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in all caps. Join

0:48

the conversation. You're

0:51

with Cape Talk. My name is

0:53

Dan Quarter in for Clarence

0:56

Ford, but Clarence here

0:58

or not... Dr.

1:17

Chris Smith, how difficult it is

1:19

for parents to try to explain

1:21

what it means that there is

1:23

a naked scientist on the radio

1:26

on the way to school. Like

1:28

you really, like I'm the eldest

1:30

of five and it's an intergenerational

1:32

dad. What is that me? Is his

1:34

nudity somehow contributing to his

1:37

scientific process? Is clothing some

1:39

kind of inhibitor? We know that

1:41

the Eureka moment happened naked in the

1:43

bath. Is it part of his system?

1:46

Is that how he's at Cambridge? Is

1:48

that how I get a road scholarship?

1:50

Please explain to us what is happening

1:53

here? Yes, as we're following in the

1:55

footsteps of Archimedes, as you say, the

1:57

first Eureka Streika as he was doing.

2:00

Very good morning, Dan. Nice to talk

2:02

to you from, I think Chicago is

2:04

supposed to be the windy city, but

2:06

today it's Cambridge. My goodness. We've recorded

2:08

a Guinness World record wind speed, not

2:10

here, but actually off the coast of

2:12

Ireland. They got 114 miles an hour,

2:14

which is a record for our climbs.

2:16

just today because of the arrival of

2:18

a big storm. So very, very windy,

2:21

very, very cold, but you're warming things

2:23

up for me this morning. Nice to

2:25

talk to you. I'm doing my absolute

2:27

best. I'm very good at doing that

2:29

because I know that Port Elizabeth of

2:31

Kreberga now, as it is rightfully called,

2:33

is called the Windy City in South

2:35

Africa, but it's actually called, is called

2:37

the Windy City in South Africa, but

2:39

it's actually in South Africa, but it's

2:42

called the Windy City in South Africa,

2:44

but it's City in South Africa, but

2:46

it's actually. get on to the what's

2:48

up line and let us know right

2:50

now. I've been encouraged by the lovely

2:52

Amy Ray producing for Clarence Ford's shows

2:54

to ask the first question from myself

2:56

and to the naked scientist I'm going

2:58

to take this opportunity to ask you

3:01

one of my favorite stories from early

3:03

scientific research that I still don't fully

3:05

get. How did it, whether it were

3:07

the Egyptians or people in that area

3:09

of the world many thousands of years

3:12

ago, a handful of thousands of

3:14

years ago? How did they put,

3:16

as far as I understand, sticks in

3:18

the ground and use some shadow to

3:20

figure out that the world was round?

3:23

How does that even happen? Me today

3:25

with my NSC pass, which was fairly

3:27

decent, good enough to get into UCT,

3:30

would never be able to, with all

3:32

the technology that I have, get to

3:34

that I have, get to that. and

3:37

maths. I think you're referring to the

3:39

story of Eratosthenes, who was the philosopher

3:41

who did the experiment, and by chance

3:43

where he was in North Africa,

3:46

someone had dug a well and

3:48

someone noticed that at midday, the

3:50

sun shone straight down this well. So

3:52

he knew the sun had to be

3:55

dead overhead at that point. He then

3:57

measured a distance away from the point

3:59

where... the well was and stuck a

4:01

stick in the ground and got the

4:03

shadow from the stick. Now if you

4:05

draw a circle on a piece of

4:07

paper of representing the earth and a

4:09

notional line representing the well which must

4:12

be the path of the sunlight at

4:14

midday down towards the centre of the

4:16

earth, then you go a distance around

4:18

the circumference of the circle. and put

4:20

another line, which is where the stick

4:22

is, and pretend you've got a shadow

4:24

there. There's going to be a shadow

4:26

that's at a different angle, because the

4:28

stick is not with the sun directly

4:30

overhead, it's at a distance away. If

4:32

you trace that line down to the

4:34

center of the earth, you find they

4:36

will meet at the center, obviously, but

4:39

there's going to be an offset, which

4:41

is the difference around the circumference that

4:43

the stick is. what the size of

4:45

your segment is effectively, and that tells

4:47

you, if you know what that size

4:49

is, you can work at what the

4:51

rest of the circle must be, and

4:53

he was able to therefore work out

4:55

the radius of the earth, and therefore

4:57

its circumference from standard geometry. It's amazing.

