August 3, 2025 • 32 mins
A few weeks ago, we had the amazing physicist, science writer, and communicator Laurie Winkless on the podcast. She was so great, one episode wasn’t enough... so she’s back to do some mythbusting!
In this episode we talk about:
- If glass is really a liquid
- A bunch of physics myths that have been debunked
- What 5G actually is and whether 5G towers kill or control people
- How microwaves work and if they are safe
- Whether you can use your mobile phone at petrol stations
- If you really need to turn off your phone on a plane
- Whether a plane toilet could suck your innards out (yes, really)
- If you are safe in a car during a lightning storm
- What would happen if you dropped a coin from a building... would it slice through someone?
- And even what happens if you stick toast to a cat
Quotes from the episode:
“People want simple answers, and the reality is that few things are simple.”
“The less you know, the more arrogant you are about the little bit you know.”
More about Laurie
Find her via her website or on social media.
You can get involved with the podcast online too of course.
Find our full podcast via the website here: https://www.nowthatwhatsicall.com
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For our latest big project, find out more about Incrediballs here: https://incrediballs.com/
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:05):
Kyoto Kaitaki and welcome to NowThat's what I Call Green.
I'm your host, Brianne W, an environmentalist and
entrepreneur trying to get you as excited about our planet as I
am. I'm all about creating a
scientific approach to making the world a better place without
the judgement and making it fun.And of course, we will be
chatting about some of the most amazing creatures we share our
planet with. So if you are looking to
(00:26):
navigate through everything green or not so green, you have
come to the right place. Something that I think a lot of
people have heard or feel like they know, which is actually
wrong, is that glass in old windows are thicker at the
bottom and thinner at the top because glass is some sort of
liquid that just flows over a really long time scale.
(00:49):
But that's not really true. Yeah, I'm afraid not.
I. Feel lied to.
Scientists have looked into this, right?
So there's actually been measurements done and proper
research done into this. And back in the 90s, there was a
paper from a Brazilian researcher and he basically
wanted to debunk this idea that old glass is thicker at the
bottom because it has flowed over time.
And he looked at a series of different glass compositions
(01:12):
over the years, mostly kind of in theory rather than in
practice, but looking at their chemistry.
And he figured out that you would need to get glass, I think
it's to 200 or 250° C before youwould see any sort of actual,
you know, flow. So we can turn glass into a
liquid the flows, but at room temperature it does not.
And then about 10 years ago, researchers who really know
(01:34):
glass who are at a company called Corning in the US, So
they're like the Glass Research Institute for the world really.
They did a proper study. So they did a really detailed
study and they looked at glass. They actually looked
specifically at Westminster Abbey, so glass at Westminster
Abbey as an example for this theory.
And they found that at room temperature, glass cannot flow.
(01:55):
Now I will say that glass does have a lower viscosity than we
thought. Now, viscosity is something that
is it's resistance to flow, so it's stickiness.
So it has to be very gloopy. It has a high viscosity.
If it's very runny, it has a lowviscosity.
So glass is a little bit lower in viscosity than we had thought
previously before this research.But Even so, they found that
(02:18):
glass will flow about 1 nanometer in a billion years.
Yeah, OK. Super perceptible.
I don't think we can measure it Even so.
Yeah. So I'm afraid glass does not
flow. Well, so why is glass thicker at
the bottom? Is it just the way it was made?
Yeah. Probably, and it was probably
sensible from the viewpoint of the people who were installing
the glass to put the heavier bitdown the bottom.
(02:40):
It'd be just a bit more stable than having the heavier bit up
the top. So there are examples in some
castles and churches and things where the glass has been put up
the other way. So the flicker end is at the
top. And that was probably a bit of
carelessness on the behalf of the 1st and flooding it in.
So but. That's good, because that helps
to prove the theory as well, yeah.
Sorry to debunk that one becauseit comes up a lot.
(03:00):
It does. You've ruined my whole
understanding of glass. Apologies, it's.
I'm devastated. It's a very.
Complicated material really is. Yep, I have speed about probably
3, maybe 4 seconds of my entire life to think about glass
before. So it's good to expand our
horizons. Welcome back to Microgreens.
Today we are debunking a whole bunch of different physics myths
with Laurie, the physicist who was not at all boring, which I
(03:22):
should stop saying that. So thank you for joining and
putting up with I think what an hour and a half long of which
ring on about things last week and thank you for coming back
my. Pleasure.
I've written a bunch of different myths for you and I
have allowed Laurie to have a look at these, so we're not
springing them on here because that probably a little bit
harsh. Now.
This one comes up a lot. It's potentially conspiracy.
It is conspiracy theories. Do 5G towers kill and control
(03:43):
people? Do they melt your brain?
No. Is it straight answer?
I'm surprised. I know you're shocked, but I do
think it's probably valuable to kind of take a wee step back and
talk about what 5G actually is. So the universe is full of
electromagnetic radiation. So this is energy that travels
through space in the form of waves, and there are loads of
(04:04):
forms of it. Now, there are loads of ways
that we can categorize electromagnetic radiation.
But if we're thinking about human health, if we're thinking
about making people sick, the best way or the most important
way to categorize it is whether it is ionizing or non ionizing.
And what defines that is the wavelength of the radiation or
(04:25):
how much energy it has. So most of the radiation that we
would interact with on an everyday basis, it has kind of
longer wavelengths, it has low energy.
So this is stuff like microwaves, radio waves, visible
light, These are all kind of lowenergy non ionizing radiation.
And they're called non ionizing radiation because this form of
(04:47):
radiation literally does not have enough energy to be ripping
electrons off atoms or to be breaking chemical bonds.
And that means that it it cannotdo damage to our cells, it
cannot do anything to our cells.It does not have that energy. 5G
is a form of non ionizing radiation.
So it sits somewhere between radio waves and microwaves on
(05:10):
the scale. So if we put, you know, all of
electromagnetic radiation on thescale with low energy non
ionizing radiation on the left and high energy ionizing
radiation on the right, 5G is down in that left section.
So it does not have the energy to damage our DNA or, or to do
anything like that. There are of course, forms of
(05:31):
radiation that can do that, right?
We have up on the right end of the scale, we've got ionizing
radiation. We've got things like X-rays,
uh, like CT scanners, they produce a form of ionizing
radiation that with a high enough dose can cause damage to
our bodies. So This is why, you know,
doctors try to limit how many X-rays you will get in a year or
in your lifetime. The dose you get is tiny, tiny,
(05:53):
tiny, tiny. But it's still enough that we
don't want to take that risk. So these are all these forms of
radiation. 5G is right down in the non ionizing low energy, not
going to RIP apart atoms, not going to RIP apart DNA.
End of the scale. So no, 5G will not give you
cancer and make you sick. I don't know why I have a weird
fascination radiation. I'm quite excited.
(06:15):
I have my, what do you call the student advisor at university to
allow me to do a radiation paper?
She's like, you've done no physics, so you want to do a 400
level radiation paper. OK, it's going to be fun, but
it's fascinating. And so I did a mini series on
nuclear energy in the first episode is specifically on
radiation. Now, Lori, you do not go listen
(06:35):
to it because you'll probably belike, not how I'd have worded
it, but if you are interested inthe basics of radiation, you may
find that useful because it goesinto the nitty gritty and also
it goes without saying that without causing damage to DNA,
it doesn't control. Us, No, I mean, we can't.
Like we don't have the ability to mind control.
We don't have technology to control.
People, all that we know. About that we know about.
Yeah, of course, but it's reallydifficult to do, man.
(06:58):
The brain is incredibly complicated.
Yeah, yeah, incredibly complicated, but also we can be
incredibly stupid at the same time.
It's amazing, isn't it, that those two things exist?
Simultaneously, so this is another one that you hear a lot
of people mention and it's very much the same answer.
Microwaves, you don't have to worry about.
People don't like to stand in front of them because they're
worried about radiation leakage,but it's a completely incorrect
(07:19):
or the wrong wavelength for that.
