experiments

Communities at Wilton Way

exterior of Wilton Way, Hackney Coffee

Wilton Way cafe on Wilton Way

There are two things that may strike you as you walk past Wilton Way café. The first is the prominent La Marzocco espresso machine on the counter. The second is the “ON AIR” sign in the corner next to the window. Indeed, it is best to look out for these two as there didn’t seem to be any other sign indicating that this café was the Wilton Way cafe, home to the London Fields Radio that is broadcast from here (hence the “on air” sign). In the late afternoon, the café offered some shade on a sunny day and so we popped in for a tea, though there is seating on a bench outside should you wish to enjoy the Sun. Although this website is supposed to be about coffee (which is roasted by Climpson & Sons), sometimes a fresh mint tea is what is needed. This particular mint tea was very refreshing with plenty of mint leaves in the cup. Sadly though, in what seems to be a common pattern at the moment, this was another café at which there were few cakes on offer, presumably as it was late afternoon by the time we visited. However, what is sad for the mind is perhaps good for the waistline, we’ll have to revisit in the morning for the cakes next time.

Corrugated iron supported the counter while the (plentiful) seats inside the café appeared to be made of recycled wood and boxes. Interestingly, this is mentioned in the description of the Wilton Way café on the London Fields Radio website, apparently the interior was designed to be a mix of modern and reclaimed materials. Choosing a seat at the back allowed us to survey the space and people-watch while sipping the tea. On the counter was an old-style Casio cash register while in the far corner at the front of the café, the microphone and broadcasting equipment stood waiting to be used for the London Fields Radio.

the broadcasting equipment at the WW cafe Hackney

London Fields Radio, broadcast from Wilton Way cafe

In the book “Radar, how it all began” the author, Jim Brown reminisced about how he had played with a crystal radio set as a child in the 1920s¹. Many scientists can remember making their own radio sets as children (or indeed as adults). It seems playing with things, taking them apart and building them again is part of the personal-history of many scientists and engineers (particularly experimental ones whether they be ‘professional’ scientists or not). The Lunar Society (which was active at the end of the eighteenth century and into the early nineteenth) featured a group of keen “tinkerers”. These were people who experimented with nature and invented new devices in order to explore their understanding of the world. Though each of them were only doing science ‘on the side’ as they each had other day-jobs, individuals within the group did make some important contributions to our understanding of the world. One such contribution was by Josiah Wedgwood who by observing the “waviness of flint glass” noticed its resemblance to “that which arises when water and spirit of wine are first put together before they become perfectly unified”². The reference is to mixing fluids of different density. Isn’t this experience of tinkering with things similar to our enjoyment and appreciation of coffee? The more we experiment, the more coffee we try (including cupping coffee as with this how-to from Perfect Daily Grind), the more deeply involved in coffee we become and the more we value it. Isn’t it actually true that in order to deepen our relationship with coffee we need to explore it (and experiment with it) more fully? Cannot the same be said for our relation to our world?

interior of Wilton Way cafe

The view from the corner. Spacious and quirky, the Wilton Way cafe has plenty to offer the coffee (or tea) drinker who wishes to slow down and appreciate the moment.

But then a second thought that, to some extent flows from the first. No development would be possible without a community, each contributor bringing a different talent but each contributing to an idea of a greater good. The London Fields Radio would not be possible without the scientists and engineers who design and optimise the broadcasting (and receiving) equipment. But neither would it be possible without talented DJs and musicians, thinkers, poets and performers to give us something to listen to. Two more groups of people are needed for London Fields Radio to be a success. Those who provide the space for the broadcasting equipment (i.e. the café) and those who listen in. Again there is an analogy with coffee. No cup of coffee could be there for us to enjoy without the farmers, the traders, the roasters, the baristas and finally many other people like us who enjoy a good cup. And the more each of us tinker with appreciating another’s work (cupping the coffee like a roaster or tending an allotment to appreciate the growth), the more of a community we become and the better coffee we get for it. We do not imagine while ‘cupping’ coffee that we are really about to take on the role of the coffee trader or roaster, yet by playing at their job we can appreciate their importance and skill more and so realise more effectively our own role too. We could go full-cycle here and consider how playing with radios and experiments can help us to understand the role of technology and science in society and our participation in it, but perhaps that is left as a point to ponder in another café: How can we each contribute to a better society, understand our role in it and appreciate the contributions of others?