4:59

He got it nearly right, and given

5:01

he was working so in such early

5:03

times with such primitive data and such

5:06

primitive instruments, it's absolutely amazing. And there

5:08

have been other giants who've done things

5:10

like this. There's an astronomer called Roma.

5:12

who was watching some of the moons

5:14

of Jupiter and watched one of those

5:16

come flying into view and then disappear,

5:18

flying into view, he was able to

5:20

work out the actual distance to Jupiter

5:22

based on the time it was taking

5:24

the light to get to us from

5:26

this moon appearing and disappearing when it

5:28

should be appearing. They knew what the

5:30

orbit was. there was a difference in

5:33

time and he worked out the reason

5:35

is that sometimes Jupiter is on the

5:37

same side of the solar system as

5:39

the earth and sometimes it's on the

5:41

far side and that difference in the

5:43

arrival time of the moon compared to

5:45

when it should have been appearing was

5:47

the time it took the light to

5:49

travel across our solar system so he

5:51

could calculate the speed of light. It's

5:53

amazing and it was nearly right. Right,

5:55

that's how good the naked scientist is.

5:57

Let us know your questions. Anything under

6:00

the sun, even if the sun is

6:02

being used to work out that the

6:04

flat earth is wrong. I want to

6:06

ask you, Dr. Chris, if you get

6:08

questions a lot about skin care routines,

6:10

because you are the naked scientist, we've

6:12

actually got a few this morning, I

6:14

think a lot of people think about

6:16

the skin care routine they would have

6:18

if they didn't wear clothes. So from

6:20

Anne, there's a question which says, Prince

6:22

Anne because I've done it not for

6:24

any nefarious reasons or to stop the

6:27

police identifying me but just because I

6:29

was in a swimming pool and I

6:31

noticed that there was some green patches

6:33

on the bottom of the pool so

6:35

I thought I'll scrub those off and

6:37

it was at the bottom of the

6:39

deep end so I sort of weighed

6:41

myself down a bit and didn't have

6:43

a scrubbing brush I just used my

6:45

hand because it seemed to be doing

6:47

quite a good job but when I

6:49

surfaced I found that I had removed

6:51

most of the finger print patterns from

6:54

my right fingers and I couldn't unlock

6:56

my phone. and I didn't have a

6:58

code, I had to use the fingerprint

7:00

thing, so I couldn't get my phone

7:02

for a week. It was great for

7:04

my social media, social media distancing that

7:06

I did that week. You can do

7:08

that, but the thing is, the skin

7:10

is an amazing organ, it's our biggest

7:12

organ, and if you're a rhino, your

7:14

skin weighs about a quarter of a

7:16

ton, just your skin. It's an amazing

7:18

thing, but the skin is an amazing

7:21

organ, it's our own being coming through

7:23

the window, and it's... lighting up and

7:25

you can see the sunbeams, all these

7:27

particles, you are walking through not just

7:29

you, but also all the people you

7:31

live with. So you are breathing in

7:33

all the people, past and present actually,

7:35

and over a lifetime it adds up

7:37

to kilograms of dead people that we're

7:39

living in. And the microbial world know

7:41

this and so we are festooned with

7:43

bacteria that are very good at eating

7:45

that stuff. So skin is turning over

7:48

a ferocious rate. And this means that

7:50

even though you may rub bits of

7:52

it off. It replaces itself incredibly fast

7:54

and it's very responsive and... So if

7:56

you have an area of skin that

7:58

becomes damaged, it knows it's been damaged

8:00

or it's been eroded, and it augments

8:02

the activity of a population of stem

8:04

cells that live below the skin, because

8:06

the top layer of skin, that's all

8:08

dead. The skin cells are flat, dead,

8:10

and dried out and just stuck together

8:12

like a harsh, a hard leathery layer,

8:15

deeper down in the skin. That's where

8:17

the living cells are, stem cells that

8:19

make new skin, and they can wind

8:21

up and wind down their activity according

8:23

to how much skin you need to

8:25

make. So yes, you can exfoliate yourself

8:27

to the point where you've removed a

8:29

lot of skin, but you will grow

8:31

it back, thank goodness. Okay, so if

8:33

anybody was thinking of committing crimes and

