Category: Science history

Categories
Coffee review Observations Science history

A ‘brief’ encounter at Coffee Affair

Coffee Affair, Queens Road Station
The exterior of Coffee Affair, yes it really is inside the station

It was a few weeks ago now that I dropped into Coffee Affair on a Saturday afternoon and met Michael (who runs Coffee Affair along with ‘Mags’). What can I say? This place is worth visiting for so many reasons. Firstly of course there is the coffee, so much care and attention to detail was taken when I ordered a pour over Burundi coffee from Round Hill Roastery. I was warned that my coffee would take some time to prepare before the filter was carefully rinsed and the coffee weighed and ground. The final coffee having been made with such attention that I started to understand why they had chosen the name ‘coffee affair’. It is clear that coffee is a passion.

Parquet floor at Coffee Affair
The floor at Coffee Affair.

Then there is the knowledge that Michael brings to the coffee and is happy to share. Thoughts about the best temperature to drink the coffee for example, or details about different brew methods (there is a lovely array of coffee brewing equipment on the wall of the cafe). One thing that really appealed to me though was the place. There are only a couple of tables and a bar but this emphasises the space that Coffee Affair inhabits: A preserved old ticket office. There are windows looking into the station with bars on them through which the tickets used to be sold. There is the oak table that has had years of ticket sellers leaning on it, presumably with a lamp next to their counter as it would have been a lot darker when it was used as a ticket office. Then there is the flooring, original parquet flooring that dates from the time that the station was built.

If you take a seat towards the back of Coffee Affair and look at the floor you can see where the floor has worn down just that little bit as ticket sellers from years ago shuffled at their counters while selling tickets. Like the toe of St Peter, the floor has been worn away by the number of people in contact with it over the years. Between the counters you can see where someone has tried to polish the parquet to minimise this ‘dip’ but has instead managed to produce lines in a slightly more polished floor. Thinking about the wear of the floor reminded me of Charles Darwin’s musings about the erosion of the Weald in the South East of England.

Goudhurst area
How long does it take for such landscapes to form?

In the first edition of Darwin’s book “On the Origin of Species” (1859), Darwin included an estimate for the age of the Weald of Kent, the area between the chalk hills of the North and South Downs. Based on his observations of coastal erosion, Darwin calculated that the Weald must have been at least 300 million years old. This was perfectly long enough for the gradual evolutionary steps of natural selection to have occurred. As Darwin said “What an infinite number of generations, which the mind cannot grasp, must have succeeded each other in the long roll of years!”* Looking at the floor at the Coffee Affair, you can get a similar idea as to the number of generations that have stood at the ticket windows.

Darwin’s estimate of the age of the Weald led him into an argument with William Thomson (Lord Kelvin) about the age of the Earth (which you can read more about here). It was Kelvin’s argument about the age of the Earth that Darwin considered “the single most intractable point levelled against his theory during his lifetime”†. The argument was eventually settled in Darwin’s favour, once new physics had been discovered, but only after both Kelvin and Darwin had died. So I’ll leave Darwin the last words for today’s Daily Grind, relevant too for those who have the opportunity to study the floor at Coffee Affair: “He who most closely studies the action of the sea on our shores, will, I believe, be most deeply impressed with the slowness with which rocky coasts are worn away”.*

 

Coffee Affair is in the old ticket office at Queenstown Road Station, Battersea,

* Quotes from “On the origin of species”, Charles Darwin (Oxford World Classic’s edition, 2008)

†Quote taken from “Charles Darwin, The Power of Place”, Janet Browne, Princeton University Press, 2002

Categories
Coffee cup science Observations Science history

Perpetual motion in a coffee cup

V60 from Leyas
Could your coffee be used to power a perpetual motion machine?

There can be no such thing as a perpetual motion machine right? Yet less than two hundred years ago it seemed possible that there could be. Not just that, the source of this perpetual motion machine was in your coffee cup. How would you explain Brownian motion?

