14:01

and so plants and animals, rabbits, when do they

14:03

breed? I mean, like what happens in the equator?

14:05

Okay, so the whole concept of seasons that we

14:07

have here in Australia comes from the United Kingdom

14:10

and because they were our colonial masters

14:13

and so they have the summer, winter,

14:15

autumn, spring. And we're on

14:17

the other side of the equator but a

14:19

much different land mass and

14:21

surrounded by a lot of ocean. And depending

14:23

on where you are in Australia, the

14:26

locals had, pretty before the westerners came

14:28

along, six or eight different

14:30

seasons and they were related not so

14:32

much to this artificial spring summer but

14:34

rather when food was available and that

14:37

was related to food in the ocean,

14:39

was related to plants,

14:41

related to animals on land. But

14:44

then when you get near the equator, it

14:46

tends to, I hesitate to use the word

14:48

simplify but I will, it simplifies into two

14:50

seasons, the wet and the dry. Either

14:53

it's really dry or it's just pouring like

14:56

crazy. I mean, the northern

14:58

hemisphere in, Easter

15:00

is when the rabbits breed, that's why we

15:02

have the Easter eggs and all that sort

15:04

of stuff. In the southern hemisphere, Easter is

15:06

not in spring, so it doesn't make sense.

15:08

We're having, in my opinion, having rabbits and

15:10

Easter eggs in

15:13

March, April when we have Easter. You're

15:15

totally right, yeah. The whole thing's irrational

15:17

and it's sort of run by cultural

15:19

heritage. So then what

15:21

happens with plants and animals on the equator?

15:23

Do they, when do rabbits know when to

15:25

breed? When do plants know to start new

15:27

life? That's interesting.

15:29

So I was reading about the locusts underground and

15:31

how do they count the seasons to know to

15:34

come up after 11 or 17 years. So

15:37

they're alive underground and they get a

15:39

flux of glucose from the tree and

15:42

that goes into the soil where they are. And

15:44

we don't know, we know that they're counting these

15:46

fluxes that last for a couple of months but

15:49

we don't know where they're counting it. They don't like

15:51

to have a board where they count on. And then

15:53

if you're talking about plants breeding, there'd be just so

15:55

many different plants doing different things at times of year.

15:58

We need a botanist for this. I'm out of my range of depth. You've

16:00

given me something I need to do more homework on.

16:02

They surely adapts. They surely, that's just probably how it

16:05

is. Well, they've been there for many years. And so

16:08

you would get certain numbers of crops. Like I know

16:10

that if you're growing climbing beans, you can grow them

16:12

at this time of year, but not others. I don't

16:14

know what happens at the equator because I haven't been

16:16

there long enough. Thanks, John. I don't know. Thank you,

16:18

John. I'll figure it out. Thank you. We'll

16:20

work on this. We've got Indigo from Clyde.

16:23

Indigo, what's your question? Hey,

16:26

but first I just have a

16:28

question about treks after having a

16:31

really big, distal cry. So

16:33

a big cry is at 11 o'clock the other

16:35

morning, if something happens. And then

16:37

I still had a huge, huge killer headache all

16:39

through that night and feeling so bad in the

16:42

next morning. Is it due to

16:44

stress or something happened in the brain? I'm

16:46

just curious. So Indigo's talking about, you know,

16:48

when you just have that big cry, you

16:50

let it all out. And then, you know,

16:52

your puffy eyes, the rest of it, but

16:55

then you've just got that searing headache that

16:57

just kind of hangs around. Sure.

16:59

What's that? Now, can I ask you, Indigo, do you

17:01

have a tendency to migraines anyway? I

17:04

used to, but that stopped. Okay, so the

17:06

good thing is that it stopped, but you've

17:08

still got that genetically there hidden in the

17:10

background somewhere. So let's just run through them.