Yeah, it is. It's right down there in that
non ionizing end of the spectrum, so it can't do
anything to you. And the other thing is that
microwave ovens have been designed to keep microwaves
inside them. So they all have a metallic cage
built into it. Even through the glass.
There's a cage in there that keeps the microwaves inside the
microwave oven. Is it?
(07:39):
Saturday caters a different thing.
Yeah, it kind of is, but it's for microwaves specifically.
So it's kind of designed for those wavelengths.
And the reason I think what people get a bit worried about
is because they think, you know,a microwave is where you cook
food. And that's probably bad for
ourselves somehow if it's sneaksout.
But what a microwave is doing when it's cooking food is it's
(08:00):
heating up the water inside the food.
So that's what a microwave does.It heats up the water and gives
the water inside your food energy that heats up the rest of
your food. So it's not doing anything.
It's not like, again, it's not damaging any sort of, it's not
doing any chemistry. I guess it's just warming stuff
up. So yeah, there's no, we don't
have any reason to be concerned standing in front of like a
(08:21):
modern day microwave oven. It's completely safe.
You say modern day. Yeah, well, you know, stuff
rusts, stuff breaks, you might get some damage, but Even so,
microwaves aren't going to do anything to you.
No, because it's not the right kind of right.
And that's the key is these things, because they are
technically a form does not meanthey are the right form.
I think it'd be good if people understood the difference
(08:42):
between ionizing and non ionizing.
And actually I noticed this warning sign no longer seems to
appear, but on the forecourts ofpetrol stations.
It used to say don't use your mobile phone because of the
likelihood, I think of them creating a spark.
Yeah. So first of all, we don't
produce sparks when we use our mobile phone.
So that I think is probably the I would.
(09:04):
Have thought we'd have noticed. Yeah, I would have thought so
too. But we can produce sparks on a
petrol station forecourt if we are not careful, but not
generally because of our mobile phone.
Now I will say that I did look into this because I didn't know
whether this had ever been reported as ever having happened
before. There's been, from what I could
find there was like this has never happened.
(09:25):
So we've never had a situation where a spark or something else
from a mobile phone has caused afire on a petrol station
forecourt, Right. So it's never happened.
I have read a bit about like some of the cautiousness around
using mobile phones is partly todo with timing.
Like when we started to get mobile phones, it was also at
the same time as we were starting to get like more
(09:47):
electronics within our petrol pumps.
And I think there was some concern that like the mobile
phone was somehow interfering with the electronics in the
petrol forecourt, you know, in the early days of mobile phone
technology. So I think maybe that's where
the initial concern from a petrol station owner viewpoint
maybe came from. But what we do see is that a
(10:08):
spark can and does cause like a flammable vapor, like the vapor
that you'd have at the end of the fuel nozzle that can cause
that to ignite. So something you don't want to
do ever, for example, is have your Jerry can that you're
refilling from the petrol station, sitting in the boot of
your car where there's very often carpet because you can get
(10:30):
charges building up between the materials.
You can get a spark in that situation.
And actually this has happened alot.
So you can have people being notvery careful with the way
they're handling their Jerry cans on a petrol station.
Ford Court can lead to fires andhas led to fires.
There's been lots of reports in Australia, for example, of stuff
like this. So sparks, yes, can cause
(10:52):
flames. Mobile phones don't really
'cause sparks. So there's kind of a disconnect
between those two parts of the of the myth.
But I kind of understand where it comes from to be honest.
There's also arguments to just not use your mobile phone
because you'll be distracted, you know?
What if someone drives in, you know?
So it's not bad advice, but it'smaybe not for the reasons given
or you'd expect. Yeah, yeah.
(11:13):
I always wondered if it was something to do because
obviously used to have a separate phone.
Got 412 years ago, separate battery from a phone, right?
Oh yeah. I don't know if I ever had one
of those or not. I don't recall, but I think the
some of the concern with dropping it and spiking on the
ground. But yeah, you could say that
about almost anything like the metallic element, I would have
thought. Yeah, quite like you can
generate sparks quite easily. Hmm.
(11:33):
So I feel like we've kind of blamed the mobile phone for
something that we are perfectly capable of doing incompetently.
Mobile phones on planes, yeah. I am of the firm belief if it
was a real concern they would take your phone off you or as
I've recently learnt existed, they'd put them in Faraday bags,
which are a thing. Yeah.
I don't know if you know enough to comment on the airplane if I.
(11:54):
Like remember vaguely reading about it a long time ago and I
kind of I'm of the same frame ofmind.
I suspect that if you're like really up close to the cockpit,
maybe it might have, there's a possibility of some
interference. But usually with the stuff, you
know, we've got very narrow welldefined wavelength ranges that
our technology operates at. And you know, like you said,
(12:17):
unless it was an extreme risk, Ithink they would take our phones
off as if it was an extreme risk.
I think they would. But I mean, I generally just
don't use it and I'm never near the front of the plane.
So I think it's just a habit. I'm not convinced that it's
going to cause a plane to fall out of the air.
But could it interfere? Maybe, You know, if the
wavelengths overlap, if the wavelengths in, you know, our
(12:39):
broadcast spectrum of our phone and whatever all of the
electronics in the cockpit, if they overlap, then, yeah,
there's a possibility they will interfere.
Yeah, I just keep it off. Absolutely.
Look, at the end of the day, if you don't know enough, don't
bugger around with the rules because it's a plane.
Air on the side of caution. Yeah, I.
Think that's a good rule when a plane in general really.
Definitely. Continuing on with the plane
(13:01):
theme, can a plane toilet suck your innards out?
I don't know what the what the myth is here, but apparently
this is the thing people are concerned about.
It's being sucked into the toilet or being like
disemboweled. Yeah, I don't want to.
That's a horrible scene in what are those Final Destination
Horrible, horrible scene where aman is disembowel by a swimming
pool pump. Oh God.
You know, is there something else I have to fresh about?
(13:21):
I would say no, you don't need to worry about this.
And I think the reason that you don't have to worry about it is
that the only way there's any sort of risk, and it's a very
minor risk even at this, would be if you managed to create a
perfect seal with your buttocks on the toilet seat, right?
You can't do that. The toilet seats have a gap in
them on a plane, probably for that reason.
(13:43):
Oh yeah, no disembowelling. Yeah.
So I think that's not going to happen.
I've never again, there's no reports of it ever happening
ever. They've.
Covered it up, You see the same 5G.
And yeah, I'm sorry, I should stop mocking people.
That's terrible. That's all part of this
conspiracy. But no, I think basically that's
never going to happen. So you have to get a perfect
seal with your buttocks and thenwhen the vacuum is turned on, it
(14:06):
might suck some of your skin a bit further in, maybe, but it's
not going to be powerful enough to to disembowel your.
And also by the way, by the way,an airplane toilet, the stuff
that goes down the toilet is stored.
It is not ejected out of the plane, which is another myth
that you see sometimes that people think, yeah, yeah, no,
that doesn't happen. So I think you're safe.
(14:28):
I. Didn't know people thought that
was a thing. That whole just dropping it, I
just don't see countries allowing that to just be dropped
to Willy nilly. But OK, so it's not.
And if so, if you were sucked into the toilet slightly, it
would be maybe by a couple of millimetres.
But it's only if you can get this perfect seal in place.
Yeah, which you can't. Yeah, no, OK.
(14:48):
Thankfully I can take that off. The don't have to be worried
about list being in a car in a storm.
You always assume because I havedriven through the most
spectacular lightning storm and it's slightly unnerving because
you know, electricity is especially my great uncle was
hit by lightning twice. Oh.
My God. He survived.
I know. Honestly, I thought this was ABS
family myth, but it is actually true.
(15:09):
It's kind of goodness. Yeah.
But in a big electrical storm, other than being beautiful, you,
you. It's unnerving.
We all feel a little bit safer because of the tires, I think.
Is that a reality or are we lesssafe?
You are safe in a car in a storm, but not because of the
tires. It's because your car acts as a
Faraday cage. So assuming your car is a metal
(15:30):
cage is a metal chassis, then what will happen is if lightning
does strike your vehicle, which you know the risk of.
