Instant Genius - The Science Focus team: What's inside November's issue?

Episode Date: November 2, 2020

In this episode of the Science Focus Podcast we chat through the November 2020 issue of the magazine, which is on sale now. Editor Dan Bennett explains why, this month, we’re focusing on food myths. Scientist and writer Professor Tim Spector penned our cover feature to reveal the fact and the fiction surrounding diet and nutrition, and some of his research may have results that surprise you. Talking about the amazing variety of our ocean’s other-worldly sea slugs is managing editor Alice Lipscombe-Southwell. These small marine animals might sport cute faces and bright colours, but they’re armed with an array of deadly defences too. Commissioning editor Jason Goodyer digs into our piece about algorithms, which asks, what went wrong with the A Level results algorithm? And online assistant Sara Rigby scrutinises the stats around plug-in hybrid cars to find out if they’re as eco-friendly as marketed. Let us know what you think of the episode with a review or a comment wherever you listen to your podcasts. Subscribe to the Science Focus Podcast on these services: Acast, iTunes, Stitcher, RSS, Overcast Listen to more episodes of the Science Focus Podcast: Matt Parker, Helen Arney and Steve Mould: What links coffee, snowflakes and frogs? Andrew Hunter Murray and Dan Schreiber: Is there really no such thing as a fish? Matt Parker: What happens when maths goes horribly, horribly wrong? Helen Russell: What does it mean to be happy? Robin Ince: What's inside the mind of a comedian? Dara Ó Briain: Can you find the fun in science? Ryan North: How do you invent everything? Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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Visit name audio.com to learn more. You're listening to the Science Focus podcast from the BBC Science Focus magazine team, with the UK's best-selling science and technology monthly, available in print and in several digital formats throughout the world. Find out more at ScienceFocus.com or look out for us in your app store. Hello and welcome to the Science Focus podcast. I'm Sarah Rigby, online assistant at BBC Science Focus magazine. With me today, I have editor Dan Bennett. Hi. Managing editor Alice Lipscomb Southwell.

Hello. and commissioning editor Jason Goodyear. Hiya. We're going to tell you all about the November issue of the magazine, which is on sale now. So first up, we've got Dan who's going to tell us about our cover feature. Yeah, so this month we decided to focus on food myths. And the reason for that is essentially we have one of our sort of regular contributors.

It's a guy called Tim Spectre. And you might know him recently. He's appeared in the news. as a result of his COVID tracker, COVID symptom tracker app. And he launched that recently to try and get a handle on some of the sort of the wide-ranging symptoms that people were experiencing at the start of the pandemic.

But before that, he was particularly interested in food and diet and particularly the thing that we all noticed that, you know, you can basically have one friend who eats a ton of food and is lucky enough to remain incredibly skinny and another who just has a normal diet. I'm going to say that's me and ends up being a bit overweight. And so he over sort of the course of a couple decades studied this. And in particular he looked at twin studies where he would get pairs of twins, feed them the exact same diet, or feed them different diets, and find out how that affected their weight loss or gain.

And what he observed was there were significant differences, even when you gave them the same number of calories, the same amount of fat, carbohydrates, proteins, etc., he found that these twins were putting on different amounts of weight. And what he could put that down to, he thinks, is the microbiome. This is the kind of colony of bugs and bacteria that live in and on you, and in particular, in your gut.

So what it seems to be the case is that these bugs were essentially affecting individuals the way they were processing carbohydrates or calories or proteins. And then there were other factors like, you know, did they have high metabolisms where their genetics, sort of driving a really hungry metabolism, which could affect how you lose or gain weight. So in the end, he basically has recently published this new book called SpoonFed. And in it, he kind of sums up his sort of, I think, you know,

many decades of research into this area and breaks it down to all the sort of food myths that we all encounter on a day-to-day basis. I mean, the most famous one probably is that breakfast is the most important meal of the day. And so in it, we got him and we got him to share his sort of favourite, or I suppose, most persistent food myths and got to sort of bust them piece by piece. So I'll share with you sort of my two favourite, my two favourite pieces. One was that calories, which is sort of a bit of a pet topic of my mind, but calorie counting doesn't work. Now, we've all heard, you know, men are supposed to have two and a half thousand calories a day, and women should consume 2,000. And as long as you eat less than that, you shouldn't put on any weight.

