Snell’s Window

underwater mark tipple

When you are under water and you look upwards, you see everything above the surface of the water through a round window of light. I think we are so used to this phenomenon, if not from experience then at least from films, that we don’t think about it. At least I didn’t until I saw Neil Gower’s beautiful drawing for the cover of the Watermarks anthology.


The round window of light is known as Snell’s Window and is to do with refraction of the light as it travels from the air to the water. The area outside of the cone of light that forms the window will be completely dark or will reflect objects within the water. It sounds complicated, and in terms of physics it is, but a photograph taken from under the water reminds us how familiar the effect is even if, like me, you don’t fully understand it.

Art work for Watermarks by Neil Gower, underwater photograph by Mark Tipple



Face in the water


Many people tell me before they come to their fist swimming lesson that they can’t put their face in the water. So far every single adult I have ever taught has been able to do it within about five minutes of arriving at the lesson. Some people have had a fear of this for years but for some reason, and with a little bit of guidance they are always able to do it. I am not sure exactly how many people I have taught but it is certainly in the hundreds.

Children are quite a different matter. They will not put their faces in the water until they are ready for it. This may take five minutes or it could take several months or longer. You absolutely cannot persuade a reluctant child to do it if they don’t want to. This is one of the main ways in which teaching children differs from teaching adults.

To learn to swim you do really need to be able to put your face in the water. This is a simple matter of physics. Our bodies are less dense than water, but only slightly. That means that most people float (there are some very rare exceptions). But any part of the body that is held out of the water is heavy. This means that you cannot float without doing something. If your head is out of the water you have to move your arms or legs to keep you afloat. If your face is in the water you don’t have to do anything.

It takes time to learn what the resistance of the water feels like, how to ‘catch’ the water, and how much effort you need to use to propel yourself forward, or to keep your head out of the water.  Once you have learned to swim it is easy to swim with your face out of the water, but to learn to swim this way is not impossible, but quite difficult.

As I say I have never had any problem at all persuading any adult, however scared they are, to put their face in the water. This is never a stumbling block. But there is a point where many people get stuck and that is in allowing themselves to float. Many people find it very difficult to let go and allow the water to hold them.

Swimming monkeys–apes-prefer-breaststroke.html#.Ur1nc8uYapr

Interesting to see that the chimpanzees here swim with their faces both in and out of the water. I find with many people I teach that it is the fear or reluctance to put the face in the water that stops them from swimming efficiently and effectively.


“To be weightless for the better part of a year, to never even have to lift my head
and then to have to be subjected again to my own inevitable weight having to
pick up my arm […..] It was an extremely unfair feeling”

Canadian astronaut Col chris-hadfieldChris Hadfield speaking on the Today programme, (BBC Radio 4 29th October 2013),  about how it felt to return to Earth and experience the heaviness of his own body .

Most of us will never go into space and will never experience the weightlessness Chris Hadfield is talking about here. Floating and swimming in the water is probably the closest we can get. That is why they train astronauts underwater in special zero gravity tanks.

The secret to learning anything

einstein-laughingSometimes parents say to me that they are worried that all the children are doing in my lessons is playing. I am not sure that these parents always appreciate that, especially in the water, it is through playing that the children learn. When I teach non-swimming adults the main difference between them and the children is that they don’t play in the water. It is true that sometimes the children can enjoy the lessons so much that things get very lively. Then I have to remind them of two basic rules

  • don’t jump in without asking me
  • don’t hold onto each other in the water.

These have to do with safety and are not too difficult to remember, although we do have to over them quite often. I believe that to learn any new skill properly, at any age, you have to enjoy the process. Here is a letter from Albert Einstein to his eleven year old son. It was written in 1915.

“I am very pleased that you find joy with the piano. This and carpentry are in my opinion for your age the best pursuits, better even than school. Because those are things which fit a young person such as you very well. Mainly play the things on the piano which please you, even if the teacher does not assign those. That is the way to learn the most, that when you are doing something with such enjoyment that you don’t notice that the time passes. I am sometimes so wrapped up in my work that I forget about the noon meal. . . .”

He wrote this letter just after having completed his General Theory of Relativity.

My thanks to Maria Popova for drawing my attention to this quote in her blog

Fear of flying

?????????????????????????????????????????????????????????????????????????????I have worked with many non swimmers who tell me they are afraid of putting their faces in the water.  Although it is a common fear, putting your face in the water is easy and almost everyone can do it without a problem more or less straight away. I have never, ever had anyone finish a lesson without being able, quite happily, to put their face in the water. I tell them to hum a nice song. That way their mouth is closed and the air comes out of the nose, and they are also a bit distracted. They may be afraid of seeming foolish but in the water no one can hear you anyway.