17:13

Firstly, when you're crying, there's a lot of

17:15

muscle tension involved, and you might not feel

17:17

it, but the muscles are tensed in your

17:19

head and your neck and your shoulders. Dehydration,

17:22

micro amount. You're not gonna lose many tears

17:24

that way. Sinus pressure does

17:26

happen. So there's a bad evolutionary hangover

17:29

where the drain point of our sinuses

17:31

is not at the lowest point. If

17:33

we were on all fours, our sinuses

17:35

would drain really neatly, but instead, stuff

17:38

can build up inside them, and you

17:40

can have hormones

17:43

getting involved with laying

17:45

extra buildup of pressure because you've got more

17:47

liquid in there. I think

17:49

the main thing in your case is that you've

17:51

got this background tendency to migraine, and somehow, we

17:54

don't know the pathway, it brings it out. So

17:56

we don't fully understand microbes, because if we did,

17:58

we'd be able to say... Oh, okay, you're going

18:00

to have a migraine at quarter past 10 tomorrow

18:02

morning, and we can't do that. So,

18:04

you fit into that category of we know there's something going

18:06

on, and that gives us a partial

18:09

explanation. What do you do to

18:11

get rid of it, to deal with it? Do you

18:13

take a painkiller? Do you lie down? Do you stay

18:15

in the dark? Although,

18:17

yeah, lots of water. I had special

18:19

painkillers. I haven't taken them

18:21

for months when I get migraines anymore, but

18:24

yeah, I do. Everything they suggest

18:26

you to do, but nothing seemed to work the

18:28

other day. Well,

18:31

in you go. I hope you're okay, but also

18:33

nothing better than a good cry, letting it all

18:35

out. And a good lie down, and a slice of cake

18:37

with a bit of tea. Yes. We've

18:39

got Hamish in Border Town here. Hamish. Dr

18:41

Hamish, welcome. What's your question? G'day,

18:44

doctors. I've been getting up early for work a

18:46

lot the last month, and as a result, seen

18:48

a lot of beautiful sunrises, and

18:50

it seems like the light is different

18:52

at sunrise than it is at sunset.

18:55

And I was just wondering if there's any truth

18:57

to that. In

19:01

most societies, people

19:03

work a lot in the daytime, and there's

19:05

more air pollution in the daytime. But even

19:07

in Australia, which is really clean with regard

19:09

to air quality, and you can

19:11

still see the sun, depending on where

19:13

you are, hit the horizon, there's still

19:15

11,000 people dying every year. So

19:18

there's more particles of pollution produced by

19:20

burning stuff, so the sunrise has a

19:22

different quality from the sunset,

19:25

because the sun rise tends

19:27

to have cleaner air. On the other hand, it

19:29

all depends on where you are. So in Sydney,

19:31

you've got a triangular flow of air. And

19:35

so first thing from about midnight till

19:37

a bit after sunrise, it goes from

19:40

sort of the northwest Richmond down to

19:42

the coast. And then during the day,

19:44

it blows from the coast out to

19:46

south of Sydney called Camden, which is

19:48

this nice, beautiful country area,

19:50

and it's in a valley, and it's got

19:52

the highest pollution in Sydney, even because the

19:55

pollution from Sydney is blowing out of it.

19:57

And then during the daytime, during

19:59

the night between in, sort

20:01

of around midnight, it blows along the bottom

20:03

of the Blue Mountains. They've got this triangular

20:06

circulation. So there's that local effect on where

20:08

you are, depending on where you're seeing through

20:11

a lot of dirty air or clean air.

20:13

But it's basically the pollution caused during the

20:15

day that changes the sunrise and the sunset

20:17

on average. We are in the midst of

20:19

science with Dr. Karl and we've got Peter

20:22

from Millicent here. Now Peter, you're

20:24

watching a movie. Talk to me. What's

20:26

your question? So when watching a

20:29

movie or even a TV show, I

20:31

like to have the subtitles on. I feel like

20:34

I can hear it better, understand it better. I

20:37

don't know why. I've got friends that do

20:39

the same. I know people who absolutely hate

20:41

it on the subtitles are on all the time. But

20:43

it's just almost like a

20:45

comfort thing. I just want to know why.