And if you eat more than that, then you're going to get fatter. But the more you dig into this idea of calories and where they come from and how we burn them, the more you sort of find out it's actually pretty crazy. So for instance, our metabolic rate, which I talked about earlier, which is how quickly we burn these calories. So how quickly we turn the sort of sugars, proteins and fats and stuff we put it on to our body into energy can vary by 25% between people. So that means I could, you know, comfortably get through 2,000 calories. Not much effort.

But another person sat next to me can eat the same amount and still put it on weight. But it gets sort of deeper than that. If you look at where the calorie sort of first started life, it was actually in the 19th century when this idea sort of first came about. And it shocked me to find out when I was researching this, that we still use many of the calorie measurements back from the 1900s today. So when you see a ready meal and it says, you know, it contains 437 calories,

some of the times, and obviously it varies from countries and countries, they're just saying, okay, well, there's 30 grams of potato in here, and Atwell, who was the scientist originally came up, his original measurement for how many calories a gram of potato has was, you know, 30 calories, so times it by this weight, and therefore this is how many calories it has. Which is crazy, because not only, obviously do we know a lot more about food now and how it breaks down, but it doesn't take into account so much.

For instance, a cold potato contains less calories or fewer calories than a hot potato. So when we account for how many calories and something, we're essentially saying that everything inside it can equate to a calorie. So if you, I mean, a basically simple way of putting, if you set fire to this potato, how much energy does it produce? And in the case of potato, if you've got a lot of starch and carbohydrates, these are kind of complex molecules. And as they cool down, they become essentially stronger and more harder to break down bonds in these molecules.

And so therefore, your body has a harder time getting and unpacking the sugar from that potato. Whereas if you have a hot potato that's more cooked, you know, and you can tell the difference in the taste, right? A hot potato tastes sweeter than a cold potato. definitely don't eat raw potatoes, by the way. That's very dangerous. But the raw potato essentially just has much less calories in it. And so it tastes sort of more bitter and less sweet. So what was this out well guy?

What was his method? Was he just like getting different food stuff and setting it on fire and seeing, I don't know, how much it heated up water was? And how did he determine it? So, yeah, he had a couple of experiments. So his first experiment was essentially what was called a bomb calorometer. So, yeah, the idea was you put something in a chamber, you burn it, you can bust it. It's probably more accurate with something, you know, quite an intense explosion.

And you see how much it heats the water in this chamber. So sorry, I'll put that another way. So you get your food in a chamber and you surround. it with a big chamber of water. And as you burn the food, you measure how much the temperature surrounding that food goes up in temperature. But he also did some other quite interesting stuff where he fed people the average American diet of the time. Which, and I'm going to quote some of my notes here, which I read somewhere was molasses cookies, barley meal and chicken gizzard. Wow.

Yum. And he fed that to a group of students over like the course of two weeks. And they would eat, sleep and exercise inside this chamber. And so he would, and then he was measuring how much they would heat up that chamber to get a sense of, you know, what they were burning. Because obviously the human body burns some of the calories and some of it comes out as waste. But it goes on further and further. The more you look into the calorie kind of idea, the less it makes sense that we're kind of slavishly following what's on these packets and then

ignoring everything else, like how many B vitamins are in it, what kind of protein content is there. And actually, when you think about people's individual differences, it actually starts look at a wildly sort of inappropriate way to determine what you eat. And I'll just leave you with one fact, which is I think when this was sort of first adopted in the US, I think in the, I think it was say the late 60s, I want to say, when it became past that, you know, everything you sold had to have a caloric labeling on it.

What went after that was the steepest growth, in obesity since record began. Because people started solely focusing on calories and ignoring everything else. Dan, you promised us two food myths. What was the second one? Oh, yeah. So the other is my favourite.

Didn't make it into the mag. So if you want to know more about calories, definitely pick up a coffee. And that is that coffee is good for you, which I kind of suspected, because obviously I drink a lot of it. But I was kind of surprised because you think of coffee, you think of heart palpitations when you have too much,

you think of stress and, you know, getting wired. But actually they found that in some broad studies of kind of American and Japanese populations, that drinking sort of this, So this also surprised me. Moderate coffee drinking, which equals three to four cups a day, which seems like a lot to me. Reduces your chance of death, or your risk of death.