Brownian motion is the random movement of small bits of dust or coffee/tea particles on the surface of your brew. To see it, you may have to use a microscope though you should take care not to confuse Brownian motion with motion caused by convection currents. There will be Brownian movement even a long time after the coffee has got cold. What causes this continuous movement? When he observed it for the first time in 1827, Robert Brown (1773-1858) had thought it was to do with a ‘life force’. He had been observing pollen suspended in water and noticed that the pollen kept moving under his microscope lens. In 1827, this was a very reasonable explanation, after all, weren’t several people looking for a motion, a force, that gave life?

Sphinx, Brownian motion
Brown used some dust from the Sphinx (shown here with the Great Pyramid) to show that ‘Brownian’ motion could occur in inorganic materials. Postcard image © Trustees of the British Museum

So, he checked if he saw the effect in pollen that was one hundred years old (he did) and then in truly inorganic matter, he looked at the dust from a fragment of the Sphinx. Again he saw the dust fragment move in the water. He had therefore shown that it was not associated with a life force but was something that happened for every small particle suspended in a liquid. What was driving it?

Without knowing what caused it, some people in the nineteenth century had already suggested a device to exploit it, using tiny levers to carry the energy from this continuous motion into devices. Others insisted on finding out what was causing the motion but it was here that the physics of the day hit a philosophical problem. It was proposed that molecules in the water could be hitting the dust on the surface and moving the dust in seemingly random directions. And yet there is a problem with this explanation. At that time there was no way of seeing or measuring molecules. How could physics postulate a theory – or suggest a reality – that could not be tested?

Nasa, Norway, coastline, fratal
How long is a section of coastline? Coastlines can be described as fractal like. Mathematics that grew out of studying random walks and Brownian motion. Image credit NASA Visible Earth/Jeff Schmaltz

An answer came one hundred years ago in a paper published by Albert Einstein (1879-1955) in 1905. In it he made some mathematical predictions that, for the first time, allowed the theory (that it was molecules causing Brownian motion) to be tested by experiment. Jean Perrin (1870-1942) of the Sorbonne, Paris, was the experimentalist who, by careful observation of droplets of water containing a pigment used by water colour artists, provided evidence for Einstein’s theory of Brownian motion. The experiment was so important that Perrin later wrote “.. the molecular kinetic theory of Brownian movement has been verified to such a point in all its consequences that, whatever prepossession may exist against Atomism, it becomes difficult to reject the theory.”

The consequences for our world have been profound. The mathematics that describes Brownian motion is that which we use as the basis to predict the movements of the stock exchange. Extensions of the mathematics have been used to develop new areas of mathematics such as fractals. Even art has grasped the theory of Brownian motion, the Anthony Gormley sculpture “Quantum Cloud” is based on mathematics describing Brownian motion. Everywhere you look there are phenomena described by the movements in your coffee cup. What we have yet to do is find that perpetual motion machine.

Categories
General Science history slow

Of worms and grind

coffee ground, grind, composting
What do you do with your used coffee grounds?

What do you do with your finished coffee grounds? Feed them straight to the plants? Donate them to Biobean to be transformed into fuel? Or perhaps turn them into compost with a worm bin? Ground to Ground is a website dedicated to sharing information about what can be done with old grounds. My preferred option though is the worm bin. Each Chemex of coffee grounds gets put out into the “can-o-worms” compost bin ready to be transformed into compost and plant fertiliser.

I had thought that there could be very little connection between my worms (so to speak) and the Bean Thinking website. However, I recently came across an anecdote about Charles Darwin that, to me at least, unites some of what Bean Thinking is about with my can-o-worms.

can-o-worms, worms, coffee grounds, composting
The top layer of my worm bin. You can just see some coffee grounds but it is mostly cabbage.

Darwin’s last book was “The formation of vegetable mould through the action of worms” published in 1881. After Darwin’s death (in 1882), Edward Aveling (1849-1898) wrote about meeting Darwin years earlier. In “Charles Darwin and Karl Marx: A Comparison” (1897), Aveling wrote: “I remember, in my youthful ignorance, asking Darwin why he dealt with animals so insignificant as worms. I shall not forget his reply, or the look that accompanied it. ‘I have been studying their habits for forty years’.”

By studying what to others looks insignificant, Darwin had made huge progress in our understanding of worm behaviour. This has led to our current knowledge about the contribution of worms to the ecosystem and the benefits of composting our coffee grounds, both for our plants and our planet. It strikes me that we can all benefit from slowing down and noticing what seems insignificant.

