Richard Sear

The Tin Man Lecture

In The Wizard of Oz, the Tin Man is seeking a heart. Lacking a heart is taken to mean that you cannot love. This is poor science of course, our emotions are felt by our brain, and our heart is a pump. Without a heart, our blood would not be pumped around our body, our tissues would be starved of oxygen and food, and we would rapidly die.

In Friday’s lecture on biological physics I covered why we and all animals bigger than roughly a few millimetres need hearts, why we need pumps to pump fluid round our bodies. The reason is some simple physics: We need pumps as without the flow pumps produce, molecules such as oxygen would only diffuse around our bodies. I am about 1.85 m tall. Diffusion is agonisingly slow over distances like that. Oxygen takes decades to diffuse over a metre. This is far far too slow to support life. Hence the need for a pump.

Has modern medicine run out of luck?

This week I have mostly been doing 11 contact hours of teaching plus prep for that, and a little reading of James Le Fanu’s interesting if a bit depressing book The Rise and Fall of Modern Medicine. The 11 contact hours included six on Friday in which rather ridiculously I introduced the beautiful symmetry of the cowpea mosaic virus to two entirely different audiences on the same day — one at 11:00 am and the other at 2:00 pm. I was doing my best at 2pm but it was a long week, so I had probably had a bit more enthusiasm in the morning.

Six chances to win, yet sadly I still miss out

Over the last two days, six physicists have won Nobel Prizes, but just like last year, and the year before, etc, I missed out. Ah well, it could have been worse, at least actual biologists won the Nobel in Physiology or Medicine. Yesterday, three physicists changed the light bulb, forever, and were awarded the Nobel Prize in Physics. Today, three physicists saw smaller things than they should have been able to, and picked up the Nobel Prize in Chemistry. They won it for developing techniques for imaging with light, objects that are smaller than the wavelength of the light. The effect is illustrated in the figure up top of this post, on the left is a living cell imaged using a conventional microscopy — details are blurred by the size of light photons we are using to image the cell. On the right is the cell imaged using one of the techniques that got the prize. There you can see individual spots in the image, these spots are the locations of individual protein molecules .

No choice but to be beautiful

The beautiful structure to the left is a reconstruction of the protein shell of the cowpea mosaic virus. This is a virus that infects the cowpea, a type of bean cultivated in warmer climes than the UK*. Viruses are the simplest form of life. They simply consist of a protein shell that contains and protects their genetic material, which is inside this shell. This virus’s coat is made of 120 molecules, of just two different types of protein – shown in green and yellow here. Inside are two molecules of RNA that cary the virus’s genes, plus a couple more proteins.

It’s official, banana skins are dangerous

I love the IgNobel prizes, they’re great. Their stated aim is to make you laugh and to think, and what is better than having a laugh and thinking about something new? This year’s winners were excellent as usual. I particularly liked the 2014 Physics IgNobel.

Ola Brazil! Hello Switzerland!

One of the nice things about WordPress is that it shows the countries people are in when they read this blog. The result for about 7 months of this blog is below. Somewhat to my surprise, Brazil is in 4th place. Hello nice people from Brazil! At the other end of the spectrum, in 7 months only a single post has been viewed from Tunisia. Hope I haven’t offended my one Tunisian reader.

Giants in Chihuahua

We take crystals for granted, maybe because they are so common. The Earth’s crust is crystalline, as are our cutlery, and even our bones and teeth are partly crystalline. But crystals are remarkable things. Although most crystalline materials are made of many tiny crystals mushed together (our bones are like this), sometimes huge single crystals can grow. There are crystals in the Naica mine in the Chihuahua state* of Mexico that are over 10 cubic metres in volume. This corresponds to maybe 10³⁰ atoms. And in a single crystal, all atoms are on the same crystal lattice, all 10³⁰ of them here. So the relative positions of pairs of atoms in one corner of the crystal are the same as in the opposite corner over 10 metres or more than 10 billion layers of atoms away. That’s a lot of layers, and presumably they grew one at a time. These big crystals may have started growing before the first civilisations arose in what is now Egypt and Iraq, thousands of years ago. The growth of large perfect crystals can be a slow business.

Frogs and snails, And puppy-dogs’ tails

According to the nursery rhyme* I was told when I was a child, boys are made from “Frogs and snails, And puppy dog’s tails” while girls are made from “Sugar and spice, And everything nice”. I am rewriting my biological physics lectures to talk a little bit about what we are really made of. This does include sugars, but is mainly water, protein, fats and related molecules, and mineral. We are roughly half water, with the remainder 20% protein, and 10% each of lipids and the mineral in our bones. Lipids are the molecules that make up the membranes in our cells as well as what we call fat. There are smaller amounts of lots of other stuff, like sugars, DNA, etc.

Is British science meritocratic?

I think UK science is pretty meritocratic, certainly few seem to care where you went to school or university. But there have been some alarming newspaper articles on some professions being dominated by those who went to private schools; for example 71% of judges were privately educated. They don’t report figures for science*. And at yesterday’s Open Day a parent of a prospective student asked a colleague and I about how much employers care about where a physics graduate does their degree. We both thought that most would judge an applicant mostly on their merits although the prestige of their university is not completely irrelevant.

Are university degrees a Veblen good?

A general election is coming, in May 2015. The political parties will be aiming to put out policies for university education in the run-up to the general election. Labour seem to be going for reducing fees from £9,000 to £6,000. The Conservatives, as a matter of principle, like both free-market competition and low taxes. But here these two, competition and spending less taxpayers’ money, may contradict each other.