I suppose it's always a risk of death, but reduces your sort of risk of death by 8% and heart disease by 20%. I remember I read a study in Italy and there was saying like something like having five espressoes a day, would really drop your chances of getting liver disease. Oh, really? So we don't know why. We don't know what it is that's doing it. And it may not even be the caffeine. So coffee is full of antioxidants, but particularly something called a chemical called a polyphenol, which Tim sort of suggests could be beneficial because the polyphenols are feeding the microbes in our gut. So it all sorts of comes roundabout back to this idea that, you know, as well as our own digestive system, there's loads of little creatures inside us that are digesting the things we eat. And genuinely speaking, if you can look after them, then you'll be in good health.

But also, I think, you know, the piece really establish is something that I think is really important now, because we will read a lot of food science in our jobs. And we see that the information changes, you know, almost on a weekly basis. And I think it can be a bit, you know, how do I figure out what I should eat? If I can't count calories, what can I do? If I can't, if I can have eggs one day and then the next day they're bound for me,

and then again, they're good for me, what should I do? And Tim had a really good, sort of, has a good answer to this in his book. which is we need to start sort of ignoring the scientists I obviously shouldn't say here I'm not sure that's something we want to be advertising as a science magazine he says in his own book he says don't listen to scientists which from a scientist obviously surprised me

I think we should clarify only when it comes to diet Yeah. So what he advocates for is listening to your own body. There's so much difference. We're not there yet where we're not at the point where we're able to, I mean, we're pretty close, but, you know, look at your poo and decide exactly what you should and shouldn't be eating. That's down the line, I think.

But in the meantime, we need to kind of, you know, skip breakfast, see what happens. Eat a big carbby heavy meal, see how you feel afterwards. If you feel fine, then, you know, don't believe the hype that, you know, carbs are going to slow you down. Equally, if you do feel tired and you do feel kind of uncomfortable after eating a big, kind of, you know, steak and mashed potatoes, then that's telling you that your body digest that in a certain way. And so he advocates, you know, obviously do read about science, please, but your body, biggest kind of helper is your own, your own senses and your own body.

All right, Dan, thank you very much. Some of our listeners might have heard of some of this before because Tim Spectre did a live event for us. He hosted the very first BBC Science Focused live event. And we've got more of those coming up. So please watch out for them. And now Alice is going to tell us about sea slugs. Hello, so yeah, in this issue, we've got a great article by one of our marine biology

she writes as Helen Scales. Now she talks about sea slugs or nudibranx in this issue, and they're one of my favourite marine animals because they're so cool. I mean, they're just really brightly coloured. They've got really interesting biology. And yes, you can sort of find out all about them in the issue. I think probably my personal favourite that she features in there is something called the leaf sheep.

Now this sort of has to be seen to be believed. it looks like almost a teeny tiny little sheep. But it's a sea slug. And it's even got like a little face by the looks of it, so it looks like this little sheep. And it's quite interesting because it grazes on algae. Now those algae that it eats, it'll harvest the chloroplasts from there.

So then if ever it gets to the point where there's not enough food for the leaf sheep to eat, then it can just use the energy from the chloroplasts and it can still survive. So that's pretty clever. So it can photosynthesize. like a plant? Yes. Wow. Wow. Yeah, it's almost just like harvested those chloroplasts and it'll just like let them

photosynthesize within it so it can get the sugars from there to keep it alive. But it's tiny. I think it's only about sort of five centimetres long, you know, it's a little tidily thing. Yeah, it's very cool. So the little, the little leaf sheep that calls around, And the process that it does, the nicking the chloroplasts, it's pretty unique, isn't it? It's not really found elsewhere in the natural kingdom, is it? Yeah, there's a few examples of it, but there's not many animals that do that sort of thing. But within the sea slows, again, they're quite interesting because, as well as nicking chloroplasts, that's one really cool thing. but then there's some species

and they'll actually feed on venomous animals and they'll sort of steal those sort of venomous cells and they'll use those within their body then as a defence mechanism. Wow. It's completely outwitting the animal's defence mechanism. I know, I'm going to take that from you. I'm going to take that from you.

Yeah, there's one, it didn't make it into the magazine but it's called the Blue Sea Dragon. Now this one lives out in the open ocean. It's quite cool. It sort of floats upside down on the surface of the water and just surface tension is just sort of holding it there. And it's got all these blue tendrils coming off it. It's really cool.

Now, this one will sort of living out in the open ocean. You don't really get it on coastlines unless it dies and washes up. But that will feed on Portuguese Manawar. Like, yeah. So they're like the Manor war like super venomous. You know, if you end up getting attacked by one of them, it's really painful and you can die. That's bad. But this little tiny nudibranch, it will just sort of feed on it.