8:35

removing their fingerprint tracing, it's not effective

8:37

whether or not you use it. You'd

8:39

have to damage the stem cells right

8:42

deep down to stop the skin regenerating

8:44

if you wanted to do that. No

8:46

more advice for criminals. Thank you very

8:48

much. We're on Cape Talk on a

8:50

Friday. This is the naked scientist. My

8:52

name is Dan Corda in for Clarence

8:54

Ford. We have a voice note from

8:56

Lois for the naked scientist. Hi naked

8:58

scientist. So we have a dragon fruit.

9:00

It's planted in a pot. the roof

9:02

of our deck which has a beam

9:04

running across it. And all the other

9:06

dragon fruits in the garden they go

9:09

like their normal way but this dragon

9:11

fruit has shut straight up all on

9:13

its own without any support and it's

9:15

gone straight towards the beam. What I

9:17

want to know is how does it

9:19

know, because you know it's a it's

9:21

a plant that needs to attach itself

9:23

to something and then like creep and

9:25

hang over, how does it know the

9:27

beam is there? And how does it

9:29

know to grow straight up and find

9:31

the beam because it doesn't have eyes

9:33

and it doesn't have a brain? Over

9:36

to you, Dr. Chris. Thanks, Lois. Now

9:38

plants, you said they don't have eyes,

9:40

but they do have ears, remember, boom

9:42

boom. If you go to a plant

9:44

that feel full of corn or corn

9:46

or barley, there, there, there, there, they

9:48

can hear, I'm just joking. Prince Charles

9:50

used to famously talk to his plants

9:52

and people have actually done studies to

9:54

see if plants are sensitive to sounds

9:56

and the results are not... compelling. Someone

9:58

also I interviewed once had done the

10:00

experiment where they were trying to train

10:03

plants so that they'd have a plant

10:05

with a fan blowing over it and

10:07

a plant without a fan blowing over

10:09

it and they gave it various inducements

10:11

to see if it would respond to

10:13

and learn that under certain circumstances it

10:15

should grow a certain way and that

10:17

didn't work compellingly either. But plants definitely

10:19

do what they do very well. They

10:21

grow roots down, shoots upwards, and shoots

10:23

towards the light. So they actually can

10:25

see in inverted commerce and they can

10:27

feel gravity. and we know this because

10:30

plants have actually been grown in space

10:32

where they grow in a very

10:34

extraordinary weird way and I actually

10:36

interviewed somebody from NASA called Volkakur

10:38

and this is about 20 years

10:40

ago when the if you remember

10:42

the Columbia space shuttle unfortunately had

10:44

an accident and it disintegrated when

10:46

it was trying to return to

10:48

Earth and aboard that spacecraft were

10:50

some experiments and some survived and

10:52

they recovered some of the things

10:54

and one of them was an

10:56

experiment to grow moss in space

10:58

and this helped the scientists to

11:00

discover that plant cells have inside

11:03

the cells a structure called the

11:05

cytoskeleton and there are particles of

11:07

starch bobbing about inside the cell

11:09

and they... land under gravity on

11:12

this cytoskeleton, deform it, and this

11:14

gives the plant an idea, almost like

11:16

a spirit level, of which ways up

11:18

and which ways down. So plants do

11:20

actually tell up from down because they

11:23

have these pressure sensors inside the plant,

11:25

not that dissimilar actually to a system

11:27

that works in our own ears, that

11:29

helps us to tell whether we're going

11:32

up or down or sideways. So that

11:34

guides certain parts of the plant to

11:36

grown a certain way, roots know where

11:39

down is. because they can follow that

11:41

signal, shoots nowhere up is because they

11:43

follow the reverse of that signal. And

11:45

then there are other drivers, plants are

11:48

obviously very sensitive to light, and they

11:50

have a phototropism. And when light

11:52

shines on one part of a

11:54

plant, it induces the production or

11:57

in other cases suppresses the production

11:59

of other... growth signals. and this

12:01

has the effect of steering the

12:03

growth by laying down more cells

12:06

on one side of the stem than

12:08

the other side, and this pushes the

12:10

plant to grow in a certain direction.