That is already pretty small, but if it does strike your
vehicle, the lightning will takethe easiest path and that's
through a metal. So all of the charges will stay
on the outside of the car and make their way to the ground.
So it's not to do with the tiresat all.
Where things get a bit complicated is if you have like
(15:52):
a a convertible car which doesn't have a metal roof, for
example, arguably that it definitely will not be acting as
a Faraday cage because it needs to have a clear path, like it
needs to have a continuous path of the metal.
So, you know, maybe you're less safe in a convertible car, even
with the roof up in a lightning storm.
But yeah, it's all about the metal, really.
(16:13):
It's all about the chassis and not really about the tires at
all. You know, that makes sense to
actually thinking about it. Yeah, electricity is a weird
thing. You know, we have this
relationship with this, and it'salso kind of a bit terrifying
and mysterious. So I understand the thing about
thinking that because rubber is an insulator on some level that
maybe that protects you. But actually what you want is
(16:35):
for the electricity to flow justnot through you.
You want the electricity to flowsomewhere else.
And thankfully in a metal car, that is exactly what it'll do.
So you're pretty? Safe in it, Yeah.
OK, so even though you've got that rubber instead of what?
Yeah, you think the actual rubber itself and the charge
leaps to ground, Yeah. Usually because you're really,
it's such a short distance, you know, So, yeah.
(16:55):
All right, OK. And lightning is negatively
charged clouds positively charged, Earth I.
Believe so. Yeah.
Yeah. And there is somewhere, and I've
forgotten where it is in the world, that gets almost all year
round. It has something like 200
lightning strikes an hour for something about 250 days a year.
And I can't remember where it is, but it.
Must be like rainforest. Yeah, I would think.
It's certainly a tropical environment.
(17:15):
I probably should have found outwhere that was.
Yeah, very cool. If I dropped a coin from the Sky
Tower in Auckland, would I slicethrough somebody?
This is another Final Destination thing actually.
I think the answer to this is no.
Now I've kind of gone around thehouses on this, partly because
aerodynamics is, is quite complicated.
You know, I was like, oh, I'll just do like a quick calculation
(17:36):
just to see, you know? Oh, you did.
OK, Oh, maths. Oh yeah.
Well, you know, if I have numbers, I will try and do a
calculation, but I think the answer is no.
But I think once you start getting bigger, heavier objects
than say a coin, then the risk becomes much greater.
So when you drop something from a building, it's moving through
(17:57):
the air as it's moving at a constant acceleration.
So it's moving at the speed of gravity, which means that its
speed is increasing at a constant rate, which is a a
weird thing sometimes for peopleto get their head around.
It is moving through the air. So it's bashing through air
molecules. It's not moving through a
vacuum. So you end up reaching what's
called a terminal velocity, which is where the air
(18:18):
resistance. So the the drag that's caused by
moving through the air, trying to push the air molecules out of
the way. That kind of balances with the
gravitational force on the coin,right?
So the speed of the coin moving through the air.
Now where it gets complicated islike you've got these things
called drag coefficients. So this tells you how easily or
how difficult it is for a shape of an object to move through air
(18:42):
or water. So there's a reason that like
planes are the shape they are because that minimizes what we
call the drag coefficient. A big ball, for example, will
risk experience a lot more drag than a sleek airplane.
And a coin is funny because a coin kind of is thin, small, it
will flip over I would expect asit's falling.
So it's actually quite difficultto calculate what it's drag
(19:03):
coefficient is. So This is why I'm kind of going
around the houses a bit. But basically from what I can
figure out, you've got like a 1 cent coin in New Zealand weighs
about two grams, $1.00 coin weighs about 8g.
They're very small. You know, they're like 10s of
millimeters in diameter. They're thin.
So I think that even when they're moving fast, I don't
(19:25):
think they're going to, they're definitely not going to slice
through you. Am I hurt a bit if it hits you
like, but I don't think it's going to like injure you.
But yeah, when stuff gets biggerand heavier, then the speed that
it reaches, the energy it has when it hits the ground is, is
much higher. So then it gets quite risky.
But I did look up because I wanted to see, I'm sure I knew
that someone would have done this calculation about
(19:46):
hailstones, right? Because hailstones are a thing
that we're obsessed with. And a hailstone with a radius of
about 5 centimeters, so a 10 centimeter diameter.
So a big hailstone would have like a terminal velocity of
close to 50 kilometers an hour so that, you know it would hurt
you, but it's not going to slicethrough you.
And that's a relatively easy thing to calculate because it's
(20:07):
a ball, it's a sphere. But Even so, things like.
Humidity will make a difference to how objects move through air,
so it's really difficult to giggly, but I think it's
definitely not going to slice through.
It might hurt you a bit. If it hits you, unfortunately
you have just now ruined the latest Final Destination movie.
Really. Because the precursor is a bit
of a coin. Because I was assumed there'd be
(20:27):
a bit of sort of path of least resistance that it would fall
through. Because obviously flipping over
at one point, you'd have more force.
I do not like talking about thiswhen I had no idea what I'm
talking about. To you.
This is quite stressful. But I just assumed it would be
easier for it to fall that way. Yeah.
And therefore it would gain a bit more speed.
Obviously not. It tends to flip, yeah.
It tends to move around a bit, and you'll have objects like a
(20:47):
dart, for example. Like a dart will tend to fall in
One Direction. It will point straight down at
the ground. But that's again because of what
we call its drag coefficient. It's got this narrow long body,
so it will fall on that like least resistance kind of path.
But we just don't have any like preference to the way that
things tumble, especially like if we accelerate something, if
(21:08):
we like launch something, it will usually stay in its
position because we've given it energy and it will hold that
position. But when you're dropping
something, you're just kind of like hands off and it will
tumble and it will move and it will be buffeted by the air if
there's any breeze or wind. Like all of those things can
interfere with how an object falls.
Would it be different in a vacuum?
Yeah, it would definitely be. If it fell through a vacuum, it
(21:29):
would probably kill you. Yeah.
Oh. OK, OK, OK.
The last question is really weird, and I think it actually
comes from a Simpsons joke. You know how toast always lands
buttered side down? Yeah.
Yeah. And cats always land legs up,
down, standing up. So what happens, the age-old
joke, if you glue a piece of buttered toast to a cat?
Yeah. Does it infinitely rotate?
Exactly. That's exactly what it does in
(21:51):
terms of physics. Yeah, I can confirm.
If only, why do cats always landon their feet?
I think just because they think quicker than us, I don't really
know, Like I think they have a asense of where their body is.
There's a thing called proprioception, which was not
something that I'd ever heard about until quite recently,
which is like a sense of where your body is in space.
So like really good athletes, for example, it's.
(22:13):
Very important and we don't train it, but we should.
No, not at all. And like very good athletes have
incredibly good proprioception. They know where their limbs are
and and where everything is. And you know, you'll see this
like I'm a big rugby fan, You'llsee this like in a rugby match
where you've got someone at the bottom of a of a mole and
they've managed to somehow know where the try line is.
Like even though their body, they've been flipped over and
(22:35):
stumbled to the ground, but theyknow where the line is.
And I think like with cats, I kind of just have AI get a sense
does not based on physics that they have incredibly good
proprioceptions so they can see where the floor is or know where
the floor is and they can rotatetheir body to meet it.
Toast of course, does not have any proprioception because it's
not. I think the buttered side down
(22:55):
thing I think is just because ofthe height of most tables.
Yes, it's all about what 1.3 is 1.5 it's just a number of
rotations I. Think yeah, maybe we should do
some experiments with like dropping it from higher heights.
Please make sure you you film those because I think it would
be quite funny, particularly to clean up afterwards.
It's super annoying. If you stick it on to the back
of a cat, then obviously what will happen is that the butter
(23:15):
side toast will want to hit the ground, The cat will want to hit
the ground also. So they kind of infinitely just
cycle and become a perpetual motion machine, yeah.