It'll harvest all those little venomous cells from the man of war, stick them into its own tendrils. So if anything then brushes up against it or attacks it, it can just sting them. No way. Yeah, what's really good is it, because it harvests so many of these stinging cells. It actually almost becomes more venomous than the man of war, so it's like even worse. Yeah, that one was really good.

And I said, they're so beautiful these animals as well. They're just, yeah, they look like little dragons almost. It just floats around in the sea. I was looking at some of these sea slugs the other day, and I found out about one called the bunny sea slug and it is the cutest little thing you've ever seen. It's just like, if you just imagine like someone's drawn a cartoon bunny and then stopped before they've put on the legs or the foot.

So it's just a little tiny little ball of fluff, like a little cylindrical ball of white fluff with black spots over it. And it even has two little ears. Like, I don't know what they're for. I was only looking at pictures. Just our amusement. Yeah, it's a cute. thing, yeah.

They do, they all that sort of, leastly, like they belong in an enneedible kind of animation. But they are... They're like Totoro.

Yeah, they do. But they are kind of... They're quite hard to find, don't they, Alice? I mean, they are quite hard to find. They are found all around the world. You even get them, you know, on coral reefs, you'll get them on beaches in the UK.

They'll be in sort of the Arctic, Antarctic, deep seas. There are a lot of species of them. I think there's more than thousand species, so there are a lot of them. But it's one of those, because they're so well camouflaged a lot of time, you have to really look for them. Now, the one species you can get in the UK that I really like. I mean, we've got about 100 species in the UK, but I really like the sea lemon, so-called, it looks just like a lemon. It's sort of, you know, about 10, 12

centimetres long, it's all sort of warty and yellow and knobbly. And you can find that if you go to a beach, you look down on the low shore, have a little poke around in the seaweed, lift some rocks up. and you might find it there. And I remember from reading this, do they sort of taste the water through something on their head so their tongues effectively like on their face? Yeah, I mean like Sarah was saying earlier,

the little bunny ears, they're like rhinopause and they'll sort of, they're on their head and they'll use that to sort of detect things and taste the water. And if they're sort of a forked shape as well, they can then sort of detect in what direction any smells are coming from. Oh, so quite similar to like a snake's tent. Yeah, a little like that.

So, Alice, the most important question, can I keep one as a pet? Probably not. I mean, if you were an incredibly good marine keeper, then maybe, but these are marine animals. So you need to have good salt levels. You've got to have nice clean water for them, lots of water changes,

and you need to have corals and seaweed and things like that for them to feed on. so probably a bit hard to keep us a pet. But you might find one at the beach and you can just hold it, you're like, oh, you're really... Not one of the venomous ones, though. Yeah, maybe...

Yeah, so I should probably just get a regular bunny rather than a bunny sea slug. Irregular bunny or a garden slug. Yeah, you can't get those African land snails, don't you? People have those as pets, the enormous landstains. Yeah, and you get people like in them crawl on over their face because the snail gel's meant to be good for you, isn't it? something and you think, yeah, maybe not.

One cool thing about my sea lemon again because I'm slightly obsessed with them is they belong to a certain group of sea slugs that their gills are actually around their anus. So you've got their anus and they've got these like frilly gills around it. And if you see them under the water, you can almost see those really well. They're really feathery. So, yeah, essentially it's breathing right from around its bum, which is lovely. All right. much Alice and now Jason is going to tell us about algorithms. Yeah so following on from the

sort of debacle that happened with the A-level results over the summer with the Offquell algorithm. We got Tamanda Harkness who's written a lot about this sort of thing in big data to have a dig into what exactly went wrong with the A-level results and the algorithm. So just for a bit of background, basically, Offquil got commissioned by the government to make an algorithm that predicted and assigned A-level results to students. But when the results came through, 40% of students got grades lower than they were predicted by their teachers. So in some cases, it was quite severe. They'd go down from getting an A down to a C or something like this. So obviously, they were pretty miffed about this.

But once you look into it more, you saw that there was also a big disparity between the results awarded to state students and private students. And there was also, like, you're more sort of rarer, perhaps subjects that are less popular amongst the lower class students such as classics and law. They also had slightly inflated grades. So obviously there was something going on. This didn't work. And in the end, they ended up having to just say, sorry, this didn't work. We'll just go back to using the grades that the teachers predicted.