12:12

And this is why you turn the

12:15

pot plant around on the window seal,

12:17

because otherwise it will curve towards the

12:19

light. Now, you're a drag-plant around on

12:21

the window-sill, because otherwise it will curve

12:24

towards the light. Now, you're dragonfoot, you

12:26

don't see what the sort of anatomy.

12:28

I'm going to go up, because inevitably...

12:31

light comes from the sky I'm going

12:33

to go upwards I'm most likely to

12:35

get more light up there. The naked

12:37

scientist we've got a text in

12:40

from Yan that I find very

12:42

interesting hi doctor Chris and Dan

12:44

wild and domestic cats over years

12:46

have looked at patterns and stripes

12:48

on their skins all directions or

12:51

none the tails as stripes are

12:53

always around and never along the

12:55

tail can you explain that? Probably

12:57

because and I don't know the

12:59

answer to this I mean cat

13:02

patterning is really interesting and it's

13:04

both mathematically very interesting but also

13:06

genetically how it happens and biochemically

13:08

how those patterns form is very

13:10

interesting and people have spent a

13:12

long time studying this. The tail

13:14

is a sequence of segments down

13:17

the body and if you look at the

13:19

anatomy of the tail it's a sequence of

13:21

bones which have then grown out as an

13:23

extension of the spinal vertical column and

13:25

we just don't have one but some

13:27

animals do and they have bones a

13:29

bit like the bones in our back

13:31

all the way down the length of

13:33

the tail. Now if you look at

13:35

a developing creature, look at a developing

13:37

human for example as an embryo we

13:39

develop as a series of segments

13:42

and from the head to the tail end

13:44

there are these things you could draw stripes

13:46

across us. and along those segments the reason

13:48

the body knows where to put things during

13:50

development and things in different parts of the

13:53

body develop in different ways like for example

13:55

where your breasts are you have that segment

13:57

forms nipple tissue that is under a different

13:59

set of genetic instructions than hormones which

14:02

is why men and women both have

14:04

nipples. So all the way down the

14:06

body it knows where it is down

14:08

the body and it's following a specific

14:11

genetic set of instructions that correspond to

14:13

that segment of the body. So I

14:15

suspect that there's something about the patterning

14:17

coding that knows what segment it's in

14:19

and also has the same manifestation that

14:21

gives cats their interesting stripy patterns elsewhere

14:23

on their body and bring those two

14:26

things together and you get that. that

14:28

pattern and it's going to be a

14:30

ring around the tail because the tissue

14:32

forms initially as a blob which rolls

14:34

up at like a tube so you think you

14:36

start as a sheet and you roll it

14:38

around so the front meets the back a

14:40

bit like if I had a toilet roll

14:42

that's how the tissue forms it's a bit

14:44

like if you you cut the toilet roll

14:46

along one side you can I'm rolling it

14:48

to make a flat piece of paper. You

14:50

can roll the edges back together. That's how

14:52

the body forms. It forms a tube by

14:54

rolling up. And that's why you're going to

14:57

ring all around the tail. So I'm speculating.