Perhaps you do something unusual with your old coffee grounds? Maybe you have noticed something about coffee grounds and worm behaviour. Whatever it is, do let me know in the comments section below.

Categories
Coffee review Home experiments Observations Science history

Joe’s espresso cafe bar, Victoria

radiant heat, heat loss, heat conduction, infra red, Joe's espresso cafe bar
The slightly ajar door at Joe’s espresso cafe

A few weeks ago I happened to be near Joe’s espresso café bar on the corner of Medway St. and Horseferry Road, with around twenty minutes to spare. Joe’s is an old-style independent café, very focused on their lunch menu and take away coffees. Nonetheless, there is a decent sized seating area in a room adjacent to the ‘bar’ where you can sit with your coffee and watch the world go by on Horseferry Road. It is always nice to come across a friendly café that allows you to sit quietly and people-watch. As I sat and watched the taxis pass by, I became aware of the fact that it had got quite cold. The people who had just left the cafe had left the door to the room slightly open; the cold was ‘getting in‘. Now I know, heat goes out, cold does not come in but sitting there in that café that is not how it felt. Then it struck me, rather than cause me to grumble, the slightly open door should remind me  of the experiments of Carl Wilhelm Scheele (1742-1786).

Scheele was a brilliant chemist but one who performed experiments that would make our university health and safety departments jump up and down spitting blood. Recognised for discovering oxygen in the air (Priestley discovered it a few years later but published first), manganese and chlorine, Scheele also investigated arsenic and cyanide based compounds. It is thought that some of these experiments (he described the taste of cyanide) contributed to his early death in May 1786 at the age of 43. Fortunately, none of this has a connection to Joe’s espresso café. What links Scheele with Joe’s, is Scheele’s discovery of ‘radiant heat’ as he was sitting in front of his stove one day.

Open fire, Carl Wilhelm Scheele, Radiant heat, infra red, convection
Sitting in front of a fire we can observe several different ways that heat moves.

Scheele’s house was presumably very cold in winter. He describes how he could sit in front of his stove with the door slightly ajar and feel its heat directly and yet, as he exhaled, the water vapour in his breath condensed into a cloud in the air. The heat from the stove was evidently heating Scheele, but not the air between Scheele and the stove. He additionally noted that this heat travelled in straight lines, horizontally towards him, as if it were light and without producing the refraction of visible light associated with air movement above a hot stove. Nor was a candle flame, placed between Scheele and the stove, affected by the passage of the heat. Clearly this ‘horizontal’ heat was different from the convective heat above the stove. Scheele called this ‘horizontal form’ of heat, ‘radiant heat’.

A few years later, the astronomer and discoverer of Uranus, William Herschel (1738-1822) was investigating glass-filter materials so that he could better observe the Sun. Using a prism to separate white light into its familiar rainbow spectrum, Herschel measured the temperature of the various parts of the spectrum. Surprisingly, the temperature recorded by the thermometer increased as the thermometer was moved from the violet end to the red end of the spectrum and then kept on rising into the invisible region next to the red. We now recognise Herschel’s observation of infra-red light as responsible for the radiant heat seen by Scheele, though a few more experiments were required at the time before this was confirmed.

sunlight induced chemical reactions, milk
Often milk is now supplied in semi-opaque bottles. Why do you think this is?

Further work by William Hyde Wollaston (1766-1828) and, independently Ritter (1776-1810) & Beckmann not only confirmed Herschel’s infra-red/radiant heat observations but also showed that, at the other end of the spectrum was another invisible ‘light’ that produced chemical reactions. Indeed, milk is often sold in semi-opaque plastic containers because of the fact that the taste and nutritional content of the milk are affected by such sunlight induced chemical reactions.

So, it seems to me that, in addition to an interesting story with which to idle away 20 minutes in a café, this set of thoughts offers a variety of experiments that we could try at home. If we are out, we could try to discern the different ways that heat is transferred from one body to another (as Scheele). If we had a prism, we could perhaps repeat Herschel’s experiment very easily with a cheap (but sensitive) thermocouple and, if we were really ambitious hook it up to a Raspberry Pi so that we could map the temperature as a function of wavelength. Finally, we could investigate how light affects chemical reactions by seeing how milk degrades when stored in the dark, direct sunlight or under different wavelengths. If you do any of these experiments please let me know what you discover in the comments section below. In the meanwhile, take time to enjoy your coffee, perhaps noticing how the hot mug is warming your hands.