A much more persistent fear, and one that is much more difficult to let go of, is the fear of floating. It is not usually an inability to float that is the problem, that is only very, very rarely the case; rather it is the fear of being ‘untethered’ and free. We are so used to holding on in life, that to let go and float is very difficult for some people.

One woman said that it felt like the moment when you are falling asleep and you suddenly catch yourself and wake yourself up with a start. This made a lot of sense to me. Similarly in the water, you are letting go and allowing yourself to float freely and for a non swimmer this can be an unfamiliar and frightening experience, and it can feel like falling if you don’t realise that the water is there to catch you. Not everyone can overcome this fear quickly. For some people it can take a long time to let go and trust the water. This is true for children as well as adults. Sometimes people are OK as long as they have something to hold on to. One pupil could swim as long as she was holding my hand, another one was fine as long as she could touch me with one finger. But as soon as I took my hand away, even though I was not supporting her at all, she got that falling feeling and was snatched by a panicky fear .

A woman I was teaching last week  who had been rather quiet until then told me she had just come back from a Kite festival in France. It sounded so beautiful watching all the colourful kites flying high up in the sky. I told her that swimming is the closest you can come to flying in scientific terms, and it is.

Planet Earth is blue

Photo by Mark Tipple used here with kind permission.

Photo by Mark Tipple used here with kind permission.

Anyone who has been surfing or just been swimming in big breaking waves, will know the feeling of sometimes misjudging it and being tumbled over and over in the water, not knowing which way is up or down. We tend to close our eyes at these moments, but Mark Tipple kept his open and started taking  photographs of surfers under the waves. Here is a link to his website where you can see more of his beautiful photographs.

Mark Tipple’s website

‘In the water I am free’ – Swimming and rheumatoid arthritis

Bus to the pool

Bus to the pool

woman swimmingI have a good friend who is a keen swimmer and also suffers from rheumatoid arthritis. Rheumatoid Arthritis (RA) is an autoimmune disease. This means that the body reacts to some of its own cells as is they were foreign and so attacks them as it would a virus or bacteria. RA can affect many tissues and organs but it mainly attacks flexible (synovial) joints. It can be very painful and disabling and it can lead to loss of mobility and loss of function. It is not the same as osteoarthritis which tends to affect people as they get older, however both osteo and rheumatoid arthritis cause inflammation of the joints.  This can result in pain, stiffness, swelling, a decreased range of motion and fatigue. Swimming is an excellent exercise for arthritis sufferers because it provides an aerobic workout without putting strain on the joints.

There are treatments for RA but at the moment there is no cure. Scientists do not know exactly what causes it. There may be a slight genetic predisposition to getting the disease and there are a few factors that can slightly increase the risk but on the whole the onset seems fairly random.

My friend is a very active and lively person, she was fit and healthy, always out walking or riding her bike and the last person you might expect to be hit by such a disease.

We have become good friends partly through our mutual love of swimming, she swims every day, and I decided to ask her about what swimming means to her and how it has helped her deal with the RA.

I’ve always been a keen swimmer. When I was a child I had a book called ‘My Little House’. It was about a lovely house in the country and there were some children living in the house who used to swim in the river nearby, or skate on the pond in the winter. Then gradually the house became hidden under a mass of buildings and roadways and flyovers until eventually it was completely hemmed in. So they decided to move the house on the back of a truck, it was an American book, and they took it to a perfect place in the country, but I remember thinking ‘but there’s no river, no stream, no pond’. I thought ‘where is the water?’. And I’ve always had that sense that to be happy you need to be near the water.

When I was diagnosed with rheumatoid, swimming was my salvation. I said to the doctor, for whom I have a great deal of respect, ‘Will I still be able to swim properly? Will I still be able to swim a mile?’ and he said ‘We just don’t know’. But I can, I swim about a mile most days. It takes me forty minutes.

Swimming is my mental and physical escape. It is not just about the exercise, although that is important, it is cleansing and relaxing too in the deepest sense. I always go to the same pool, the local one, that I fought very hard to save from closure, before I was ill, before I knew I would need it so desperately.

The council was allowing the pool to fall in to disrepair, they wanted to sell off the land, and we had to fight long and hard to keep it open. I spent eight years campaigning against its closure and for re-investment and refurbishment and we won in the end. I am still on the safeguarding committee. We had the indoor, outdoor and learning pool re-tiled and I had to fight hard to keep the depth of the pool, it is three metres deep in some places and it would obviously been cheaper to make it a bit shallower, but I really wanted to keep the depth.