14:59

I'll take it away and have another think

15:01

about it, but I think it's going to

15:03

be somewhere along the lines of what

15:05

I just said. Okay. Then we got

15:07

another one in from Chris. I know

15:10

we don't have a lot of time

15:12

left, and I want to get as

15:14

many people's messages. because there are so

15:16

many myths and I'm what I personally

15:19

am tired of turning upside down and

15:21

trying to drink glass of water and

15:23

washing my face against my will. The

15:25

posh medical word is singultus for a

15:28

cup and I think the world record-breaking

15:30

bout of hiccups lasted something like 75

15:32

years or something like that as

15:34

an American gentleman. No man. Where

15:36

did the hiccups start? How long

15:39

did he live? Well it was

15:41

little obviously and it did not

15:43

respond to any of the normal

15:45

mechanisms including getting a fright, turning

15:47

upside down, etc. Sometimes hiccups can

15:49

be caused by certain drugs. Usually

15:51

they're a diaphomatic spasm of your

15:53

frenic nerve which originates from the

15:55

top part of your spinal cord,

15:58

but is controlled by nerve centers. in

16:00

your brain stem, which is the top

16:02

of the spinal cord that connects your

16:04

spinal cord onto your brain proper. And

16:06

there are lots of collections of nerve

16:08

cells there that do important tasks that

16:10

we don't have to worry about. And

16:13

there are pattern generators there that create

16:15

the respiratory rhythm. And obviously we can

16:17

surmount that and voluntarily breathe in and

16:19

breathe out. That's how we talk and

16:21

sing, for example. But it means that

16:23

when you go to sleep, you don't

16:26

have to worry about breathing. but because

16:28

those nerve centers that do that control

16:30

are very close to other regions that

16:32

process things like excitement, arousal, fear, when

16:34

certain things wind up those other nerve

16:36

centers, the activity in those centers can

16:38

spill over into the respiratory areas, causing

16:41

these diaphromatic spasms down the frenic nerve,

16:43

so you pull your diaphragm down, all

16:45

of a sudden, drawing air in, and

16:47

if your vocal chords are together... noise.

16:49

I see. Okay, that's so interesting. Then

16:51

we got a voice note from Sharon.

16:54

A lot of us are suffering this

16:56

very personally right now. The mosquitoes are

16:58

out and about and taking names. Let's

17:00

see. Get Sharon on the radio. Good

17:02

morning, Chris. My question is, can Mosquito

17:04

see when you're looking at them? You

17:07

know, when you have that single mosquito

17:09

that's bothering you? And every time you

17:11

look away and then it's back at

17:13

you, but if you look at it.

17:15

It will never come. It doesn't matter

17:17

how long you wait for it. It

17:19

knows. It knows. Yeah, that's a great

17:22

one. Thanks, Sharon. Well, mosquitoes can see.

17:24

They do see, but they are far

17:26

better. at finding you using other detectors.

17:28

They have antennae which are festooned with

17:30

chemical receptors that can smell a raft

17:32

of different chemicals and those are our

17:35

breath and the carbon dioxide. We exude

17:37

other volatile chemicals coming off our skin

17:39

and they can also sense heat. So

17:41

they home in on us using all

17:43

of those mechanisms to find us, but

17:45

it's likely because they know that they're

17:48

very volatile. when they're feeding and it's

17:50

only the female ones that do this

17:52

and they do it when they're going

17:54

to make eggs because they need the

17:56

protein in blood but they know they're

17:58

at their most vulnerable when they're feeding

18:00

because you could splat them. So they

18:03

are very sensitized to any kind of

18:05

stimulus that says you might be onto

18:07

them. So when your breath pattern changes,

18:09

when you swing around to look at

18:11

them, you're going to move your body,

18:13

you're going to move the air around,

18:16

you're going to breathe at them, and

18:18

all of these things may change the

18:20

airflow and that kind of thing, and

18:22

they're sensitive to that, and they may

18:24

well take alarm and disappear or change

18:26

their trajectory, and that way they try

18:28

and avoid you... getting onto them, but

18:31

you're quite right, they are the most

18:33

irritating thing and especially at night when

18:35

they seem to know where your ears

18:37

are above all other structures on your

18:39

body. The thing that always makes me

18:41

panic is the very simple thought and

18:44

it's a... It's an intrusive thought that

18:46

I had, and I just realized I've

18:48

never vocalized to anybody, is I'm just

18:50

scared that one day the mosquitoes will

18:52

have a meeting and go, hey guys,

18:54

you know, if we just walk, instead

18:57

of flying, they won't know that we're

18:59

coming. We will have such a good

19:01

time. I just need the Muzzi's not

19:03

to decide to walk. That would be

19:05

great. Naked Scientists returns next week, Friday

19:07

with Karen's Ford on Views and News

19:09

and News of News and News and

19:12

News from 9. Dr. Hey

19:16

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operations. operations. a a finance

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HR Rockstar with Workday. workday