I finally got myself a
fidget Spinner. Let's
open it up and
take a look. So, I guess you just hold it and...
Oh, Okay, I can... I can see why that is quite popular, it's...
Basically it's a little handheld gyroscope. That's awesome!
The question now is: how fast can one of these possibly go? So the fidget spinner
produces a slight hum as it spins so
what we can do is get a spectral analyzer
and see if we can pick up the frequency it's
spinning at. So this is just my
phone I have a
spectral app on here.
We have the frequency it can pick up on a horizontal axis in Hertz
and we have how loud that frequency is on the vertical axis, so if I whistle
[Whistling]
There we go, one little spike
[Whistling]
or if I try and generate more of a humming tone
[Humming]
[higher-pitched Humming]
We get lots of Harmonic spikes. I'm never going to do that again.
Okay now: I set it spinning, and we'll pick up with the frequency how fast it's going. So...
I think the problem is this is simply not going fast enough, and it's not stable enough
point glass and some Blue Tac
[Grunts] that
Now, I've seen my fair share of YouTube videos,
I know how to make something spin faster,
you use compressed air.
I haven't gotten air compressor
but I have got a can of pre-compressed air
that it turns out you can just buy off the internet.
I've also seen enough videos to know how this goes wrong,
so I have a safety shield for my face.
So I'm going to use the compressed air to speed up the fidget spinner,
and then we'll try and get a frequency reading of just how fast
it is going.
Here we are.
[Quiet whirring]
Ah! Oh, that's not bad.
Okay, here we go.
So, to make it a little bit clearer what's going on,
I'm going to switch from this view
which gives you all of it at once
to a wonderful rolling spectrogram view.
So now we get, um, time scrolling along;
we get intensity in terms of color, and frequency on the vertical axis this time.
So we should see a solid bold line for the main
frequency, and then we'll see the harmonics
stacked on top of that.
So, let's give it another go.
Right. This is the main event; I'm recording the data.
I'm going to set it spinning because
this is our serious trial.
It's time for maximum speed
with two cans!
Alright, here we go. Here we go.
[Whirring]
Okay, you can see the frequency.
There's the main one at the bottom there.
Whoa, and it's going up.
Come on, faster!
[Whirring]
Faster!
[Whirring]
Come on!
[Whirring]
Come on!
Okay, I think that we had a peak there. This is a scale of
ouch, okay, um, a scale of 0 to 225, 250 and that I think I pick was about the middle of that top range
so we'll we'll look it up. There we go. And see just how fast we were spinning. Okay, on the playback,
let's set it go. There we go.
Why am I still wearing this? Okay, so this is the playback
and you can see there's our big peak so I will pause it there and you can see the scale goes 0 to
250 and I'd say that's pretty much
spot-on
3/4 of the way up. 3/4 of
250 means it was going about 187.5 Hertz.
But we've now got our frequency, now here the thing about the fidget spinner: it's got three lobes and
the air is hitting each one is it goes by so I'm going to divide that
187.5 by 362.5 Hertz,
so now we just need to know how fast the tips of the spinner were going. Radius of
4 centimeters.
2 pi times 4 centimeters times 602.5 times a second
means that the tips of my visit spinner were going
1571 cm/s.
Let's convert that into some better units. It equals 15.7 m/s which is
56.5 k/m; don't worry people who don't understand real units, that is 35.1 mph.
That's pretty fast and bear in mind that 62.5 Hertz
of this thing spinning is
3750 revolutions per minute
so we're talking like engine speeds and the tips of it are going pretty funny not outrageously fast
but pretty fast
for a toy.
So that is how fast you can get a fidget spinner
going, do get one of the spectral apps, there are free versions available. You can play with them
have a look what happens when you sing or
record different notes and frequencies and things moving into them.
It's kind of a, as a gateway activity to fourier analysis, so I highly recommend it. As always
thank you so much to everyone who watches and likes and everything else these
videos and of course subscribe to the channel, blah, blah, blah, but I'm not really paying attention anymore because I've got one last
if it works:
a gyroscopic thing I'm going to see if I can get some gyroscopic precession
I don't know if I can get it going fast enough not...
We'll give it a go, oh,
let's put it. Let's put it on a GoPro. All right now. Now. This is a Youtube video, here we go
[Whirring]
Come on. Come on
[Whirring]
Change of the can
Yes! [Laughs]
Ah, sort of...
[Sound of fidget spinner hitting the table]