Books that you may like to read and that were helpful for this piece:

“From Watt to Clausius”, DSL Cardwell, Heinemann Education Books Ltd, 1971

“On Food and Cooking: The science and lore of the kitchen” H McGee, Unwin Hyman Ltd 1986

Apologies to university H&S departments, you guys do a great job (mostly!) in trying to help to prevent us dying from our own experiments too prematurely.

 

Categories
General Science history

A gift fit for a King?

Adoration of the Magi, Andrea Mantegna, 1431-1506. Digital image courtesy of the Getty's Open Content Program.
Adoration of the Magi, Andrea Mantegna, 1431-1506. Digital image courtesy of the Getty’s Open Content Program.

There is currently a very thought provoking painting on display at the British Museum (although it will soon be gone, the Ming: 50 years exhibition, of which it is a part, ends on 5th January). The painting depicts the moment that the three kings, (or three wise men) present their gifts of gold, frankincense and myrrh to the Christ child. The three kings are on the right of the picture. Notice Melchior however, who is presenting gold to Jesus at the bottom of the painting. He presents his gold gift in a porcelain cup. The painting suggests just how valuable porcelain was to the Europeans of the 15th-16th century.

For many years, the Chinese had the monopoly on porcelain production and they ensured that the recipe was kept secret. Nonetheless, by the 17th century porcelain was being traded with Europe and by the 18th century the Europeans had started to mass produce it. Bramah has argued (in the excellent book “Coffee Makers”) that the explosion in popularity of tea and coffee drinking in Europe during the 17th-18th century was due to the introduction of porcelain into general use and its mass production. So it is worth taking a closer look at one of the key figures in the production of ceramics: Josiah Wedgwood.

Wedgwood painting
Portrait of Josiah Wedgwood, FRS. © Trustees of the British Museum

As a ceramics maker, Wedgwood (1730-1795) was interested in ensuring his pottery came out of the furnace well each time and to do that, he realised that he had to know the temperature of the oven. Other pottery producers of the time judged the furnace temperature by the colour (red hot, white hot etc), Wedgwood asked if there was a better way. Eventually he designed a “pyrometer” (“fire” meter) made from bricks of Cornish clay. Wedgwood used the fact that the clay shrank when fired. The amount that the clay shrank indicated the temperature of the oven. Wedgwood could then quantify what was “red” hot etc. Of course, there were problems. Wedgwood’s thermometer worked at temperatures of around 1000ºC, where ordinary alcohol or mercury based thermometers could not be used. How can the temperature scale (that became known as degrees Wedgwood) be correlated with the temperature scales that we are familiar with (such as degrees Centigrade)? Another, perhaps more significant problem was that the technique was not transferable to other practitioners, different clays shrank by different amounts. The Wedgwood scale required a specific Cornish clay. It was left to Louis-Bernard Guyton de Morveau to improve the pyrometer, basing his high temperature thermometer on the expansion of platinum. Today, we use devices based on electrical properties of metals to measure such high temperatures.

A porcelain bird feeder (1426-1435) from the Ming dynasty. © Trustees of the British Museum
A porcelain bird feeder (1426-1435) from the Ming dynasty. © Trustees of the British Museum

If you are in London, it is worth popping along to the Ming 50 years exhibition before it closes on 5th January 2015. Along with this painting, there are many examples there of excellent Chinese porcelain. One of the things that struck me as I went around the exhibition was just how annoyed visiting European diplomats must have been if they ever visited the Imperial palaces. Not only did the Chinese use this rare and valuable porcelain for cups, they also made exquisitely designed, porcelain, floor tiles and bird feeders. While in Europe we were struggling to make any porcelain, the Chinese were not only walking on bits of this valuable material, they were allowing their birds to feed from it too! An interesting history for next time you take a sip from your favourite mug.