One final thought that came from the Lunar society but appears to have a very contemporary relevance. Wedgwood once said to Richard Lovell Edgeworth “But in politics… as in religion, hardly any two people who thought at all, thought exactly alike on everything.” The main thing was “to agree to differ, to agree on impartial investigation and candid argument”.² It appears the Lunar men still have a thing or two to teach us.

Wilton Way cafe can be found at 63 Wilton Way, E8 1BG

¹Radar, How it all began, Jim Brown, Janus Publishing Ltd, 1996

²The Lunar Men, Jenny Uglow, Faber & Faber, 2003

Clouds in my coffee

clouds over Lindisfarne

How do clouds form?

Does your coffee appear to steam more next to a polluted road than in the countryside?

This is a question that has been bothering me for some time. Perhaps it seems an odd question and maybe it is, but it is all about how clouds form. Maybe as you read this you can glance out the window where you will see blue skies and fluffy white clouds. Each cloud consists of millions, billions, of water droplets. Indeed, according to the Met Office, just one cubic metre of a cloud contains 1 hundred million water droplets. We know something about the size of these droplets because the clouds appear white which is due to the way that particles, including water droplets, scatter sunlight. Clouds appear white because the water droplets scatter the sunlight in all directions. In contrast, the particles in a cloudless sky scatter blue light (from the Sun) more than they scatter red. Consequently, from our viewpoint, the scattered light from the clouds appears white while the sky appears blue. The sort of directionless light scattering that comes from the clouds happens when the scattering sites (ie. the water droplets) are of a size that is comparable to, or larger than, the wavelength of light. This means that the water droplets in a cloud have to be larger than about 700 nm in diameter (or approximately just less than a tenth of the size of the smallest particle in an espresso grind). The particles in the atmosphere on the other hand scatter blue light more than they scatter red light because they are smaller than the wavelength of the blue light. You can find out more about light scattering, blue skies and cloudy days, with a simple experiment involving a glass of milk, more details can be found here.

glass of milk, sky, Mie scattering

A glass of (diluted) milk can provide clues as to the colours of the clouds in the sky as well as the sky itself

So each of the one hundred million water droplets in a cubic metre of cloud is at least about a micron in diameter. We can then estimate how many water molecules make up one droplet by dividing the mass of a droplet of this size by the mass of one water molecule. This turns out to be more than 1000 million water molecules that are needed to make up one droplet of cloud. So, 1000 million water molecules are needed for each of the 100 million drops that make up one, just one, cubic metre of cloud. These numbers are truly huge.

But can so many molecules just spontaneously form into so many water droplets? Unlike a snowball, the water droplet in a cloud cannot start very small and accumulate more water, getting larger and larger until it forms a droplet of about a micron in size. Water droplets that are much smaller than about a micron are unstable because the water molecules in the drop evaporate out of it before they get a chance to form into a cloud (precise details depend on the exact atmospheric conditions). Water droplets need to come ‘ready formed’ to make the clouds which seems unlikely. So how is it that clouds can form?

Condensation on mug in CGaF

Look carefully at the rim of the mug. Do you see the condensation?

It turns out that the water droplets form by the water condensing onto something in the atmosphere. That something could be dust, or salt or one of the many other sorts of aerosol that are floating around in our skies. Just as with a cold mug filled with hot coffee, the dust in the air gives the water molecules a cold surface onto which they can condense. This sort of water droplet can ‘snowball’ into the bigger droplets that form clouds because the water is now condensing onto something and so does not evaporate off again so easily. At the heart of each water droplet in a cloud is a bit of dust or a tiny crystal of salt. Which brings me back to my question. It is much more dusty along a polluted road  than it is in the clean air of the countryside. Is this going to be enough of an effect to affect the probability of cloud formation? Does your coffee steam more as you cross the road than when you walk through the park?

It is a question that demands an experiment (and associated video). Last year, the Met Office suggested this simple experiment for observing clouds in a bottle. Unfortunately however, I have yet to make this experiment work in a way that would allow me to test whether polluted air produces thicker clouds than cleaner air. If you have any suggestions as to a good experiment (that will work on camera!) please let me know either in the comments section, by emailing me, or on Facebook. In the meanwhile, I’d be interested to know what you think, so if you think this post is about you, please let me know.