Yeah, well, we've solved the energy crisis.
Done. Congratulations.
You probably get your doctorate written very easily from 9:00 PM
the night before, I think. Yeah, super.
So just jot this down. Look, I have heard of all sorts
of absolutely insane things online that people vehemently
(23:38):
believe. Perpetual motion cat toast
machine is not the weirdest. It could be worse.
The other day I was trying to explain to someone why a water
powered engine or a water powered car won't work.
Yeah, and I understand that if you run electricity, you split
water and then you can burn the hydrogen and the oxygen is
there. You try and tell people, but
splitting water actually uses more energy than is released.
(23:59):
Yes. And people are like, oh, but you
just use electricity to split the water.
OK, so the electricity comes from.
No, I haven't convinced anybody of my argument at.
All no. But it's hard.
And I think anything to do with energy is hard because I think
we don't teach it well. Maybe I don't know.
And I think also people want simple answers.
And the reality is that few things are simple, most things
(24:22):
are complicated. And that's why you need experts
who are working on these challenges rather than randoms
reckoning that they have an idea.
And it's not to discourage people having ideas.
Like ideas. Ideas are great.
But science is about testing ideas.
So yeah, the ones that work stick around.
The other ones don't. Exactly.
Do you have a cat? I don't have a dog though.
(24:43):
OK, Dogs unfortunately don't land on their feet, so if you're
going to test that one, I'm going to need you to get a cat.
Yeah. I'll go in next door.
They have a cat, yeah. Perfect.
Yeah, make sure you film that experiment because that will be
really interesting to watch. You stick some toast to a cat I.
Think we'll just like, wrap it around its waist?
Maybe they look a little belt like a saddle.
So the toast is like a saddle. It would be lovely.
(25:05):
Oh God, you can tell it's Friday.
We've gone completely crazy. Well, do you have any other
random myths do you want to bust?
No, I don't think so. I mean, like, the world is full
of interesting myths. I'll tell you like a random cool
thing that I came across when I was writing sticky.
This is about plants. So I thought that maybe it's a
bit physics adjacent, but there's a plant called the
(25:26):
Salvinia Fern. It's actually like a horribly
invasive weed. It grows like crazy on
waterways, It chokes up waterways.
It's awful stuff. However, from a physics point of
view, it's really interesting because it has the leaves of
these ferns are covered in thesestructures and they kind of look
a bit like a whisk, like a baking whisk.
So like a long stem and then a kind of a four strips joining it
(25:48):
together at the top. So like a bubble whisk.
And these plants are really interesting because they float
on the water and they don't get wet, right?
So you could submerge this Fernan water for literal years
and you pull it out of the waterand it will be bone dry.
So it is water repellent. But a few years ago, scientists
kind of finally figured out how this particular plant is so
(26:09):
water repellent. And it's because these whisk
structures, they're covered in amaterial, a kind of a waxy
material that stops water from sticking to the leaf.
But the genius bit is at the very tip of the whisk, there's a
tiny little section that is actually water attracting.
So it's hydrophilic, that's whatwe call it in physics terms.
So it's attracting the water at the tip, but all the rest of the
(26:32):
leaf, all the rest of the structures are repelling the
water. So what that means is when you
put it into the water, air surrounds the leaf, but then
water gets pinned onto the very top of each one of these tiny
structures, these whisk structures.
So the water actually gets pinned, and it traps this layer
of air inside the Fern. So when you lift it out of the
water, it's only that tiny, tinytip that ever had water touching
(26:55):
it, ever had water kind of stuckto it.
And the scientists who discovered this are trying to
use it to basically develop coatings for boats so that you
could potentially have a boat that doesn't get wet.
So you have a boat that doesn't move through the water.
Yes, you have no fowling. It would help with speed.
Yep, It would definitely help with speed because you're moving
(27:18):
through the air rather than water.
So that's the goal. And this is what they're trying
to do. They're trying to make a coating
based on the same structure, this idea that, like, you stick
tiny bits of water, but you mostly repel water.
If you can do that on a coating,yeah, you can have a boat that,
like you said, doesn't fell, doesn't get actually wet.
It kind of floats, moves on a pocket of air and therefore uses
(27:39):
less fuel. So that would be super cool.
I'd love to see something come out of that.
Yeah. Also, as soon as you said it, I
thought that would resolve a lotof problems with packaging.
The reason we use plastic, of course, is because of so much of
our food or cosmetics or whatever contains water, so
cardboard and stuff doesn't work.
It was depending on a few things, if you could use
something like that as a coatingon the inside of a box or a
(28:00):
tube. Can we hurry this along to the
commercial? Yeah, let's have a chat.
Let's see if we can just fix it.Yeah, the weekend.
We've got the whole weekend, so two whole days.
And what do you want, really? Honestly.
So that water, is it also at allrelated to surface tension?
Yeah. So like water has quite a high
surface tension, so it kind of like it's not a skin, but it
behaves as if the layer that's touching something is stuck to
(28:24):
it. It's because it's got basically
the water molecules want to stick together really strongly.
So yeah, the surface tension does make a difference.
I don't actually know. I would love to see if anyone's
done the experiment rods in withwater, then with like something
like an alcohol, which will havea different surface tension.
Really interesting to see whether liquids like that would
wet this leaf rather than stay on the top of the leaf.
(28:47):
Yeah. So if the surface tension is
important, but I actually I don't know what it would mean in
this instance. Yeah, I think spiders are great.
I do really like them, but I really don't want them on me.
Fair enough. Freak me out a little bit.
Yeah, but I was. I'm cleaning out sort of the
pole. Well, I wasn't.
I was standing away in the corner going Oh my God, because
there was a massive spider walking along the bottom of it.
(29:07):
Oh God. And I did a bit of research
about spiders and even if they don't seem hairy, they often
trap. They can trap air around
themselves, but from surface tension and they can survive for
quite a while, which is really, really cool and also horrifying.
Yeah, it's true. I kind of feel like that
sometimes about the natural world and I think that's part of
in general, like why I feel veryill equipped sometimes to move
(29:28):
through the world because anything that's like alive.
The squishy things. Yeah, the squishy alive things,
I don't know, they're like magicor something.
Ultimately, though, because. I remember having a very
vociferous debate with an engineering flatmate, he said.
Ultimately everything is physics.
Yeah, it was very physics versusbiology.
I had an argument with a friend at university.
I mean, we're still friends, so it's fine, but she would say
(29:51):
like, because she's, well, just.And she would say, I just don't
know how you could, like, walk around in the world not
understanding how your body works.
And my incredibly arrogant response, as always.
Well, I don't know how you move through the universe without
understanding how it works, which I can.
I say I would never say that now.
I do not believe that, but yeah.It is almost like a the least
(30:12):
you know, the more arrogant you are about a little bit, you
know, right. That means to realise that oh
shit, you know nothing and you are an imbecile in the face of
everything. Did you say that astronomers saw
or it's not live? Obviously, it's just when it
gets to us. This or the formation of a
planet. No.
Yeah. So I only read the heading
because then I lost it and I can't find it again.
Yeah, they've got the the vision, the beginnings of a
(30:33):
planet, man. Yeah.
I don't know how they know because I imagine it takes eons
to form a planet I. Would think so, but how cool
that we have the ability to see things that far away and.
That long ago. Long ago, exactly.
We're getting into relativity. No, no, too confusing.
My brain will melt. Yeah, not for a Friday.
Well, there you go, there's yourweekly physics myth busting.
(30:55):
You can feel better about 5G's and airplane toilets.
Although to be honest, it wasn'tthe sucking thing that worried
me about plane toilets. It's the level of ick, yeah, and
I don't understand why there is always water on the floor.
I also feel convinced it's not water.
So. I'd like someone to explain to
me the physics of that. I don't want you to.
Please don't. I will tell you that the toilets
don't use water on a plane, so it's not from the toilet.
(31:16):
Also, it's definitely not water.It could be from the sink,
right? It's probably water from the
sink, that's sure. Sure it is.