20:47

Is there a reason? Or are we all

20:50

just quirky? In

20:53

movies, most of them come out of the USA or

20:56

occasionally out of England, the United Kingdom and

20:58

Europe and they're speaking differently from the way

21:00

that we speak. If they

21:02

were all in Australia, you'd automatically tune

21:04

in straight away. So having

21:06

the subtitles gives you a better understanding so

21:08

then you think that you hear it better,

21:10

which in fact you do because you know

21:13

what to expect. Often

21:15

the dialogue in movies is very fast

21:17

and clipped and you've really got

21:19

to have the subtitles on or have

21:21

watched a whole of those movies and you've tuned

21:24

yourself in. So each time

21:26

I talk, especially in Texas, I

21:28

have to talk slowly for about the

21:30

first 10 minutes so that people can

21:32

tune their ears to the different speech

21:34

and I cannot talk quickly. Yeah.

21:37

So I think that's a major factor that they're speaking in

21:40

a different language

21:42

or dialect and there's that cultural imperialism where most

21:44

of the stuff comes from not Australia and that

21:46

just helps you get over that little bump of

21:49

trying to understand it better. I was talking to some friends who

21:51

were in the US and they said that when they order a

21:54

beer, they have to order a beer for them

21:57

to, because they're like, be like, what do you mean? Yeah,

22:00

they put order of beer. Well, on

22:02

one hand, the Americans are very rotic,

22:05

which means that they emphasize the R

22:07

and with regard to the W-A-T-E-R stuff,

22:09

H2O, they chuck in

22:11

another R. It's war-der. Whereas

22:14

we Australians go anti-rotic and we

22:16

turn in the Rs into a

22:18

H-H sound. Can I have some

22:20

water? Water. Water.

22:22

There's no R. Nice. We

22:25

don't have the R and so that's why they have difficulty. When

22:27

I say my name, they say Kyle,

22:29

K-Y-L-E. Carl. Carl.

22:31

Oh, Carl. Dr. Carl. Yeah,

22:34

that's it. But it's so interesting. I understand

22:36

what Pete is saying because I watched a

22:38

movie the other day and subtitles weren't available

22:40

and it was an American movie with Katie

22:42

Holmes and Josh Duhamel and if you've ever

22:44

watched them in a movie, it is just

22:47

mumble, mumble, mumble. And I couldn't understand. At

22:49

times it felt like they were speaking another

22:51

language and it was very fast, snappy dialogue.

22:53

And it makes me concerned because then you

22:55

don't have subtitles at the cinema, you know?

22:57

So I'm like, I can't get too used

22:59

to subtitles when I'm watching movies

23:02

at home because it's not available in the public.

23:04

Is this a way to get fabulously successful where

23:06

you have an app that you have on your

23:08

phone, you have your phone running and then it

23:10

shows the subtitles and blasts them into your

23:12

brain via a neural link into

23:14

your brain? I don't know.

23:17

Oh my God, maybe we need glasses. Thanks,

23:19

Peter. Thank you, Dr. Peter. No worries. Thank

23:21

you. We've got Oscar here. Oscar, you had

23:23

a question about reception and radio waves. What's

23:25

happening in the workshop right now? Dr.

23:28

Karl, today we're working in like this garage, right?

23:30

So we've got Triple J running on the radio

23:32

and it works fine. There's zero phone reception. But

23:35

I know that radio, like phone

23:37

reception runs on radio

23:41

waves as well. But I just want

23:43

to know why it's not working. Whereas

23:45

sometimes I drive into a car park

23:47

and the radio stops working but my

23:49

phone reception is still going. Ah, okay.

23:52

Well, firstly, they are all

23:54

electromagnetic waves, but the radio tends

23:57

to run at around 100 megahertz.

24:00

that's the radio, and

24:02

so the waves are quite long. Whereas

24:04

with the phone, that tends to

24:06

run up at around three and

24:08

a half thousand megahertz, 35

24:13

times higher, so the wavelengths are shorter.