But after all this, Boris Johnson came out and said, it was the fault of a mutant algorithm he called, I think it was the phrase that he used. But of course, the algorithm didn't just suddenly develop, consciousness and go rogue. It was programmed by professionals. And that's sort of the crux of the idea of Tamandra's piece, that algorithms are just algorithms,

and they do what they're programmed to do. So it really kind of, for me, I think, algorithms are obviously, we know they're everywhere, kind of making lots of decisions from us, from simple things like your car insurance. to your mortgage rate, etc. So it kind of thrust this idea that algorithms might not be so fair,

in a very human sense, they might not seem fair, into light. And so it wasn't, so in the case of the off-call thing, they were, it sort of materialised that it just essentially, it was doing a fairly accurate job, but it ignored sort of outstanding students in bad schools. They were one of the big victims, right? Yeah. So it really sort of highlights one of the big downfalls

with the way that we currently use and program algorithms. And they're great for predicting wider trends, you know, like traffic flows, or even you can use them for detecting abnormalities and medical scans. in fact they outperform even trained human doctors. But when it comes down to the individual level, they can make really serious errors like they did in this case with the students from working class backgrounds or from less well-performing schools generally,

getting severely penalised for those larger general trends. And they're quite good. You mentioned the medicine. I remember we reported on this might have been last year where you can feed patient records into a machine learning algorithm which is another type an algorithm where effectively the computer decides its own set of rules and parameters and they're better than doctors aren't they at predicting what you're going to get

yeah and it's sort of is that's really interesting because it's one of those things no one really knows why. It's just like they work, but exactly how they're working and why the performance are well, it still remains a little bit unclear. But there's another, this, I don't know if you've heard,

there's like this pred poll future crime predicting algorithm that was in the news of why. That's a really good name. They were using, some states in America were using it to predict future outbreaks of crime. But it basically got skewed

towards ethnic minorities and people from lower, the same story, right, people from lower socioeconomic backgrounds. So a lot of the authorities that were using are actually scrapped it. So how is that supposed to work? How are they supposed to be able to predict, you know, individual events based on... Yeah, see, that's where it falls down a little bit, right, because it's just certain areas, certain times,

certain scenarios that they fed in based. That's like one thing that Tamandra says about the algorithm's her piece is that you basically, you can only use data from the past. So that's, you know, there's no room for maneuver in that sense, and that it's just only past, of course, that's how they work. But that's part of the kind of inmate. She had a good example. didn't she, where, you know, you can say that, say, you know, most murderers are men,

but it doesn't mean that most men are murderers. You can't just pick around and go on the street and say, well, you're probably a murderer, so the algorithm says, off you go. Yeah, she said nine out of ten murderers are male, which is, that's, yes. I mean, I was quite surprised with that. But yeah, then she's like, well, you know, that's our piece of information. but it's all about context, right? How do you use that piece of information?

If you want to use it in something like one of these future crime predicting or criminal profiling. It's a big issue, isn't it? Because especially in the medical cases, we have to sort of trust them. And that's a big problem. So we know that these algorithms are really good at identifying, okay, this patient, just based on their records,

are likely to have this kind of cancer. We don't know necessarily because it's a machine learning algorithm and that means that it has come to that conclusion based on its own set of parameters and rules. We're not entirely sure how it comes to that conclusion, but we just know that it's 30% better at doing that than a doctor. And if we don't find a way to trust them, then we can't actually benefit from that knowledge.

So with this algorithm, is there actually where we can improve them Or is it just the way they're built it's probably always going to be wrong? Yeah. I mean, well, that's a really good question. But, I mean, there are some. So basically, how this one worked, the off-core one worked is they kind of averaged out schools' results for the last three years, you know, nationally and then by school. And then they got the students within the individual schools.

graded, you know, from who's the best, who's the worst at this particular subject. And then just sort of used that to divvy up all of the grades. So you could have been in a situation where you were in perhaps a poor performing school. You were the second best student, you know, say you got A stars for everything. But because previously the performance was much lower, your grade would have been adjusted down for that reason. So it's, I don't know how they would make something like this work. It's like Tremandra says in a piece. It sort of really falls down when, well, I don't know what you're taking, 10 GCSEs per student. So in order to get the fine detail of something like that accurate, I think

would really be a tall order. Okay, thank you very much, Jason. And now last up, I'm going to tell you about plug-in hybrids. So in September, there was a report that was released by the campaign group Transport and Environment, and they said that plug-in hybrid electric vehicles actually emit, on average, more than two and a half times as much carbon dioxide as official test values claimed. The original lab tests claimed that plug-in hybrids emitted 44 grams of carbon dioxide per kilometre. But transport and environment, they studied 20,000 vehicles in real-world conditions. So they took the fuel efficiency data from 20,000 plug-in vehicles just being driven around in the world. And they found that on average, the carbon emissions are actually around 100,000.

