What is Project 68? Kings Cross, London

Project 68 on Tavistock Place. Most of the seating is inside with four benches outside.

Opposite a post box that is more than a century old, there is a cafe on Tavistock Place with the unusual name “Project 68”. Located along a well-used cycle route, when the cafe appeared last year, an obvious question kept springing to mind: what is Project 68? The opportunity to find out and try the coffee came the other weekend on a cycle up to Highbury. Jumping off the cycles at the junction, we had to walk past a couple of black board signs advertising the cafe. “Come this way for really, really good coffee” the signs said. Should we believe it?

The coffee is roasted and supplied by SEND which stands for “Special Educational Needs and Disabilities”. This coffee roasting company works to help people with special educational needs and/or disabilities gain employment as baristas within the coffee industry. As well as working with a few London cafes to train and mentor prospective baristas, the company also sells its coffee to other cafes, such as Project 68. The counter at Project 68 had a large supply of pastries on that Saturday morning which were tempting but we were on our way for lunch. Along with the usual suspects of coffee ‘types’, hot chocolate was available as three varieties, ‘white’, and two differing cocoa percentages. The chocolate was supplied as large buttons, so one hot chocolate was two buttons. Presumably this would allow you to mix the chocolate types should you feel the need.

Inside felt very wooden, in a good way. Light shades of wooden seating complemented the wide windows onto the street. The fact that we had our bikes meant that we went back to sit outside to observe what was happening in this cafe. It seemed appropriate to start by pondering the name. What would “Project 68” refer to? A quick (pre-visit) look on duckduckgo suggested that project 68 referred to a set of Soviet era battle cruisers. This seemed very far from the feel of the cafe. An alternative could be the social riots that occurred in Paris in ’68. And although Project 68 is fairly close to some major London universities again, this didn’t seem to be the feel of the cafe. Looking around, and at the door of the cafe a more mundane explanation suggested itself. The cafe is located at 68 Tavistock Place. Was the name merely a reference to the address?

A board on Hunter St advertising Project 68 just around the corner. Could there be physics connections here with font types or stripy bollards?

Returning to the coffee. We sat outside with our bikes and then the barista brought out our long black and oat milk hot chocolate. Perfectly enjoyable, we sat back and continued to notice what we could observe. The aforementioned postbox almost jumped out at us. The cypher on the front suggesting it dated from the short reign of Edward VII (reigned 1901-10). Among other things, Edward VII had been known to run the clocks at his residence in Sandringham, 30 minutes fast. Much like daylight saving time, this extra half hour meant that there was even more daylight for hunting for him. In the UK, the clocks are brought forward and put back by one hour in March and October respectively each year. It is a desire for our own convenience set against the unchanging regularity of the Sun being directly overhead at mid-day. We could pause to think on that or get distracted by a musical connection to Edward VII as he opened the Royal College of Music in 1883. For while we are considering the music, we may start to notice the connection between this cafe, music, and the stars, and we noticed it just beneath our feet.

Many of London’s older houses and shops have an under-pavement cellar. In the past this would have been used as a coal storage area, now they find many diverse uses. A grate beneath our feet indicated that we were above such a cellar. Suddenly, just after a sip of coffee, there was a whir from beneath the pavement. A rhythmic motor-like noise below where we were drinking our coffee. A stray leaf on the mudguard of my bike indicted a draft coming from the grate too. What was this machine that had sprung into action? It is telling that we can discern many things from how something sounds. We know if our coffee grinder is working correctly by the characteristic hum of the rotation of the burrs. A problem with a vacuum cleaner is often indicated by the regular sound of the motor being disturbed by the clatter of a coin going up the vacuum pipe. Sounds can reveal what is happening in much the same way that we use our eyes to see. But fundamentally a sound is a vibration. Something is vibrating that causes the air adjacent to it to oscillate sending forth a sound wave of a varying note. The mechanism is the same whether we are considering the rotation of the drum of a motor or the subtle vibration of the internal cavity of a violin. Sometimes we can see the cause of the sound as when we notice the fast vibration of a guitar string after it has been plucked. Sound can be ‘heard’ through at least three of our senses (hearing, seeing, feeling).

Finally, it is all about the coffee. A long black balanced on one of the benches. You can see the grate on the pavement to the left of the photo.

On Earth we use sound to detect earthquakes around the world, listening for the vibrations through the ground. Often these vibrations are amplified by detectors changing the subtle oscillations of the Earth into wild wobbles of a pen drawn on paper (or now, into a more digital form). In this case, the sound is transferred to what we see. Recently, there has been the opposite case. Astronomers have noticed, by looking at different stars how each star can vibrate with different sorts of ‘note’. Just like a violin, the internal vibrations in the star will cause the surface of the star to wobble and oscillate according to different types of vibrational sound. And, just as with the Earth, how those vibrations travel around the star and persist with time reveals the composition of the interior of the oscillating sphere. Astronomy provides a further connection to Tavistock Place, if not quite Project 68. The site of Francis Baily’s home is just down the road from Project 68, at number 37. Although he does not seem to be commemorated with a blue plaque (yet?), there are plaques nearby to Lenin and Jerome K Jerome. Clearly this street has quite a history. Baily was an astronomer mostly commemorated now by “Baily’s beads” a phenomenon visible during total or annular solar eclipses. Observed by Baily in 1836, the beads are bright spots of light around the rim of the dark circle of the Moon blocking the Sun. Caused by the mountains and craters on the Moon’s surface, it’s a visual, rather than audible clue as to something slightly off-tone, or irregular, on the Moon’s surface.

