Time out

Perhaps an unusual post but there is so much opportunity to stop, think and notice at the moment. Whether it is relaxing in a café with a cold brew or sipping a take-away in a park. There is time to slow down and ponder. Here are three points that have been puzzling recently. What do you think? Perhaps you have other things that you ponder while sitting in a café? Let me know either in the comments section below, on twitter or on Facebook.

oat milk, kone, filtering

Oat milk filtering through the Kone filter – but what does oat milk tell us about Brownian motion, molecular ‘reality’ and the nature of a scientific theory?

Molecules, the atmosphere and oat milk.

On pouring home-made oat milk into a cup of black tea, it is noticeable that a large part of the oat milk is dense and falls to the bottom of the cup (before being stirred by the turbulence in the tea). A similar phenomenon is found in the rarefaction of gases through the height of the atmosphere and in the distribution of dye in water paint. This latter effect was used to establish the existence of molecules back in 1910. The idea that Brownian motion was caused by molecules had been problematic because there was no way to see molecules in a liquid producing the Brownian motion. The theory linking the two was only developed properly in the early twentieth century. What makes a scientific theory? Is it legitimate to postulate something that cannot currently be observed experimentally?

Packing value

Why does roasted coffee often come in plastic packaging that is unrecyclable and not very reusable? What could prompt a move to a more circular economy. Would it be possible to recycle plastic bottles into coffee ‘boxes’ with an air valve at the bottle top (see pictures). This would increase the recyclability without seeming to affect the taste of the coffee?

bottle, coffee bottle, coffee box, coffee packaging

An idea for a circular economy suitable coffee packaging? Recycled plastic bottles as airtight coffee containers.

Related to that, what are your coffee values? Do you favour taste and aroma, traceability, sustainability? Does the packaging that your coffee arrives in feature? Which of these is more important to you? Does the way you drink coffee reflect this?

Footfall past a café

How many people are walking past the café you are sitting in each minute? How many does that translate to per day (accounting for differences in day/night footfall)? Assuming the paving stones remain the same, how long would it be until the successive footprints of all these people caused erosion of the pavement surface? What are the implications of this for the geological features near you?

Whatever you think about in a café or while drinking a coffee, enjoy your time taken out to think. Perhaps you will notice something (or realise something) very interesting or noteworthy and if you have any thoughts on any of the above do let me know either in the comments, on Twitter or on Facebook.


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