to present some of

my findings and this is what I believe is important in the functioning of a proper hui

I believe that it doesn't just matter which side left or right you press a finger against.

It also matters which side top or bottom your finger is pressing against.

Let's pretend that this circle is a front on view of the propeller stick like this right?