Chris -   Ah, The nature and nurture debate!

This is a really hard question to answer for a number of reasons, one of which is how do we assess and appraise IQ (intelligence quotient). 

There’s a guy called Jim Flynn who was working in New Zealand, at the University of Otago, and he’s credited with noticing what’s now dubbed the “Flynn effect.”  He points out that if you look at IQ test results that go back over many, many years, the average IQ has been rising by about three IQ points every decade.  This means that if a hundred is the average IQ (an average person in a population with average IQ has an IQ of a hundred), that means that if you take off three decades worth of improvement, people would’ve been in the mentally subnormal category a few years back, which obviously, they weren’t!  He makes the point that it’s the way in which we measure IQ which has to be considered as well.  So some people just don't trust the IQ test.

But if you assume that we do, what proportion of the IQ that you or I have is because of the way our parents brought us up, and what amount is due to the genetic legacy that we inherit from those parents?

Well there’s one quite neat way of looking at this and you can probably guess what it is: to look at twins.  Nature has blessed us with a set of natural clones, identical twins, and also a set of non-identical twins which grow up usually in the same environment as each other, but they don't have the same DNA in common.  So you can compare the two and that’s exactly what researchers have done in the past. 

There’s a guy called Paul Thompson who is at UCLA in America; he published a beautiful paper in 2001 in Nature Neuroscience.  What he did was to take 40 twins - 10 identical pairs of twins and 10 non-identical pairs of twins - and carry out brain scans on them. 

They compared the fine structure of the brain in both groups of twins and they found that identical twins had 95 to 100% similarity in the fine structure of their brains.  But the non-identical twins were much less similar. 

Then you ask, "well, in that setting, how similar were their IQs?" 

When they did simple IQ tests, they found that, for the identical twins, there was a significantly stronger relationship between their IQs than there was between the non-identical twins.  So this shows that there’s something to do with the way in which the brain is wired up and connected that definitely contributes to how intelligent we feel we are or that people measure us as being.  

So, the best guess at the moment is that there is some general factor - some people dub it "G" - which is what gives you your intelligence, and this seems to have a genetic effect.  This has, superimposed on it, an environmental and nurture effect. 

So, in other words, you have a genetic legacy which is then manifest according to how nature impacts on it.  So if you have a good educational upbringing and a good genetic legacy, then you probably will fulfil your genetic potential.  That’s not to say everyone who has a very high IQ is going to fulfil their genetic educational potential because they may just not get educated.  So I think that the best guess is that it’s about 50/50.

We posed this question to James Jackson from the University of Cambridge...

Hydrocarbons are all are from dead organic material and you need an astonishing set of circumstances to make oil out of these things and preserve them.  First, you’ve got to concentrate them somewhere where they’re not dispersed or oxidised, which means in swamps, marshes, lakes or something like that.  Then you’ve got to heat them up slowly over a long, long period to cook them up to make oil.  And then, when they make oil and start to buzz off, you’ve got to have some way of trapping them. 

All these things, it turns out, happen on the margins of continents. 

If you stretch continents and try to pull them apart what happens is they "neck" - and that’s what the North Sea is. The North Sea, for example, exists because Scotland and Norway moved apart about a hundred kilometres and so the land stretched and necked; the floor of what is now the North Sea got a bit thinner and it sunk below sea-level. 

This caused it to become buried in sediment. Sediments just gets washed in, and all those dead bugs which were there got buried deeper and deeper and gently got cooked for a long time.  Eventually, the North Sea stopped stretching. Had it carried on it would have been a plate margin - we would have got the edge of the continent and Scotland would have been over by America somewhere and Norway would still be in Europe. So, the circumstances for making oil are very good on the margins of continents.  Especially the margins of oceans like the Atlantic ocean, which is not a plate boundary - there are no earthquakes there. 

Now, what happened in Saudi Arabia is that that happened to be on the margin of a huge ocean which separated Asia from the southern continents.  So, a hundred million years ago, Africa, India and Arabia were all a long way further south from where they are now and they’ve all moved north and bashed into Asia. One of those places is [what is now] Saudi Arabia, Iran and Iraq. 