17 grams of carbon dioxide per kilometer. So that works out at about 2.6 times more than the official values. Now, a self-charging hybrid would emit about 135 grams of carbon dioxide per kilometer. And an average internal combustion engine car would emit about 165 grams of carbon dioxide per kilometer, so not actually that much more. So if someone bought their vehicle, based on these, the lab test values, they would be expecting to save, you know, over 100 grams of carbon dioxide per kilometre. But in reality, it's only about 50. So that's, you know, they're like immediately halving the amount of carbon dioxide that they're saving. So the different, so just a, so the different car types, if someone's not familiar. So we've got the plug-in hybrid. And so that is,

is and correct me if I'm wrong. So that's, we're talking about the type of car that has a battery and electric motor that you can go to, you know, the service station and plug in and charge up. And then what's now sort of becoming called the self-charging, that's one that you can't plug in. But, you know, like a, say, a Toyota Prius, you drive around and the regenerative, things like redenative braking kind of harvest energy and charge the the battery backup. And so their study was saying that the plug-in ones, the ones that have these sort of 30-mile range batteries,

they were the ones that sort of the chief offenders, were they? Yeah, that's right, Dan. So you're supposed to be able to drive about, up to about 20 miles, I think, on zero-emission mode. So that's just using the battery motor, not using your, engine at all. But this report by transport and environment actually found that in many cases, you can't use the zero emission mode at all. So they have some quite surprising examples of various different models of car. They found things like if it was too cold outside, it would have automatically switched to the engine or if you had your rear wind screen heater on, it would switch to the engine mode or, yeah, things like that. So, you know,

if you have too many, like, devices on at the same time, it'll switch to your engine mode. So what that means is people who, you know, should be able to do their commute, for example, you know, low speeds, short distances, entirely on zero emission mode, couldn't actually use it at all. So that is one quite big reason why these emissions are so much higher than expected. But another one that surprised me a bit more actually was that apparently they believe that most people who own these don't actually charge them up. They just use the engine. Yes, that seems a bit weird to me. Like, why would you buy an environmentally friendly car and then not use it?

So I spoke to Dr. Ian Walker. He is an environmental psychologist at the University of Bath. And I asked him this question. And he said, well, the first thing we need to ask is, are people actually buying plug-in hybrids because they care about the environment? his team have done some research into car buying and people's priorities when they're buying cars. And he says that a lot of people do say when they're buying a car, environmental considerations are a concern for them. But they actually found that it's quite low down in the list.

So he calls it a tertiary consideration. So you've found your price range. You've found the type of car that, you know, it does everything you need. It has, you know, boot space or whatever else. else that you need. And then once you get down your final few, then people will say, well, which one's more environmentally friendly? So people are actually, in general, less concerned with environmental considerations than they say they are. But a second factor, which actually probably contributed quite a bit was that the government offer a grant to buy a plug-in hybrid car.

So you can get up to, I think it's £3,000 off the cost of a plug-in hybrid car. But as he points out, no one actually checks if you're using it right. So you can just get this car for cheaper and drive it as a petrol car instead. And they're probably quite future-proof when it comes to cities. starting to sort of consider what cars can, can't enter their limits down to pollution. So because if they're if they're on paper doing this, you know, their pollutants are at this level, then they're probably fine. But like I say, in reality, it's probably two or three times that they get away. Yeah. Yeah, that's right. I have to admit, I thought they were quite a quite good idea

when they first came about because you've had a lot of what we call without naming E Brands Chelsea Tractor type cars you know those big four by fours that you see on the school run more than anywhere which might be an unfair characterization but they're in the city centres you know the biggest

thing they have to scale is the curb spewing out loads of pollution and CO2. And I thought, oh, well, actually, if these models have that, then maybe for that 30-mile trip, they could just turn off on the electric battery. It's pretty surprising that they just ignore that and roll around. Well, it might be that in certain lab situations,

you can get it to work, but it sounds like it's pretty tightly controlled in lab tests. So it's probably in real life. You know, if you're going to test driver plug-in hybrid, try and make sure that you can actually get it to run on zero emission mode before you buy it. Yeah, I mean, I expected the real world performance to be different from the lab performance. But I've got to know, I'm pretty shocked that if you turn on the heated rear window, then you can no longer use the motor.