 

 

Dynamical similarity

Science involves designing experiments to test theories. I do not want to get distracted here by how a theory is defined or the precise ways in which a theory is tested by experiment. The point of this week’s Daily Grind is to look at the role of experiments in physics, where they can be used, where it is more difficult to use experiments to test hypotheses and, how this can be connected with coffee. Some physics can be relatively easily tested by observation or experiment: we can for example take photographs of distant no-longer-planets to test theories about the evolution of the solar system or measure the viscosity of a liquid as we add something to it. Yet there are some areas of physics where it is not immediately obvious how you would test any theory that you develop. One such area is atmospheric physics where the limitations of living on one planet with one atmosphere where many different things all happen at once, could potentially be a bit of a problem for doing experiments on the theories of atmospheric physics.

Fortunately, there is a way in which atmospheric physicists can test their theories with experiment and, perhaps unsurprisingly for the Daily Grind, that way involves a cup of coffee (or tea). The route out is called “dynamical similarity” and it is a consequence of the fact that the same mathematics describes much of that which happens in a cup of tea as it does the atmosphere. It is true that a tea cup is a lot smaller than the atmosphere but a vortex in a tea cup is the same as a vortex in the atmosphere even if one is only a centimetre across while the other has a core size of many kilometres. The mathematics will be the same. This allows people to test hypotheses formed about the atmosphere in an environment that they can control and repeat.

A vortex in the atmosphere

… is a vortex.
(Typhoon Nangka, Image Credit: NASA image courtesy Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption by Kathryn Hansen)

A couple of months ago, I wrote an article in Physics World about the connections between coffee and physics. Shortly after it came out, I got an email from Paul Williams alerting me to an article that he had written in the journal Weather called “Storm in a tea cup“. It turns out that the subject of his research had been to study the impact on the weather of the interaction of two types of atmospheric waves: Rossby Waves and Inertia-gravity waves. The method that he had used to test this was, if not quite a tea cup, a bucket which he could rotate. Rossby waves and inertia-gravity waves are both present in the atmosphere and can be induced, albeit on a smaller scale, in a bucket. He was using the concept of dynamical similarity to explore what happens in our atmosphere. And the experiment was important. Before his experiments, it had been thought that the effect of the interaction of these two sorts of waves was minimal. His experiments revealed that this may not be the case, the inertia-gravity waves can significantly affect the Rossby waves. Given that Rossby waves are responsible for cold/warm fronts and weather phenomena in mid-latitude regions of the world (such as the UK) his results, and his cup of tea, were potentially very important.

I’m always very happy to hear about what others are doing with science in a tea cup or a coffee mug. Please share any thoughts in the comments section below.

Paul Williams “Storm in a tea cup” can be found in Weather, 59, (4), p.96 (2004) 

With apologies to Gertrude Stein.

Introducing Bean thinking

As this is the first true blog post, let’s do the introductions. What is Bean thinking and who is @thinking_bean?

Breakfast coffee, introductionThe human bean behind @thinking_bean has worked for a fair few years in university research centres, researching obscure but fascinating areas of physics where magnetism meets superconductivity. Such research fields can be very beautiful but perhaps not of immediate technological relevance. Understandably, this can cause some in our society to question the utility of investigating these phenomena. Part of the motivation behind Bean thinking is to explore this question, why do we do science?

A second motivation is to share the wonder of the world that today’s understanding of physics gives us. Some of these beautiful areas have not yet been fully understood even though they occur in something as apparently simple as a coffee cup. Through teaching, outreach, talking to friends and even in conversations with some colleagues, I became aware of the way that science, perhaps particularly physics, can be perceived as a very interesting, but perhaps very difficult subject, far removed from people’s everyday lives.

Yet this is not true! Slow down, put down your smart phone, e-book or tablet, observe the world. Physics is all around you. Warming your hands around a mug of hot coffee, you may not realise how it is related to the Big Bang. Looking at a glass of milk can illustrate the reasons that the sky is blue. Even the mere act of stirring coffee can be related the Heathrow minute (link, link2).

Hence Bean thinking, which hopefully will become a space where curious individuals can come and discuss interesting phenomena that they notice in the day to day. If this can be done with a cup of coffee, all the better. The point is to slow down and start noticing. Each Wednesday I will update the Bean thinking blog, the “Daily Grind” with things that I have noticed or that I find interesting. Who knows, if anyone starts to read this and shares their observations perhaps the Daily Grind can also include these. As this website develops, I may add a forum, but for the moment, please let me know what you think about the concept and what you observe around you in the comments section below.