So what’s happened is the margin of that ocean, with the margins of Arabia, and Africa and India, have all just popped up above sea level.  So it’s not that there is more oil there than anywhere else.  There’s loads of oil all the way over on the other continental margins but that’s underwater.  It’s hard to get out; it’s hard to find and it’s hard to suck out.  Whereas in Saudi Arabia, it’s popped up nicely above sea level and also in Iran and Iraq.  So it’s actually extremely easy to find. 

In essence, it’s more that it is conveniently situated than anything else; but, geologically, what you’re looking at is like the edge of Ireland, the western side of Ireland, which has just run into something and popped back up above sea level.

Helen -   These elephants were in a rehabilitation centre - they’ve all been rescued from logging operations, I believe, in Thailand.  They’re often used to go into the forest and drag out trees that have been felled.  These elephants would be paired with a handler as soon as they get to the rehabilitation centre.  They’ve worked with an individual person who gets to know that elephant and can handle them and really control them and understand their different behaviours and characters.  They ride on top of the elephants and presumably know how to calm them down or speed them up.  But these are people who really understand the elephants.  They play a key part in this study – it wasn’t just the scientists coming in and messing around with the elephants!

What you’re interested in here is the forces on the ball.  If you’ve got air going past the ball the only thing which can touch the ball is air (other than gravity - which we’re going to ignore because it’s not very interesting in these circumstances).  So you’ve got air getting past the ball and so if there’s going to be a force on that ball the air’s going to get deflected one way or the other.  If the with air is deflected to the right then there’s going to be an equal and opposite reaction on the ball it will go to the left and vice versa.

Now what’s going to happen if you put some mud on the right hand side of the ball?  You’ve got air going over both sides of the ball - on the left hand side of the ball, the ball is just as normal and the air’s  going to stick to the edge of the ball and come around as far as it would do normally.  On the right hand side of the ball you’re going to get a whole lot of mud, it’s going to be rough so the air is going to become turbulent and it’s actually going to leave the ball earlier.  So the air coming from the left is going to stick on the ball longer than the air going to the right.  Which means overall the air’s going to start moving to the right which means overall the ball is going to move to the left. 

Helen -   That’s really a good question actually, do other animals have to keep themselves hygienic in that particular area?  As far as we know, we haven’t found any animals that actually have invented a tool for keeping themselves clean in that way.  There maybe jokes about bears and rabbits but they are just jokes.

Chris -   Isn’t it called their tongue?

Helen -   Exactly.  I think most animals do actually just keep themselves clean by washing themselves.  You know what cats can do - they've got the clever trick of putting their leg behind their neck and they keep themselves clean that way.  Another thing some people with cats and dogs might have noticed is their pets  doing something called "scooting", which is dragging their ass across the ground.  Often pet owners get worried about why their dog or cat might be doing this - it is often after they’ve been to the toilet and they wonder if it’s something connected to it.

Chris -   They usually wait until they’ve got into the room with the best and the most expensive carpet...

Helen -   Well there are various factors like that to consider.  But veterinary surgeons really think that it’s likely to be a parasitic infection, it could be worms, they are feeling very itchy and they want to scratch themselves.  It’s also could be an infection of something that is charmingly called the anal glands which are something many predatory animals have.  Either side of the anus they have these glands which produce scent chemicals.  It is where a skunk produces smell from and it’s what makes a fox turd smell like a fox turd and dog turds like a dog turd, and so on.  They use that to mark their territory when they are defecating.  If those get infected they can also be quite painful and that’s why dogs and cats can drag themselves along the ground as well.  And if your pet does seem to be doing that it’s probably best to take them to the vet and get that sorted out.

So no, I don’t think any animals actually use toilet paper but if they need to they will keep themselves clean in other ways.