Yeah. Yeah.
OK. We'll go with that.
Thank you again. Always fascinating, always a
pleasure. That has been your weekly
physics moment. Had a blast, thanks so much
friend. And there you go, I hope you
learned something and realise that being green isn't about
(31:38):
everything in your pantry matching with those silly glass
jars or living in a commune. If that's your jam, fabulous.
But sustainability at its part is just using what you need.
If you enjoyed this episode, please don't keep it to yourself
and feel free to drop me a rating and hit the subscribe
button Kyoda and I'll see you next week.
Kyoto Kaitaki and welcome to NowThat's what I Call Green.
I'm your host, Brianne W, an environmentalist and
entrepreneur trying to get you as excited about our planet as I
am. I'm all about creating a
scientific approach to making the world a better place without
the judgement and making it fun.And of course, we will be
chatting about some of the most amazing creatures we share our
planet with. So if you are looking to
(00:26):
navigate through everything green or not so green, you have
come to the right place. Something that I think a lot of
people have heard or feel like they know, which is actually
wrong, is that glass in old windows are thicker at the
bottom and thinner at the top because glass is some sort of
liquid that just flows over a really long time scale.
(00:49):
But that's not really true. Yeah, I'm afraid not.
I. Feel lied to.
Scientists have looked into this, right?
So there's actually been measurements done and proper
research done into this. And back in the 90s, there was a
paper from a Brazilian researcher and he basically
wanted to debunk this idea that old glass is thicker at the
bottom because it has flowed over time.
And he looked at a series of different glass compositions
(01:12):
over the years, mostly kind of in theory rather than in
practice, but looking at their chemistry.
And he figured out that you would need to get glass, I think
it's to 200 or 250° C before youwould see any sort of actual,
you know, flow. So we can turn glass into a
liquid the flows, but at room temperature it does not.
And then about 10 years ago, researchers who really know
(01:34):
glass who are at a company called Corning in the US, So
they're like the Glass Research Institute for the world really.
They did a proper study. So they did a really detailed
study and they looked at glass. They actually looked
specifically at Westminster Abbey, so glass at Westminster
Abbey as an example for this theory.
And they found that at room temperature, glass cannot flow.
(01:55):
Now I will say that glass does have a lower viscosity than we
thought. Now, viscosity is something that
is it's resistance to flow, so it's stickiness.
So it has to be very gloopy. It has a high viscosity.
If it's very runny, it has a lowviscosity.
So glass is a little bit lower in viscosity than we had thought
previously before this research.But Even so, they found that
(02:18):
glass will flow about 1 nanometer in a billion years.
Yeah, OK. Super perceptible.
I don't think we can measure it Even so.
Yeah. So I'm afraid glass does not
flow. Well, so why is glass thicker at
the bottom? Is it just the way it was made?
Yeah. Probably, and it was probably
sensible from the viewpoint of the people who were installing
the glass to put the heavier bitdown the bottom.
(02:40):
It'd be just a bit more stable than having the heavier bit up
the top. So there are examples in some
castles and churches and things where the glass has been put up
the other way. So the flicker end is at the
top. And that was probably a bit of
carelessness on the behalf of the 1st and flooding it in.
So but. That's good, because that helps
to prove the theory as well, yeah.
Sorry to debunk that one becauseit comes up a lot.
(03:00):
It does. You've ruined my whole
understanding of glass. Apologies, it's.
I'm devastated. It's a very.
Complicated material really is. Yep, I have speed about probably
3, maybe 4 seconds of my entire life to think about glass
before. So it's good to expand our
horizons. Welcome back to Microgreens.
Today we are debunking a whole bunch of different physics myths
with Laurie, the physicist who was not at all boring, which I
(03:22):
should stop saying that. So thank you for joining and
putting up with I think what an hour and a half long of which
ring on about things last week and thank you for coming back
my. Pleasure.
I've written a bunch of different myths for you and I
have allowed Laurie to have a look at these, so we're not
springing them on here because that probably a little bit
harsh. Now.
This one comes up a lot. It's potentially conspiracy.
It is conspiracy theories. Do 5G towers kill and control
(03:43):
people? Do they melt your brain?
No. Is it straight answer?
I'm surprised. I know you're shocked, but I do
think it's probably valuable to kind of take a wee step back and
talk about what 5G actually is. So the universe is full of
electromagnetic radiation. So this is energy that travels
through space in the form of waves, and there are loads of
(04:04):
forms of it. Now, there are loads of ways
that we can categorize electromagnetic radiation.
But if we're thinking about human health, if we're thinking
about making people sick, the best way or the most important
way to categorize it is whether it is ionizing or non ionizing.
And what defines that is the wavelength of the radiation or
(04:25):
how much energy it has. So most of the radiation that we
would interact with on an everyday basis, it has kind of
longer wavelengths, it has low energy.
So this is stuff like microwaves, radio waves, visible
light, These are all kind of lowenergy non ionizing radiation.
And they're called non ionizing radiation because this form of
(04:47):
radiation literally does not have enough energy to be ripping
electrons off atoms or to be breaking chemical bonds.
And that means that it it cannotdo damage to our cells, it
cannot do anything to our cells.It does not have that energy. 5G
is a form of non ionizing radiation.
So it sits somewhere between radio waves and microwaves on
(05:10):
the scale. So if we put, you know, all of
electromagnetic radiation on thescale with low energy non
ionizing radiation on the left and high energy ionizing
radiation on the right, 5G is down in that left section.
So it does not have the energy to damage our DNA or, or to do
anything like that. There are of course, forms of
(05:31):
radiation that can do that, right?
We have up on the right end of the scale, we've got ionizing
radiation. We've got things like X-rays,
uh, like CT scanners, they produce a form of ionizing
radiation that with a high enough dose can cause damage to
our bodies. So This is why, you know,
doctors try to limit how many X-rays you will get in a year or
in your lifetime. The dose you get is tiny, tiny,
(05:53):
tiny, tiny. But it's still enough that we
don't want to take that risk. So these are all these forms of
radiation. 5G is right down in the non ionizing low energy, not
going to RIP apart atoms, not going to RIP apart DNA.
End of the scale. So no, 5G will not give you
cancer and make you sick. I don't know why I have a weird
fascination radiation. I'm quite excited.
(06:15):
I have my, what do you call the student advisor at university to
allow me to do a radiation paper?
She's like, you've done no physics, so you want to do a 400
level radiation paper. OK, it's going to be fun, but
it's fascinating. And so I did a mini series on
nuclear energy in the first episode is specifically on
radiation. Now, Lori, you do not go listen
(06:35):
to it because you'll probably belike, not how I'd have worded
it, but if you are interested inthe basics of radiation, you may
find that useful because it goesinto the nitty gritty and also
it goes without saying that without causing damage to DNA,
it doesn't control. Us, No, I mean, we can't.
Like we don't have the ability to mind control.
We don't have technology to control.
People, all that we know. About that we know about.
Yeah, of course, but it's reallydifficult to do, man.
(06:58):
The brain is incredibly complicated.
Yeah, yeah, incredibly complicated, but also we can be
incredibly stupid at the same time.
It's amazing, isn't it, that those two things exist?
Simultaneously, so this is another one that you hear a lot
of people mention and it's very much the same answer.
Microwaves, you don't have to worry about.
People don't like to stand in front of them because they're
worried about radiation leakage,but it's a completely incorrect
(07:19):
or the wrong wavelength for that.
Yeah, it is. It's right down there in that
non ionizing end of the spectrum, so it can't do
anything to you. And the other thing is that
microwave ovens have been designed to keep microwaves
inside them. So they all have a metallic cage
built into it. Even through the glass.
There's a cage in there that keeps the microwaves inside the
microwave oven. Is it?
(07:39):
Saturday caters a different thing.
Yeah, it kind of is, but it's for microwaves specifically.
So it's kind of designed for those wavelengths.
And the reason I think what people get a bit worried about
is because they think, you know,a microwave is where you cook
food. And that's probably bad for
ourselves somehow if it's sneaksout.