24:15

The advantage of the

24:17

longer wavelengths is that they penetrate

24:19

better. And so with the

24:21

phone networks, as we've been going from

24:23

2G to 3G to 4G, we've been

24:25

getting less and less range, but we're

24:27

getting a lot of higher data. It's

24:29

the swings and roundabouts. So as you

24:31

go to the higher frequencies, which are

24:33

in the mobile phones, they're less good

24:35

at penetrating through concrete. And

24:37

so with 5G networks, in some cities

24:40

they've got a range of maybe 400 meters,

24:42

whereas back in the old 3G, you

24:44

could hear maybe 20 kilometers away. So

24:47

the higher wavelength does not penetrate

24:49

so well through the concrete. So

24:52

it's getting better but worse? Yeah,

24:54

you get more data. If you can get something, you

24:57

get more data, you get more cycles per second, but

24:59

it can't penetrate so well. We've got Jade

25:01

in Airleigh Beach. Jade, you've got a

25:03

hypothetical what's going on? A

25:05

hypothetical? Yeah, I have a question. It was what

25:07

would happen if a comet or

25:12

asteroid, I don't know, hit

25:14

the moon and destroy it? What

25:17

would that mean for how we live our

25:19

lives like tides and things like that? What

25:22

would the difference be? Apart

25:24

from the romantic thing of looking at the

25:26

beautiful sun, the moonrise and

25:28

getting all romantic, the

25:30

tides would be two-thirds smaller in

25:33

height. So if in your local

25:35

area the difference between high and

25:37

low tide was 3 meters, suddenly

25:40

it would be 1 meter. But then that

25:43

also means that on the beach where you've

25:45

got a sloping shore, the backwash left and

25:47

right, left and right in and out would

25:49

be so much less. And the tidal zone,

25:51

they call it the intertidal zone, instead

25:54

of being maybe 40 meters across would be

25:56

10 meters across. And

25:58

so you'd have less diversity

26:01

of ocean life. So

26:03

on another thing there'd be

26:06

less likelihood, the Earth

26:08

could wobble more and it could

26:10

tilt more extremely in its orbit.

26:12

At the moment the Earth is

26:14

locked at around 23 and

26:16

a half degrees from the vertical as it goes around the Sun.

26:18

It varies between 21 and a half and 24 and a half,

26:20

but if the moon

26:23

wasn't there you could vary a lot more

26:25

and that would be bad

26:27

for the life that existed. A new form of

26:29

life would evolve but the life that had been

26:31

there before and was at a different angle would

26:33

be tend to be selected against. The

26:36

main thing is the tidal height. So a

26:38

little bit of chaos. A little bit of

26:40

chaos. I saw a movie where

26:42

I think the moon was coming within a

26:44

couple of hundred kilometres of the Earth. I

26:46

couldn't watch all of it, I had to

26:48

stop. But it looked beautiful. It did look

26:50

lovely. So close up. Yeah. Karl, we were

26:53

talking about how we often need

26:55

subtitles on movies to, I don't know,

26:57

further get in our brain what is

26:59

happening on the screen, what they're saying.