Back at the cafe, the sound continued under our feet. Fairly uniform, it seemed like a machine running regularly. We guessed at what could be producing the noise. Nothing was conclusive. Perhaps it is more intriguing if the cause of the sound remains a mystery, just as the name of the cafe.

We returned our coffee cups to the counter inside the cafe and wandered off across the road to Judd Street, ready to cycle off to Highbury. As we were just about to peddle off, a couple of people were walking towards us. “What is Project 68?” one of them asked the other. There can be no such thing as a stupid question and if you would like to find the answer to this one with a lovely cup of coffee with a story, it is worth a diversion to 68 Tavistock Place.

Project 68 is at 68 Tavistock Place, WC1H 9RW

Musical Coffee

Tasting notes from Finca San Cayetano coffee

Tasting notes from Hasbean’s Finca San Cayetano coffee

A few weeks ago, I chanced upon an article “Listening to Stars Twinkle” (link) via Mr Gluckin on Twitter. At very nearly the same time, I received in the post, a new coffee from Hasbean (link) which suggested an entertaining coffee (see pic).  A perfect time to have some fun with coffee, I think.

The article was about ‘stellar seismology’: Understanding the inside of a star by watching sound travel through it. We know from daily experience that the way sound travels through air depends on the temperature of the atmosphere.  Sounds can appear to travel further on cold evenings than on warm nights for example (for an explanation of this effect click here). Conventional seismology on earth uses the same principles. By measuring how sound is deflected as it travels through the earth, geologists can work out the type of rock in the interior of the earth (and whether the rock is solid or molten).

Burmese bell, resonating bells, stars

A bell rings with a note that depends on the composition (bronze) and shape of the bell. © Trustees of the British Museum

Unlike these earthly examples though, ‘listening’ to a star is not so easy.  We cannot hear stars vibrate as sound travels through them. We can only view them from a distance.  It is therefore very fortunate that the surface of a star will start to move noticeably as the sound travelling through the star hits one of the star’s ‘resonances’. Just as a bell has a tone depending on its shape and what it is made of, so a star has a series of ‘notes’ that depend on the composition and temperature of the star. These ‘notes’ are the star’s resonances and we can find out what they are by watching the different patterns on the star’s surface. Each resonance has a distinct, signature pattern which is dependent on the ‘tone’ of the resonance, much like the patterns you can see on the surface of a coffee by dragging a take-away cup across a table. The temperature and composition of the interior of the star determine the ‘notes’ of the resonances and so, by looking at the surface vibrate we can work out what is inside a star.

Can we illustrate this with a cup of coffee?  Of course we had fun trying.

In the video, the hot coffee is poured into a take-away cup that I have previously made into a loud speaker.  In the next few days I will upload details of the making of the speaker onto the Daily Grind. Hooking up the speaker to my phone, I could easily play music through the cup (and through the coffee).  But by connecting the cup-speaker to the phone with a tone generator app installed (free and downloadable from the app store for iPhones and probably similar for Android phones) I could generate single ‘notes’ through the speaker from 1Hz to 20 kHz.  Our ears are only sensitive to frequencies from approximately 20 Hz-20 kHz so below 20 Hz we cannot hear the notes being played.

home made loud speaker, coffee cup, kitchen table physics

The coffee cup speaker in an improved design

Nonetheless between 12 and 13 Hz, the surface of the coffee started to show a lot of movement. Although the distinct patterns of a resonance could not be seen (perhaps the speaker, lighting or other experimental conditions needed optimising), we can clearly see the coffee resonate as the surface is vibrating so strongly at these frequencies. As the tone was changed to down to 10Hz or up to 14Hz, the vibrations faded. The ‘resonance’ of the hot coffee filled cup-speaker was 12-13 Hz.  If the cup were to be filled with yoghurt or only half filled, we would expect the ‘note’ at which the surface vibrated to change. Indeed, in this latter case, I could no longer find the resonance anywhere near 12-13 Hz.

‘Listening’ to the coffee by watching its surface means that we can, in principle, work out the properties of the coffee, its temperature, density etc.  And it is in this way that we ‘listen’ to stars ‘twinkle’ so as to understand our universe more.  So thank you MrGluckin and Hasbean for providing an entertaining couple of weeks for me!  Please try this at home and let me know what you discover in the comments section below.

Important Disclaimer: No coffee was wasted in this experiment! I had already finished drinking the contents of the cafetiere and just used the old grounds to provide the ‘coffee’ in the video.

Extra thanks: Becky Ramotowski and for the photos. The photos from Garden Safari are ©