But what a microwave is doing when it's cooking food is it's
(08:00):
heating up the water inside the food.
So that's what a microwave does.It heats up the water and gives
the water inside your food energy that heats up the rest of
your food. So it's not doing anything.
It's not like, again, it's not damaging any sort of, it's not
doing any chemistry. I guess it's just warming stuff
up. So yeah, there's no, we don't
have any reason to be concerned standing in front of like a
(08:21):
modern day microwave oven. It's completely safe.
You say modern day. Yeah, well, you know, stuff
rusts, stuff breaks, you might get some damage, but Even so,
microwaves aren't going to do anything to you.
No, because it's not the right kind of right.
And that's the key is these things, because they are
technically a form does not meanthey are the right form.
I think it'd be good if people understood the difference
(08:42):
between ionizing and non ionizing.
And actually I noticed this warning sign no longer seems to
appear, but on the forecourts ofpetrol stations.
It used to say don't use your mobile phone because of the
likelihood, I think of them creating a spark.
Yeah. So first of all, we don't
produce sparks when we use our mobile phone.
So that I think is probably the I would.
(09:04):
Have thought we'd have noticed. Yeah, I would have thought so
too. But we can produce sparks on a
petrol station forecourt if we are not careful, but not
generally because of our mobile phone.
Now I will say that I did look into this because I didn't know
whether this had ever been reported as ever having happened
before. There's been, from what I could
find there was like this has never happened.
(09:25):
So we've never had a situation where a spark or something else
from a mobile phone has caused afire on a petrol station
forecourt, Right. So it's never happened.
I have read a bit about like some of the cautiousness around
using mobile phones is partly todo with timing.
Like when we started to get mobile phones, it was also at
the same time as we were starting to get like more
(09:47):
electronics within our petrol pumps.
And I think there was some concern that like the mobile
phone was somehow interfering with the electronics in the
petrol forecourt, you know, in the early days of mobile phone
technology. So I think maybe that's where
the initial concern from a petrol station owner viewpoint
maybe came from. But what we do see is that a
(10:08):
spark can and does cause like a flammable vapor, like the vapor
that you'd have at the end of the fuel nozzle that can cause
that to ignite. So something you don't want to
do ever, for example, is have your Jerry can that you're
refilling from the petrol station, sitting in the boot of
your car where there's very often carpet because you can get
(10:30):
charges building up between the materials.
You can get a spark in that situation.
And actually this has happened alot.
So you can have people being notvery careful with the way
they're handling their Jerry cans on a petrol station.
Ford Court can lead to fires andhas led to fires.
There's been lots of reports in Australia, for example, of stuff
like this. So sparks, yes, can cause
(10:52):
flames. Mobile phones don't really
'cause sparks. So there's kind of a disconnect
between those two parts of the of the myth.
But I kind of understand where it comes from to be honest.
There's also arguments to just not use your mobile phone
because you'll be distracted, you know?
What if someone drives in, you know?
So it's not bad advice, but it'smaybe not for the reasons given
or you'd expect. Yeah, yeah.
(11:13):
I always wondered if it was something to do because
obviously used to have a separate phone.
Got 412 years ago, separate battery from a phone, right?
Oh yeah. I don't know if I ever had one
of those or not. I don't recall, but I think the
some of the concern with dropping it and spiking on the
ground. But yeah, you could say that
about almost anything like the metallic element, I would have
thought. Yeah, quite like you can
generate sparks quite easily. Hmm.
(11:33):
So I feel like we've kind of blamed the mobile phone for
something that we are perfectly capable of doing incompetently.
Mobile phones on planes, yeah. I am of the firm belief if it
was a real concern they would take your phone off you or as
I've recently learnt existed, they'd put them in Faraday bags,
which are a thing. Yeah.
I don't know if you know enough to comment on the airplane if I.
(11:54):
Like remember vaguely reading about it a long time ago and I
kind of I'm of the same frame ofmind.
I suspect that if you're like really up close to the cockpit,
maybe it might have, there's a possibility of some
interference. But usually with the stuff, you
know, we've got very narrow welldefined wavelength ranges that
our technology operates at. And you know, like you said,
(12:17):
unless it was an extreme risk, Ithink they would take our phones
off as if it was an extreme risk.
I think they would. But I mean, I generally just
don't use it and I'm never near the front of the plane.
So I think it's just a habit. I'm not convinced that it's
going to cause a plane to fall out of the air.
But could it interfere? Maybe, You know, if the
wavelengths overlap, if the wavelengths in, you know, our
(12:39):
broadcast spectrum of our phone and whatever all of the
electronics in the cockpit, if they overlap, then, yeah,
there's a possibility they will interfere.
Yeah, I just keep it off. Absolutely.
Look, at the end of the day, if you don't know enough, don't
bugger around with the rules because it's a plane.
Air on the side of caution. Yeah, I.
Think that's a good rule when a plane in general really.
Definitely. Continuing on with the plane
(13:01):
theme, can a plane toilet suck your innards out?
I don't know what the what the myth is here, but apparently
this is the thing people are concerned about.
It's being sucked into the toilet or being like
disemboweled. Yeah, I don't want to.
That's a horrible scene in what are those Final Destination
Horrible, horrible scene where aman is disembowel by a swimming
pool pump. Oh God.
You know, is there something else I have to fresh about?
(13:21):
I would say no, you don't need to worry about this.
And I think the reason that you don't have to worry about it is
that the only way there's any sort of risk, and it's a very
minor risk even at this, would be if you managed to create a
perfect seal with your buttocks on the toilet seat, right?
You can't do that. The toilet seats have a gap in
them on a plane, probably for that reason.
(13:43):
Oh yeah, no disembowelling. Yeah.
So I think that's not going to happen.
I've never again, there's no reports of it ever happening
ever. They've.
Covered it up, You see the same 5G.
And yeah, I'm sorry, I should stop mocking people.
That's terrible. That's all part of this
conspiracy. But no, I think basically that's
never going to happen. So you have to get a perfect
seal with your buttocks and thenwhen the vacuum is turned on, it
(14:06):
might suck some of your skin a bit further in, maybe, but it's
not going to be powerful enough to to disembowel your.
And also by the way, by the way,an airplane toilet, the stuff
that goes down the toilet is stored.
It is not ejected out of the plane, which is another myth
that you see sometimes that people think, yeah, yeah, no,
that doesn't happen. So I think you're safe.
(14:28):
I. Didn't know people thought that
was a thing. That whole just dropping it, I
just don't see countries allowing that to just be dropped
to Willy nilly. But OK, so it's not.
And if so, if you were sucked into the toilet slightly, it
would be maybe by a couple of millimetres.
But it's only if you can get this perfect seal in place.
Yeah, which you can't. Yeah, no, OK.
(14:48):
Thankfully I can take that off. The don't have to be worried
about list being in a car in a storm.
You always assume because I havedriven through the most
spectacular lightning storm and it's slightly unnerving because
you know, electricity is especially my great uncle was
hit by lightning twice. Oh.
My God. He survived.
I know. Honestly, I thought this was ABS
family myth, but it is actually true.
(15:09):
It's kind of goodness. Yeah.
But in a big electrical storm, other than being beautiful, you,
you. It's unnerving.
We all feel a little bit safer because of the tires, I think.
Is that a reality or are we lesssafe?
You are safe in a car in a storm, but not because of the
tires. It's because your car acts as a
Faraday cage. So assuming your car is a metal
(15:30):
cage is a metal chassis, then what will happen is if lightning
does strike your vehicle, which you know the risk of.
That is already pretty small, but if it does strike your
vehicle, the lightning will takethe easiest path and that's
through a metal. So all of the charges will stay
on the outside of the car and make their way to the ground.
So it's not to do with the tiresat all.
Where things get a bit complicated is if you have like
(15:52):
a a convertible car which doesn't have a metal roof, for
example, arguably that it definitely will not be acting as
a Faraday cage because it needs to have a clear path, like it
needs to have a continuous path of the metal.