27:01

Someone saying some of the reason the

27:03

dialogue is inaudible in movies

27:05

on TV is that often it's mixed for

27:07

the cinema and big surround sound speakers and

27:09

does not translate to the small screen or

27:11

small speakers in that case. I

27:14

completely forgot. So when you've got

27:16

a proper sound system at home

27:18

you've got speakers roughly the size

27:21

of your head yet the speakers

27:23

on most TVs maybe

27:25

the size of a 20 cent coin or so

27:27

they're much smaller and they can do a lot

27:30

with that and so when you go to a

27:32

sound bar you have something the size of your

27:34

fist and they've done a lot of fancy physics

27:36

on it. So that was another factor I completely

27:39

forgot. Thank you so much. The sound system straight

27:41

out of your TV is not as good as

27:43

having it fit into a proper sound system. Which

27:45

is probably why subtitles aren't as required at the

27:48

cinema if you do have that full range

27:50

of hearing as well. Sure. Yeah we've got

27:52

Mel in Gold Coast. Dr. Mel. Mel what's

27:55

your question? Hello doctors

27:57

I'm just wondering why is it that... winter

28:00

kids just don't seem to feel cold

28:02

like adults do. My

28:05

niece and nephew running around at the football

28:07

in shorts and a t-shirt. Well, the first

28:09

factor is that they've got a higher metabolic

28:11

rate than adults and it gradually drops down

28:13

until they're teens. The second one is that

28:15

they're more active in

28:17

the world and so having

28:19

been involved with our

28:22

setting up our local baby jail at

28:25

home for the nieces and nephews, I've

28:27

decided to invent a new form of

28:29

exercise to get fabulously wealthy, I call

28:31

it baby robics as opposed to

28:33

aerobics. So instead of just walking from here

28:35

to there, I'll walk over here then I'll

28:37

jump, then I'll go to the side and

28:39

I'll do this and they find the most

28:41

complicated way to go anywhere and they're just

28:44

burning up energy like crazy. So in addition

28:46

to their natural background, higher metabolic activity, they've

28:48

also got a higher activity rate. So

28:50

just sitting quietly, they're burning

28:52

up energy faster than we are but then

28:54

secondly they're moving more than we are. And

28:56

thirdly, they tend to involve themselves more with

28:58

the world around them and so when they're

29:00

concentrating on playing, they're really playing and they're

29:02

right into it and they're not into the,

29:04

oh, I'm suddenly cold or not, they ignore

29:06

those sort of feelings. Ignore them.

29:09

Does that help well? Oh, thank you. Yeah, that's great. Okay.

29:13

Actually, I should give the name baby robics away

29:15

to anybody who wants it. Please feel free to

29:17

go ahead and set up a new way of

29:19

exercise or weight loss. Baby robics. How

29:22

do you write that one? I can't... Weight

29:24

loss in babies. Yeah. Maybe

29:27

what babies do, you'll lose weight. Hey,

29:29

we've got Grant in Sydney. Grant, what's

29:32

your question? Hey, doctors,

29:34

how's it going? Good. Well,

29:36

thank you, Dr. Grant. I had a question about corpses

29:39

and the stink that they produce. I was

29:41

wondering if, do we

29:43

perceive that as being disgusting and rotten

29:45

as a defense mechanism so that

29:47

we don't eat it, so that we don't get sick? Yeah, you've

29:50

hit the nail on the head. The

29:52

chemicals have been analysed and have been

29:55

given rather nice names such as

29:57

cadaverine, like a cadaver, or... to

34:00

test that, but that's going down

34:02

the pathway. That's quite good, but it

34:04

is correct. Like, that's why it checks humidity. And I've

34:06

got 60 plus the internal humidity. I didn't worry about

34:09

it outside in the backyard. And

34:11

the average temperature is between 18 and 23 degrees centigrade.

34:14

And the average humidity is between 63 and 75% in sight.

34:16

So, and that didn't seem to

34:20

have a major effect. Some days it was 80%. I get 80% of the of

34:22

the hob, have with the condensation

34:25

on it. And some days it'd be 100%. And

34:28

some days it'd be 50%. But there was always

34:30

something there. Okay, now look, one

34:33

last question. Do you have knobs

34:35

to operate the induction stove? Or do you

34:38

have those stupid touch controls? The touch controls,

34:40

unless your fingers clean or moist enough that

34:42

they ignore you. I am now going to

34:44

give you a 17 syllable

34:46

classic three line haiku I have written

34:48

in favour of the knob. Because

34:51

when you hit the knob, you grab the knob, you

34:53

twist your wrist and the knob turns and you know

34:55

where you are. It's gone to two o'clock or seven

34:57

o'clock. And here comes my haiku, which the family and

34:59

I wrote one night in our hate of noblas

35:03

hobs. Here we go. Though

35:06

only a knob, twist

35:08

to make cooking better, a knob

35:11

on your hob. We

35:17

wrote that between us. That's beautiful. That's beautiful.

35:19

A knob on your hob. Yeah, we need

35:22

knobs on the hob. We

35:25

got one last round of science for Dr.

35:27

Karl Questions. Sean in South Gippsland, what's yours?