Please leave any comments using the form below. I am very grateful to the image reproduction polices of the British Museum and the Getty Museum for the images shown in this article. Information was taken from:

“Coffee Makers”, Bramah&Bramah, Quillar Press Limited, 2002

“Inventing Temperature”, Hasok Chang, Oxford University Press, 2007

 

Categories
General Science history

Time to enjoy a Beethoven coffee

Portrait bust of Beethoven, Anna EG Hoffman, in the British Museum collection © Trustees of the British Museum
Portrait bust of Beethoven, Anna EG Hoffman, in the British Museum collection © Trustees of the British Museum

It is said that Beethoven prepared his coffee by counting, precisely, 60 beans per cup. Biographies of Beethoven certainly suggest that he had a significant coffee habit. Banned by his doctor from drinking coffee towards the end of his life, there are many references to him frequenting coffee houses in earlier years. Sadly, I have not found the source for the 60 beans story and so would not like to comment on its veracity. Nonetheless, it is a good story and it does link with coffee so, as today (17th December) is the 244th anniversary of his baptism (it is assumed that he was born the day before on 16th December 1770), it is “Beethoven day” on the Daily Grind.

To me, what lends some credibility to the 60 beans story is the fact that, as coffee lovers, we can be very particular about the way we prepare our brew. Some people, for example, weigh the amount of the coffee and the quantity of water and brew their coffee according to instructions from one of the various online brewing tutorials (see here for a good one from Hasbean). Personally, in the morning, I am far too bleary eyed to consider getting the kitchen scales out, nor would I count a certain number of beans. I do however count the number of seconds that I take to grind my coffee with my trusty burr grinder (always set to the same level of grind of course). Can counting the number of seconds for a quantity of grind possibly be a good way of measuring a specific quantity of coffee?

Did Galileo drop balls from the top of the tower?
Did Galileo drop balls from the top of the tower?

Galileo Galilei (1564-1642) died before coffee was properly introduced to Europe. He is relevant to this story though owing to his work on clocks and timing devices. One way that Galileo measured time was to collect water in a jug over the measurement period. It seems that this is almost the reverse of my morning coffee ritual. To check that he was measuring time correctly however, he needed a second, independent method. Of course, Galileo couldn’t use a watch or pendulum because watches hadn’t been developed at the time and Galileo himself was doing the work needed to understand pendulums and make them useful for clocks. So what else could he use to measure time? There is a clue to another method that Galileo used in his experiments on falling balls. Although there are questions as to whether Galileo really did drop balls from the top of the Tower of Pisa, we do know that he did experiments which involved rolling bronze balls down a groove. Along the groove were marks where strings made from gut had been pulled across the groove such that they made a sound as the ball passed, perhaps like the sound of a harp being plucked. By adjusting the position of these strings, the interval between the sounds from different gut strings could be made to match a known rhythm. The time it took for a ball to fall down the groove was being measured by matching its descent to a known tune. This suggests that Galileo sang while he was making his key measurements and that it was this that allowed him to start to understand how bodies fell under gravity. Singing was Galileo’s (surprisingly accurate) method of measuring time.

Which brings me full circle back to Beethoven. Beethoven certainly knew the “mechanician” Mälzel who invented the metronome as we now know it. There are also indications that Beethoven was aware of early versions of Mälzel’s invention. In 1813, the Wiener Vaterländische Blätter wrote “…Herr Beethoven looks upon this invention as a welcome means with which to secure the performance of his brilliant compositions in all places in the tempos conceived by him, which to his regret have so often been misunderstood“.  It seems that in the two hundred years between Galileo and Beethoven, there had been so many improvements to clocks and timing devices that singing, which had started off as a way to measure time, was now itself being regulated by the clocks that singing may have helped to develop.

How many beans go to make your morning coffee?
How many beans go to make your morning coffee?

So how is a Beethoven coffee, assuming that there is any veracity to the legend? Sixty beans works out as 8-10g which, depending on the amount of water in the cup could be weaker (or stronger) than modern brews. In my cup, it was slightly weaker than I am used to. I enjoyed my “Beethoven coffee” while listening to his String Quartet Op 74, “Harp”. As I sipped the coffee while listening to the first movement, I could almost hear the gut strings of Galileo’s experiment being plucked as the balls rolled by. The coffee itself (Costa Rica, Finca Arbar El Manatial, Yellow Honey, Caturra/Catual) was very smooth and rich, as you would expect from a coffee from Has Bean. Described in the tasting notes as “….An amazing caramel and milk chocolate sweetness partnered with delicate peach and apricot acidity…” It was the perfect coffee to enjoy with the Harp quartet piece. Sometimes it is important to take time to go slow and enjoy the coffee.