So, you know, maybe you're less safe in a convertible car, even
with the roof up in a lightning storm.
But yeah, it's all about the metal, really.
(16:13):
It's all about the chassis and not really about the tires at
all. You know, that makes sense to
actually thinking about it. Yeah, electricity is a weird
thing. You know, we have this
relationship with this, and it'salso kind of a bit terrifying
and mysterious. So I understand the thing about
thinking that because rubber is an insulator on some level that
maybe that protects you. But actually what you want is
(16:35):
for the electricity to flow justnot through you.
You want the electricity to flowsomewhere else.
And thankfully in a metal car, that is exactly what it'll do.
So you're pretty? Safe in it, Yeah.
OK, so even though you've got that rubber instead of what?
Yeah, you think the actual rubber itself and the charge
leaps to ground, Yeah. Usually because you're really,
it's such a short distance, you know, So, yeah.
(16:55):
All right, OK. And lightning is negatively
charged clouds positively charged, Earth I.
Believe so. Yeah.
Yeah. And there is somewhere, and I've
forgotten where it is in the world, that gets almost all year
round. It has something like 200
lightning strikes an hour for something about 250 days a year.
And I can't remember where it is, but it.
Must be like rainforest. Yeah, I would think.
It's certainly a tropical environment.
(17:15):
I probably should have found outwhere that was.
Yeah, very cool. If I dropped a coin from the Sky
Tower in Auckland, would I slicethrough somebody?
This is another Final Destination thing actually.
I think the answer to this is no.
Now I've kind of gone around thehouses on this, partly because
aerodynamics is, is quite complicated.
You know, I was like, oh, I'll just do like a quick calculation
(17:36):
just to see, you know? Oh, you did.
OK, Oh, maths. Oh yeah.
Well, you know, if I have numbers, I will try and do a
calculation, but I think the answer is no.
But I think once you start getting bigger, heavier objects
than say a coin, then the risk becomes much greater.
So when you drop something from a building, it's moving through
(17:57):
the air as it's moving at a constant acceleration.
So it's moving at the speed of gravity, which means that its
speed is increasing at a constant rate, which is a a
weird thing sometimes for peopleto get their head around.
It is moving through the air. So it's bashing through air
molecules. It's not moving through a
vacuum. So you end up reaching what's
called a terminal velocity, which is where the air
(18:18):
resistance. So the the drag that's caused by
moving through the air, trying to push the air molecules out of
the way. That kind of balances with the
gravitational force on the coin,right?
So the speed of the coin moving through the air.
Now where it gets complicated islike you've got these things
called drag coefficients. So this tells you how easily or
how difficult it is for a shape of an object to move through air
(18:42):
or water. So there's a reason that like
planes are the shape they are because that minimizes what we
call the drag coefficient. A big ball, for example, will
risk experience a lot more drag than a sleek airplane.
And a coin is funny because a coin kind of is thin, small, it
will flip over I would expect asit's falling.
So it's actually quite difficultto calculate what it's drag
(19:03):
coefficient is. So This is why I'm kind of going
around the houses a bit. But basically from what I can
figure out, you've got like a 1 cent coin in New Zealand weighs
about two grams, $1.00 coin weighs about 8g.
They're very small. You know, they're like 10s of
millimeters in diameter. They're thin.
So I think that even when they're moving fast, I don't
(19:25):
think they're going to, they're definitely not going to slice
through you. Am I hurt a bit if it hits you
like, but I don't think it's going to like injure you.
But yeah, when stuff gets biggerand heavier, then the speed that
it reaches, the energy it has when it hits the ground is, is
much higher. So then it gets quite risky.
But I did look up because I wanted to see, I'm sure I knew
that someone would have done this calculation about
(19:46):
hailstones, right? Because hailstones are a thing
that we're obsessed with. And a hailstone with a radius of
about 5 centimeters, so a 10 centimeter diameter.
So a big hailstone would have like a terminal velocity of
close to 50 kilometers an hour so that, you know it would hurt
you, but it's not going to slicethrough you.
And that's a relatively easy thing to calculate because it's
(20:07):
a ball, it's a sphere. But Even so, things like.
Humidity will make a difference to how objects move through air,
so it's really difficult to giggly, but I think it's
definitely not going to slice through.
It might hurt you a bit. If it hits you, unfortunately
you have just now ruined the latest Final Destination movie.
Really. Because the precursor is a bit
of a coin. Because I was assumed there'd be
(20:27):
a bit of sort of path of least resistance that it would fall
through. Because obviously flipping over
at one point, you'd have more force.
I do not like talking about thiswhen I had no idea what I'm
talking about. To you.
This is quite stressful. But I just assumed it would be
easier for it to fall that way. Yeah.
And therefore it would gain a bit more speed.
Obviously not. It tends to flip, yeah.
It tends to move around a bit, and you'll have objects like a
(20:47):
dart, for example. Like a dart will tend to fall in
One Direction. It will point straight down at
the ground. But that's again because of what
we call its drag coefficient. It's got this narrow long body,
so it will fall on that like least resistance kind of path.
But we just don't have any like preference to the way that
things tumble, especially like if we accelerate something, if
(21:08):
we like launch something, it will usually stay in its
position because we've given it energy and it will hold that
position. But when you're dropping
something, you're just kind of like hands off and it will
tumble and it will move and it will be buffeted by the air if
there's any breeze or wind. Like all of those things can
interfere with how an object falls.
Would it be different in a vacuum?
Yeah, it would definitely be. If it fell through a vacuum, it
(21:29):
would probably kill you. Yeah.
Oh. OK, OK, OK.
The last question is really weird, and I think it actually
comes from a Simpsons joke. You know how toast always lands
buttered side down? Yeah.
Yeah. And cats always land legs up,
down, standing up. So what happens, the age-old
joke, if you glue a piece of buttered toast to a cat?
Yeah. Does it infinitely rotate?
Exactly. That's exactly what it does in
(21:51):
terms of physics. Yeah, I can confirm.
If only, why do cats always landon their feet?
I think just because they think quicker than us, I don't really
know, Like I think they have a asense of where their body is.
There's a thing called proprioception, which was not
something that I'd ever heard about until quite recently,
which is like a sense of where your body is in space.
So like really good athletes, for example, it's.
(22:13):
Very important and we don't train it, but we should.
No, not at all. And like very good athletes have
incredibly good proprioception. They know where their limbs are
and and where everything is. And you know, you'll see this
like I'm a big rugby fan, You'llsee this like in a rugby match
where you've got someone at the bottom of a of a mole and
they've managed to somehow know where the try line is.
Like even though their body, they've been flipped over and
(22:35):
stumbled to the ground, but theyknow where the line is.
And I think like with cats, I kind of just have AI get a sense
does not based on physics that they have incredibly good
proprioceptions so they can see where the floor is or know where
the floor is and they can rotatetheir body to meet it.
Toast of course, does not have any proprioception because it's
not. I think the buttered side down
(22:55):
thing I think is just because ofthe height of most tables.
Yes, it's all about what 1.3 is 1.5 it's just a number of
rotations I. Think yeah, maybe we should do
some experiments with like dropping it from higher heights.
Please make sure you you film those because I think it would
be quite funny, particularly to clean up afterwards.
It's super annoying. If you stick it on to the back
of a cat, then obviously what will happen is that the butter
(23:15):
side toast will want to hit the ground, The cat will want to hit
the ground also. So they kind of infinitely just
cycle and become a perpetual motion machine, yeah.
Yeah, well, we've solved the energy crisis.
Done. Congratulations.
You probably get your doctorate written very easily from 9:00 PM
the night before, I think. Yeah, super.
So just jot this down. Look, I have heard of all sorts
of absolutely insane things online that people vehemently
(23:38):
believe. Perpetual motion cat toast
machine is not the weirdest. It could be worse.
The other day I was trying to explain to someone why a water
powered engine or a water powered car won't work.
Yeah, and I understand that if you run electricity, you split
water and then you can burn the hydrogen and the oxygen is
there. You try and tell people, but
splitting water actually uses more energy than is released.
