Dr Michelle Dickinson: nanotechnologist explains the physics behind successful hula hooping

Hula-hooping is a popular and seemingly simple activity that many children can do. However, the physics behind what makes a good hula-hooper has only just been studied with the first to mathematical explanation of hula-hooping dynamics published this week in the journal Proceedings of the National Academy of Sciences.

The research not only found what keeps a hula-hoop spinning against gravity but also reveal why some people find it easier than others - and body shape does matter! 

The researchers used robotic models with different 3D-printed body shapes including cylinders, cones, and hourglasses to replicate hula-hooping motions. Using high-speed video analysis, they found that while twirling a hoop was straightforward across body types, keeping it elevated against gravity required a specific body shape. Bodies with sloping hips to push the hoop upward and curvy waists to hold it in place were most effective. The research shows that while all body shapes are able to hula-hoop, those with an hourglass or pear-shaped body will find it easier than those with a straight or apple shaped figure. 

The researchers also looked at the best way to start hula-hooping and determined that the launch speed is crucial: if it's too slow, or combined with a gyrating motion that's too slow, the hoop simply falls off. 

While studying hula-hooping sounds like fun, the research also has practical implications to inspire innovations in energy harvesting from vibrations and improve robotic positioners used in industrial applications. 

LISTEN ABOVE

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudgin
from News Talks EDB.

Speaker 2 (00:12):
Joining me now with our son's study of the week
is now a Girl Doctor Michel de Consern. Good morning,
Good morning hula hooping.

Speaker 3 (00:19):
Can you do it?

Speaker 2 (00:20):
Yeah? Oh, got the hoops for it.

Speaker 3 (00:22):
Did you do it as a kid?

Speaker 2 (00:23):
Yes? Yes, used to love it? Yeah, you know, and
then you could do it around your head and it
wasn't just round your waist either. You'd do it around
your head, round your foot, you know, you'd sort of
skip over it round your foot.

Speaker 3 (00:31):
I have no, I can't look. I had a hooloop
as a kid, and I've tried as an adult, and
it's almost impossible.

Speaker 2 (00:37):
There are going You've taken this too far, But there.

Speaker 3 (00:40):
Seems to be like a group of people who can
hula hoop and those of us who can't hoop, and
like we wiggle around and I'm doing what seems to
be what everybody else is doing, just like moving my
tummy and moving my bomb, but my holy hoop just
falls to the ground. And the reason why we're talking
about this is there's a beautiful study that has come
out this week and it is in the journal Proceedings
of National Academy of Sciences p NAS. It's an open

(01:03):
source one. I love it because it's filled of fun
videos and actually I've really enjoyed watching the videos on this.
If you've got nothing to do on a rainy Sunday,
go check this out. The paper is titled Geometrically modulated
contact forces enable hula hoop Levitation. But basically what they've
done is they've built hula hooping robots of different shapes

(01:23):
and size that gyroid at the perfect frequency that you need. Basically,
they're wiggling around and they've thrown these hula hoops on
them to determine the three D physics of hula hooping,
which apparently we never knew until this paper was out.
We've only modeled it under a two D function before.
And now these amazing physicists and mathematicians have gone, do

(01:45):
you know what, we should probably understand the physics of
hula hooping a little bit better? To you three D
printed these models of different body shapes. So you've got
a cylindrical, You've got an hourglass shaped, you've got a
pear shaped, you've got an apple shaped. Basically all of
the human body types, and they've thrown a hula hoop
on it and then got a human to initiate the spin,

(02:05):
and then the robot to wiggle and jiggle and try
and understand the physics of hulo hooping.

Speaker 2 (02:10):
It's very cute to me, it is.

Speaker 3 (02:12):
And what they found is what they didn't realize before,
is there's two things. And now I know this, I'm
going to go home and try hula hooping agar in
because now I understand the science of it. Two things
that are more mean successful hula hooping. And the first
one is how fast you spin it. At the beginning,
You've got to fin it really small.

Speaker 2 (02:31):
Oh, you got to sort of flick around.

Speaker 3 (02:34):
If you don't do it fast enough, you doomed from
the star. Didn't know that. Number two, you've got to
gyrate yourself fast enough while you're spinning it fast enough,
so don't be all lazy off spin it or maybe
I'll catch up with my body. No, you've got to
spin your body as fast as spinning the hulub. But
number three, and this is where we can all go.
Do you know what hula hooping's not for me? It

(02:54):
definitely depends on body shape, So if you have an
hour glass figure or a pair shape figure, it's going
to be much easier for you to hula hoop naturally
than if you're an apple or if you're just straight up.

Speaker 2 (03:07):
Or down, because the iemy of there is that most
kids are just stried up and down. Like when I
was doing it as a kid, I was pretty much
trying up and down. It'll be a different story now,
wait going on. But I definitely got the thrower and
got moving straight away. I've just got this image of
you just standing there, not moving, kind of sort of
giving it a bit of a push around the body
and it's falling to the ground. See, yeah, I'm reackon.

(03:27):
You don't need together this another world.

Speaker 3 (03:28):
Well, now I know the physics out there, I can
put all and now I can run an experiment. I'm like,
I'm gonna go home. I'm going to hoop. If you're
watching my Instagram stories, this maybe what I'm doing. But
I love the fact that we didn't really understand hula
hooping until this week. We just never did a three
D model. We never built a three D robot that
could huloup and then spun it around. And you're like
Michelle Why are we wasting money on this research? There

(03:49):
are lots of things in engineering that spin around using
rings or hoops, and so actually hula hooping really does
defy gravity when you think about it, and so it's
about how do we use this in an engineering form
to actually keep things levitating or whatever we want to do.
So it's great for sights, but it's lovely. Go have
a look at these videos, these little hula hooping robots.

(04:11):
They're quite fun and it might inspire you even as
an adult, to go I might bring out the hula
hoop again.

Speaker 2 (04:16):
Nope, head into the garage, find that little hula hope
that's heading away and give it a world today. Thank
you so much, Michelle.

Speaker 1 (04:21):
For more from the Sunday Session with Francesca Rudkin, listen
live to News Talks it'd be from nine am Sunday,
or follow the podcast on iHeartRadio