You can’t convert heat itself directly into electricity because you can’t create or destroy energy, but you can do useful work with it converting it from one form into another.  The forms which energy always converts to eventually are the more disordered forms of energy and heat is one of the most disordered forms.

You can get useful energy, useful electricity, from heat flowing from somewhere which is hot to somewhere which is cold.  We’ve been doing that for hundreds of years, it’s essentially what a steam engine does.  You’re moving heat from a hot fire to the cold outside world.  You can do this just by putting two different metals together, this is called a thermocouple. That produces minute amounts of energy, but it is quite useful for measuring temperatures.  You can get much more energy out using semiconductors, essentially you  build a diode and the hot electrons can go through diode - then they have to flow all the way around the circuit and back to the other side. As they flow around they can do work.

So you can generate electricity through flows of heat but not from heat itself.

Well; mankind first originated and evolved in Africa - what’s probably now Northeast Africa is where the first modern humans originated from.  It’s equatorial; it’s very hot; there’s huge amounts of sunlight.  So the risk there is that people will end up with ultraviolet radiation penetrating their bodies. 

Now, the first thing people think of when you say "ultraviolet" is skin cancer.  But, actually, skin cancer isn’t the sole explanation for why people have black skin.  Most people don’t get skin cancer until after the age at which they would have reproduced anyway and therefore it wouldn’t really have any evolutionary benefit to them to have black skin.

In fact, why they black skin is to prevent ultraviolet radiation breaking down the chemical folate in the skin. 

Folate is really important for the production of DNA.  In order to conserve their reserves of folate, people who were at first evolving in Africa actually evolved to have black skin.  The common ancestor that we share going back in time with, say, chimpanzees about 6 million years ago, those animals all had pink skins but they have fur to protect them.  As soon as they became hairless, our early ancestors had to evolve dark skin to protect them from the sun.

But when they migrated north, out of Africa, and they ended up in high latitudes, like in Britain, where sunlight is something we don’t see very often, there was just not enough sunlight - especially coupled with dark skin - to produce enough Vitamin D which gets made in your skin, so people then became a bit Vitamin D deficient. 

So we lost the genes that made us have black skin in order to produce more Vitamin D.  The benefit of doing that is that you have stronger bones.  The down side is you’re slightly more vulnerable to the ultraviolet in the sunlight, but as there’s much less sunlight it was a worthwhile gamble to take.

The first thing is that any solid object that looks solid to us is actually has huge amount of space in it.  Even in an atom, the nucleus of the atom is about a hundred thousandth of the size of the actual atom.  So there’s immense amounts of empty space only containing electrons which are even smaller than the nuclei, so there’s lots and lots of space for things to travel through as long as it doesn't interact with the nuclei or electrons. 

A lightwave is actually quite big compared to the size of an atom.   It’s a quantum mechanical object - it’s kind of a particle, but it’s kind of a wave.  You can think of it as wave which only arrives in particles - not really something with which we have a handle on.  It’s a lot easier to think of it as a wave in the circumstance.  The only way to stop a wave is with something which will actually absorb it or scatter it and in something like glass there's just nothing there which will absorb or to scatter it.  So it just carries on going in a straight line.

Dave -   It depends on the kind of microscope.  Light behaves a bit like a wave. It has a wavelength.  It’s very, very hard to see things smaller than the wavelength of the light because you essentially get interference effects. The waves interfere and it messes with your picture.  With conventional microscopes it’s very hard to see anything less than the wavelength of light which is about half a micrometer - roughly a 2000th of a millimetre.  There are ways of doing things with light which means you can get a little bit smaller than that, using funky things called metamaterials, but they are not really common.

If you want to get much more magnification than that you need to use something with a much smaller wavelength.  A common one to use is an electron, because although it appears like a particle it’s also a wave and the wavelength is much, much shorter and therefore you can see much, much smaller things.  You can actually see big atoms with a normal electron microscope.  Other forms of microscope involve dragging a tip, it’s called a scanning tunneling electron microscope, and you measure the electric current going between your tip and your object  - with this, you can measure down to large atoms.