(23:59):
Yes. And people are like, oh, but you
just use electricity to split the water.
OK, so the electricity comes from.
No, I haven't convinced anybody of my argument at.
All no. But it's hard.
And I think anything to do with energy is hard because I think
we don't teach it well. Maybe I don't know.
And I think also people want simple answers.
And the reality is that few things are simple, most things
(24:22):
are complicated. And that's why you need experts
who are working on these challenges rather than randoms
reckoning that they have an idea.
And it's not to discourage people having ideas.
Like ideas. Ideas are great.
But science is about testing ideas.
So yeah, the ones that work stick around.
The other ones don't. Exactly.
Do you have a cat? I don't have a dog though.
(24:43):
OK, Dogs unfortunately don't land on their feet, so if you're
going to test that one, I'm going to need you to get a cat.
Yeah. I'll go in next door.
They have a cat, yeah. Perfect.
Yeah, make sure you film that experiment because that will be
really interesting to watch. You stick some toast to a cat I.
Think we'll just like, wrap it around its waist?
Maybe they look a little belt like a saddle.
So the toast is like a saddle. It would be lovely.
(25:05):
Oh God, you can tell it's Friday.
We've gone completely crazy. Well, do you have any other
random myths do you want to bust?
No, I don't think so. I mean, like, the world is full
of interesting myths. I'll tell you like a random cool
thing that I came across when I was writing sticky.
This is about plants. So I thought that maybe it's a
bit physics adjacent, but there's a plant called the
(25:26):
Salvinia Fern. It's actually like a horribly
invasive weed. It grows like crazy on
waterways, It chokes up waterways.
It's awful stuff. However, from a physics point of
view, it's really interesting because it has the leaves of
these ferns are covered in thesestructures and they kind of look
a bit like a whisk, like a baking whisk.
So like a long stem and then a kind of a four strips joining it
(25:48):
together at the top. So like a bubble whisk.
And these plants are really interesting because they float
on the water and they don't get wet, right?
So you could submerge this Fernan water for literal years
and you pull it out of the waterand it will be bone dry.
So it is water repellent. But a few years ago, scientists
kind of finally figured out how this particular plant is so
(26:09):
water repellent. And it's because these whisk
structures, they're covered in amaterial, a kind of a waxy
material that stops water from sticking to the leaf.
But the genius bit is at the very tip of the whisk, there's a
tiny little section that is actually water attracting.
So it's hydrophilic, that's whatwe call it in physics terms.
So it's attracting the water at the tip, but all the rest of the
(26:32):
leaf, all the rest of the structures are repelling the
water. So what that means is when you
put it into the water, air surrounds the leaf, but then
water gets pinned onto the very top of each one of these tiny
structures, these whisk structures.
So the water actually gets pinned, and it traps this layer
of air inside the Fern. So when you lift it out of the
water, it's only that tiny, tinytip that ever had water touching
(26:55):
it, ever had water kind of stuckto it.
And the scientists who discovered this are trying to
use it to basically develop coatings for boats so that you
could potentially have a boat that doesn't get wet.
So you have a boat that doesn't move through the water.
Yes, you have no fowling. It would help with speed.
Yep, It would definitely help with speed because you're moving
(27:18):
through the air rather than water.
So that's the goal. And this is what they're trying
to do. They're trying to make a coating
based on the same structure, this idea that, like, you stick
tiny bits of water, but you mostly repel water.
If you can do that on a coating,yeah, you can have a boat that,
like you said, doesn't fell, doesn't get actually wet.
It kind of floats, moves on a pocket of air and therefore uses
(27:39):
less fuel. So that would be super cool.
I'd love to see something come out of that.
Yeah. Also, as soon as you said it, I
thought that would resolve a lotof problems with packaging.
The reason we use plastic, of course, is because of so much of
our food or cosmetics or whatever contains water, so
cardboard and stuff doesn't work.
It was depending on a few things, if you could use
something like that as a coatingon the inside of a box or a
(28:00):
tube. Can we hurry this along to the
commercial? Yeah, let's have a chat.
Let's see if we can just fix it.Yeah, the weekend.
We've got the whole weekend, so two whole days.
And what do you want, really? Honestly.
So that water, is it also at allrelated to surface tension?
Yeah. So like water has quite a high
surface tension, so it kind of like it's not a skin, but it
behaves as if the layer that's touching something is stuck to
(28:24):
it. It's because it's got basically
the water molecules want to stick together really strongly.
So yeah, the surface tension does make a difference.
I don't actually know. I would love to see if anyone's
done the experiment rods in withwater, then with like something
like an alcohol, which will havea different surface tension.
Really interesting to see whether liquids like that would
wet this leaf rather than stay on the top of the leaf.
(28:47):
Yeah. So if the surface tension is
important, but I actually I don't know what it would mean in
this instance. Yeah, I think spiders are great.
I do really like them, but I really don't want them on me.
Fair enough. Freak me out a little bit.
Yeah, but I was. I'm cleaning out sort of the
pole. Well, I wasn't.
I was standing away in the corner going Oh my God, because
there was a massive spider walking along the bottom of it.
(29:07):
Oh God. And I did a bit of research
about spiders and even if they don't seem hairy, they often
trap. They can trap air around
themselves, but from surface tension and they can survive for
quite a while, which is really, really cool and also horrifying.
Yeah, it's true. I kind of feel like that
sometimes about the natural world and I think that's part of
in general, like why I feel veryill equipped sometimes to move
(29:28):
through the world because anything that's like alive.
The squishy things. Yeah, the squishy alive things,
I don't know, they're like magicor something.
Ultimately, though, because. I remember having a very
vociferous debate with an engineering flatmate, he said.
Ultimately everything is physics.
Yeah, it was very physics versusbiology.
I had an argument with a friend at university.
I mean, we're still friends, so it's fine, but she would say
(29:51):
like, because she's, well, just.And she would say, I just don't
know how you could, like, walk around in the world not
understanding how your body works.
And my incredibly arrogant response, as always.
Well, I don't know how you move through the universe without
understanding how it works, which I can.
I say I would never say that now.
I do not believe that, but yeah.It is almost like a the least
(30:12):
you know, the more arrogant you are about a little bit, you
know, right. That means to realise that oh
shit, you know nothing and you are an imbecile in the face of
everything. Did you say that astronomers saw
or it's not live? Obviously, it's just when it
gets to us. This or the formation of a
planet. No.
Yeah. So I only read the heading
because then I lost it and I can't find it again.
Yeah, they've got the the vision, the beginnings of a
(30:33):
planet, man. Yeah.
I don't know how they know because I imagine it takes eons
to form a planet I. Would think so, but how cool
that we have the ability to see things that far away and.
That long ago. Long ago, exactly.
We're getting into relativity. No, no, too confusing.
My brain will melt. Yeah, not for a Friday.
Well, there you go, there's yourweekly physics myth busting.
(30:55):
You can feel better about 5G's and airplane toilets.
Although to be honest, it wasn'tthe sucking thing that worried
me about plane toilets. It's the level of ick, yeah, and
I don't understand why there is always water on the floor.
I also feel convinced it's not water.
So. I'd like someone to explain to
me the physics of that. I don't want you to.
Please don't. I will tell you that the toilets
don't use water on a plane, so it's not from the toilet.
(31:16):
Also, it's definitely not water.It could be from the sink,
right? It's probably water from the
sink, that's sure. Sure it is.
Yeah. Yeah.
OK. We'll go with that.
Thank you again. Always fascinating, always a
pleasure. That has been your weekly
physics moment. Had a blast, thanks so much
friend. And there you go, I hope you
learned something and realise that being green isn't about
(31:38):
everything in your pantry matching with those silly glass
jars or living in a commune. If that's your jam, fabulous.
But sustainability at its part is just using what you need.
If you enjoyed this episode, please don't keep it to yourself
and feel free to drop me a rating and hit the subscribe
button Kyoda and I'll see you next week.
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