35:29

Last night when I was driving home

35:32

from work would have been maybe 10

35:34

30 11. The moon was really,

35:36

really large, extremely large. And

35:40

as I drive like a kilometre or so down the

35:42

road, sort of like around a couple of bends and

35:44

come back up, then it looks like a lot smaller.

35:46

And then I drive a little bit further and I'd

35:49

come up and see come up, I've sort of like

35:51

in between some trees. And then it

35:53

was sort of big again. So I was just wondering what

35:56

the go is with that. Obviously, I'm

35:58

not travelling too far in. in comparison

36:00

to how far the moon's away to

36:02

where I am, but just those short

36:04

amounts of distance and like going around

36:06

some bends and stuff like that, its

36:08

size changed so dramatically. Okay, so firstly,

36:11

when the moon is on the horizon,

36:13

it is further away than when it's

36:15

straight above you by the radius of

36:17

the earth, about 6,000 kilometers, so

36:19

it should look smaller when it's on the

36:21

horizon, just kissing the horizon. And secondly, the

36:24

air acts in a way to shrinkify it,

36:26

not magnify it. So there are two reasons

36:28

why it should look smaller. And when you

36:30

actually measure it with the right optical instruments,

36:32

it does look smaller, yet our brain makes

36:34

it go bigger. And the straight answer is

36:36

we don't know why. There's a whole bunch

36:38

of reasons given. Sometimes you can compare us

36:40

to something like a tree, but if there's

36:42

no, it'll look bigger. But if you've got

36:44

nothing on the horizon, it still looks big

36:46

on the horizon. If you've got no trees,

36:48

it still looks big on the horizon, smaller

36:50

up above you, we don't know why is

36:52

the answer. Cameron in Perth, what's your question

36:54

about evolution? Hey, doctors,

36:57

I've got basically a two-part

36:59

question. When

37:01

was the last recorded

37:03

instance of human evolution?

37:06

And I really wanna know

37:08

what Dr. Carl's, or

37:11

what he thinks our next stage of evolution

37:13

would be. Oh, the next stage

37:15

is easy. We're just a cloud of iron

37:17

vapor weighing 50 kilograms, the diameter of a

37:19

planet floating through space on magnetic fields, read,

37:21

disturb the universe by whatever his name is,

37:23

good book. Secondly, one

37:26

very well-documented case of evolution was about 6,500 years ago

37:29

in Hungary, and

37:31

about 4,000 years ago in Africa and

37:34

in parts of the Middle East, where

37:36

adults evolved the ability to

37:38

break down lactose, which

37:40

is two sugars stuck together. And the

37:42

two sugars, when they stay stuck together in your

37:45

gut, they then cause water to come towards them,

37:47

and they give you what's charmingly called the squirts.

37:50

But then humans evolved the ability to break

37:53

those two sugars down into two individual sugars,

37:55

then they go into the body, and you

37:57

get extra nutrition from them. Two-thirds of the

37:59

world are... lactose intolerant, one third

38:02

can have a milkshake and they're not. So there's a

38:04

and there are more recent ones, but the big obvious

38:06

one. And

38:08

that's it. Thanks so much for listening to

38:11

this episode of Science with Dr. Karl. If

38:13

you want more Karl in your life, all

38:15

you've got to do is take a scroll

38:17

through the podcast feed wherever you get them.

38:19

If you're on Apple Podcasts, remember we can

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see your reviews and we really appreciate them.

38:24

Thank you so much. Hoviz John, you gave

38:26

us five stars and said, this is one

38:28

of my favourite podcasts. I've learned so much

38:30

from this podcast than going to school. Listen,

38:33

hey, hey, don't drag the

38:35

school system like that. But hey, we can work

38:37

in tandem. We can work in tandem. My name

38:39

is Lucy Smith. This episode was produced by Sarah

38:42

Harvey and we'll catch you

38:44

next week. See ya. Dave Marchese here

38:46

from the Triple J Hack Team. Hey,

38:48

if you love Dr. Karl's podcast like

38:50

I do, you might enjoy the Hack

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