Chris -   IBM iconically produced the letters IBM, I think it was 1990-1991, by manoeuvring Xenon atoms with a scanning tunnelling electron miscroscope didn’t they?  I can’t remember quite many atoms they used, 40 or something, and it took them about 2 weeks to move these things around.  People were saying this is the future of computing! 

There was also a story that got published in the middle of 2008.  It was by a researcher at the University of California, Berkley, Jannik Meyer.  This was a wonderful paper because they were able to see hydrogen atoms.  That probably qualifies as the smallest thing you could see because that’s the smallest entity at an atomic level in the Universe. 

The way they did this was they had a sheet of graphene which is a single layer, one carbon atom thick, of graphite and they could drop molecules onto that surface and then scan across it with the scanning tunnelling electron microscope and measure where it was interacting.  The tip was interacting with the different atoms. 

Because the graphene is like a little pattern of chicken wire - it’s a very regular hexagon pattern - it’s very easy to subtract mathematically from whatever signature you pick up, so they can see any atomic species that were dropped on there.  They could even see these little white dots that turned out to be hydrogen atoms; if you put a bigger molecule, like a butane molecule - the stuff that you burn in your lighter - on there, you can actually see this zig-zagging chain of hydrocarbons. It’s just absolutely phenomenal!

Dave -   A battery basically has a little chemical reaction inside which, in conventional ones,  causes the voltage of one end of the battery to be one and half volts higher than the other end.  You can join batteries together and voltage will get higher.  I can’t see any intrinsic limit to how many times you can do that unless you get to a point where the voltage is so huge that you’ll cause sparks from one end of the battery to earth.  It depends how good your insulation is - through air you cause a spark at about a thousand volts per millimetre.  So if you’re getting into tens of thousands, or millions of volts, then you could create sparks.  I think the bigger limit is how much money you have to buy the batteries and how much time you have to join them all together.

Chris -   There was a place in Alaska, about five years ago, where they were having so many frequent power cuts that they decided that they will build a massive great Nickel Cadmium battery to prop up the town every time there was a power cut.  It was something ridiculous like 13,000 NiCad batteries all linked up to produce mains voltage for a short while to sustain the town and overcome the power deficit problems.

Dave -   In the past there have been research batteries at thousands and thousands of volts because it was the only way you can make these high voltages.  Now we have easier ways using electronics.

Helen -   I believe that question came from someone who’s been reading our website - there’s a fantastic article there by Bruce Wright from October 2005 about how there are more sharks appearing in inland waters in Alaska.  That’s one particular case that seems to be going on.  On a global scale, last year in fact, there were lots of news stories about shark attacks on the rise being linked to global warming, but really there was no proper science backing that up.  First of all – is there really an increase in shark attacks?  Well, maybe, but not necessarily for any other reason than there’s more people in the water and they were reporting more shark attacks.  There are only 50 to 100 attacks every year but when there’s a peak that occurs, perhaps over the course of a month or two, people get very excited and think “Oh gosh! Something must be going on!”

Yes, sharks do respond to temperature, there are various ways that can affect them and  warming seas are likely to affect sharks.  A recent study has suggested that the Antarctic could become infested with sharks.  There haven’t been any sharks there for 40 million years but as it’s warming up they could start moving back in there.  That could really affect the ecosystems in those areas.  So yes, sharks are affected by warming seas in ways that we’re just starting to understand.

Chris - We talked about Aspartame last week, and that’s about 200 times sweeter than sugar.  The reason that we use it, of course, is to make things taste much sweeter without having to add additional sugar - because the sweetener molecule has got virtually no calories in it compared to the large amount of calories that are in sugar.  It fools the tongue into thinking things taste sweet because it locks on to the same chemical receptor -  the docking station that recognizes sugar  - making it taste sweet.  In reality it doesn’t actually impart any caloric contribution.  The reason that it also has other tastes is because it doesn’t just recognize the receptor for sugar, it also binds to other flavour receptors as well.