That seems crazy to me. So Dr. Ian Walker was, I was asking him whether or not he thinks that, you know, we should, it's worth buying these plug-in hybrids, given that they're getting on for almost as polluting as, you know, self-charging hybrids or even internal combustion engines. And he, well, he didn't really answer my question. What he said instead was that he thinks we're looking at this the wrong way.

He thinks that people often get caught up in the argument of, should I get a battery, a battery electric vehicle, should I get a hybrid, you know, what should I do? when he thinks that the questions we should be asking are more like, why do we all need a car? Do we all need a car? And how can we change our lifestyle so that we don't all need a car? So who here has a car?

Do any of you have a car? No. Bicycle. No, not anymore. I have a city car club outside my apartment that I use. but actually I have to admit I am kind of looking for a car at the moment and one of the

so this is what I sort of think you can surely do a lot when you look at, because I'm looking at these things like what are the pollutants just because I admit it's probably not primary consent but it is sort of something I think I think about

and it just generally seems much better if you just get an old second-hand car that was headed towards being recycled and dumped and all of the pollutants that come with that, get a bit of life out of that and then move on. And yeah, I think we're quite fortunate to be based in Bristol, which is very easy to kind of get around by bicycle and things like that. But if I was in London, well, I wouldn't get a car anyway for London,

but for the rest of the country, it's not quite so easy, is it? And it's interesting that you bring up getting around in Bristol because one thing that I think about Bristol is that the public transport is not laid out well at all. And I think that is actually a big hindrance. And part of the reason why so many people around here have cars, Bristol actually is massively exceeding air pollution limits. And I think part of that is based on the way that the public transport is laid out.

And if you look at a map of the bus routes going through Bristol, it's laid out sort of like a bicycle wheel. So you have the city centre in the middle and then spokes of all the bus routes going out, outwards. And what that means is, if you want to go from one side of the city to the other, you have to go through the centre. So there's no routes going around.

So if you want to get from one side of the other, it takes forever. Because, you know, this city centre is obviously going to be the busiest part. and it's much, much faster to go around the outside. So if you're living on one side of Bristol and you work on the other side of Bristol, are you going to sit on a bus for an hour and a half, or will you just get a car and do it in 25 minutes?

And I think that's actually probably a big problem that it is stopping a lot of people from moving from cars to public transport. Personally, I think the way forwards is that public transport all around the country needs completely revamped. We need to be pushing people towards public transport if we really want to reduce our carbon emissions. And one example of that is that if I want to go and visit my parent house, I have to get two buses and then a train and then a tube and then another train and then a bus on the other end as well. And I mean, it's fine. It works. But I mean, if you've got loads of bags and the last train, the cheapest train is, you know, gets you in a

at 11 p.m. and it, you know, it costs you 100 pounds. Then you start to think, well, what if I just got a car and just drove it? It'll cost me much less. It'll take me the same amount of time, if not less, because it won't be standing around on platforms. I can take as much baggage as I want. I can take people with me. So yeah, I think that we really need to be just completely revamping the public transport system. So people don't just go, well, what if I just get the car. Yeah, I suppose that's, that's one of the issues with these, these sort of studies and these conversation pieces is it puts the on sort of individual responsibility of the buyers and the owners when actually there's a much bigger picture that's often missed out that means that these individuals

can't, you know, they don't have options to take public transport when the public transport isn't serving them. So actually there's a much bigger piece of sort of transport development. that needs to be really, really done if we're going to actually, you know, make a dent on these targets. So thank you very much for listening to this episode of the Science Focus podcast. The November issue of BBC Science Focus magazine is out now. Also in this issue, we look into long COVID. Michael Mosley explains how to manage seasonal effective disorder, and our panel of experts answer your questions.

Thank you for listening to the Science Focus podcast from the BBC Science Focus magazine team. with the UK's best-selling science and technology monthly, available in print and in several digital formats throughout the world. Find out more at sciencefocus.com or look out for us in your app store. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name audio believes you can have digital precision with analogue warmth. Alongside French acoustic specialist focal, name creates high-end audio systems combining innovation with craftsmanship so you can listen to music, just as the artist intended. Discover more at name audio.com.

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