So why not raise a mug today to Beethoven and savour a Beethoven coffee? Please leave any comments using the form below, especially if you know a reliable reference to Beethoven’s coffee habit or have suggestions as to how to improve my morning brew.

Further reading:

Quotes taken from “Thayer’s life of Beethoven”, Revised and Edited by Elliot Forbes, Princeton University Press, 1967

Information on Galileo and time: “Styles of Knowing, A new history of science from ancient times to the present”, Chunglin Kwa, University of Pittsburgh Press, 2011

Categories
Coffee review Observations Science history

Calming the waves at Brutti & Boni

Brutti And BoniBrutti & Boni is a fairly new Italian cafe in South Kensington. Located at the less busy end of Gloucester Road, it was quiet when we popped in to try it a couple of weeks ago. The bright interior has light coming from a roof window at the back of the shop, though it seems that many people opt to sit outside with their espresso in the morning, watching the traffic go past. They serve Caffe Molinari coffee together with a good selection of Italian food items. All in all, a good place to go if you are in the area visiting the Science, Natural History or Victoria and Albert museums and fancy a break and a relaxed coffee nearby.

Inside, the shelves are stacked with various Italian condiments, pasta and olive oil. It was this that prompted me to visit Clapham Common to retrace the steps of Benjamin Franklin. Franklin of course was one of the founding fathers of the USA. He was also a keen scientist, diplomat, printer, in fact the man in some ways defines the word “polymath”. His interests and importance span so many areas that it is difficult to write a two-sentence description of him. Fortunately, for the purposes of today’s Daily Grind, I do not need to. Today, all that is important is that Franklin did some experiments on Clapham Common with oil.

Shelves of olive oil at Brutti & Boni
Shelves of olive oil at Brutti & Boni

Franklin had been investigating the “old wives tales” that a small amount of oil placed onto water ‘calmed the waves’. In fact, the old wives tales can be traced back to Pliny (the Elder) in his Natural History written in around 77AD. Pliny had written of pearl divers and how they sprinkled oil on their faces so that the water above them became calm, allowing them to see the oysters that they were looking for on the sea bed. Franklin himself describes, in his letter to the Philosophical Transactions (1774), an event that he experienced in 1757 while sailing to the UK. Noticing that the wakes behind two of the boats in the fleet were calm, he describes how he asked his ship’s captain about this curiosity. Replying slightly dismissively, as if to someone who is quite ignorant of the workings of the world, the ship’s captain replied that “The cooks… have I suppose been just emptying their greasy water through the scuppers, which has greased the sides of these ships a little”. Obviously it was common knowledge that oil calmed the waves.

So, one day in the 1760s, Franklin took a walk to Clapham Common and to Mount Pond. Emptying about a tea-spoonful of oil (oleic acid) into the pond he watched as the oil produced an “instant calm [on the pond] over a space several yards square, which spread amazingly, and extended itself gradually till it reached the lee [opposite] side, making all that quarter of the pond, perhaps half an acre as smooth as a looking glass.” Oleic acid is the principal component of olive oil. Franklin had effectively calmed the waves on the pond with a mere tea-spoonful of olive oil.

A view over Mount Pond, Clapham Common
A single tea spoon of oil would calm the ripples on Mount Pond, Clapham Common

We can calculate how thin the layer of oil had become by dividing the volume of oil in a teaspoon (5cm³) by the area of half an acre (2023 m²) to get an oil layer that was 2.5 nm thick. To put this in perspective, a coffee bean of width 7 mm would fit nearly 3 million of such oil layers in itself width-wise. Later, more precise, measurements of the thickness of such an oil layer, by Lord Rayleigh and Agnes Pockels, gave 1.6 nm and 1.3 nm respectively. This is approximately the length of a single oil molecule. It seems that the waves on water can be stilled by a single molecular layer of oil. How does this work? Why not let me know what you think in the comment section below.