In the end I think we won the fight against closure because I managed to convince a local councillor who subsequently became the local MP and who was also a doctor, that we had to have a children’s teaching pool in the borough, that our children had to have somewhere they could learn to swim.

I go to the pool almost every day. It is crucial to me and so I fit my work around it. It is a beautiful light, long airy pool with big windows to the ground,  on three sides and an outdoor pool that is open in the summer. It is a public pool and I prefer that to exclusive private clubs. I meet like-minded people there, other swimmers, but they are from all walks of life, all ages, varying degrees of fitness. As I have said the pool has a proper deep end, also it is nice and long, thirty-three metres. I am afraid I am a bit lengthist when it comes to swimming pools.

My condition means that I can’t do much walking and no cycling, which I used to love, so the swimming is a very important exercise for me. It keeps the muscle tone, and exercises the joints, it also helps me to stretch. I have to be careful not to overdo it. My favourite stroke is front crawl but I have to limit the amount I do. I can swim on my back if I don’t push myself too hard but unfortunately breaststroke is out for me these days apart from in the sea.

There was no bus running to the pool and although I do have a car I felt that it was important that people should be able to get to the pool by bus, especially children, and I am pleased to say that after eight years of my campaigning we now also have a bus that goes directly to the pool.

I have watched children with all sorts of disabilities being taken swimming and you can see how they relax in the water. The carers and teachers have told me that the children are calmer and happier after they have been in the water.

My condition has limited my mobility in many ways but I am equal in the water, and I am free.’

Swimming, mindfulness and the Eureka moment

The story goes that Archimedes was in the bath when he shouted Eureka (I have found (it)). He realised that the volume of water he displaced getting in to the bath must be equal to the volume of the part of his body that was submerged. So, after long reflection, he had  discovered a way that the volume of irregular objects could be measured with precision. I have read that he was so delighted that he got out of the bath and rushed through the streets of Syracuse naked.

Most people recognise the phenomenon of a sudden flash of insight, the solution to a problem that you may have spent days, weeks, months or even years puzzling over.

Daniel Goleman’s book The Brain and Emotional Intelligence: New Insights is beginning to reveal what goes on in that Aha momeeurekant.

Here is Goleman in his own words.

Brain studies on creativity reveal what goes on at that “Aha!” moment when we get a sudden insight. If you measure EEG brain waves during a creative moment, it turns out there is very high gamma activity that spikes 300 milliseconds before the answer comes to us. Gamma activity indicates the binding together of neurons, as far-flung brain cells connect in a new neural network – as when a new association emerges. Immediately after that gamma spike, the new idea enters our consciousness.

This heightened activity focuses on the temporal area, a center on the side of the right neocortex. This is the same brain area that interprets metaphor and “gets” jokes. It understands the language of the unconscious what Freud called the “primary process”: the language of poems, of art, of myth. It’s the logic of dreams where anything goes and the impossible is possible.

That high gamma spike signals that the brain has a new insight. At that moment, right hemisphere cells are using these longer branches and connections to other parts of the brain. They’ve collected more information and put it together in a novel organization.

What’s the best way to mobilize this brain ability?  It’s first to concentrate intently on the goal or problem, and then relax into stage three: let go. The converse of letting go – trying to force an insight – can inadvertently stifle creative breakthrough. If you’re thinking and thinking about it, you may just be getting tenser and not coming up with fresh ways of seeing things, let alone a truly creative insight.

So to get to the next stage, you just let go. Unlike the intense focus of grappling with a problem head-on, the third stage is characterized by a high alpha rhythm, which signals mental relaxation, a state of openness, of daydreaming and drifting, where we’re more receptive to new ideas. This sets the stage for the novel connections that occur during the gamma spike.

Those moments of out-of-the-blue, spontaneous creative insights may seem to come out of nowhere. But we can assume that the same process has gone on, where there was some degree of engagement in a creative problem, and then during “down time” neural circuits make novel associations and connections. Even when creative insights seem to arise on their own, the brain may be going through the same moves as during the three classical stages.

On the other hand, I would guess that the three or four classical stages of creativity are somewhat of a useful fiction – the creative spirit is more freewheeling than that. I think the main neural action is between intense focus on the problem and then relaxing about it. And when that creative idea arrives, it’s almost certain that the brain has gone through that same heightened pitch of gamma activity that was found in the lab.

Is there a way to create the conditions whereby the gamma spike is more likely to occur? Gamma spikes normally come at random – they can’t be forced. But the mental stage can be set. The pre-work for the gamma spike includes defining the problem, then immersing yourself in it. And then you let it all go – and it’s during the let-go period that gamma spike is most likely to arise, along with that “Aha!” moment, the light bulb over the head of a cartoon figure.

There’s a physical marker we sometimes feel during a gamma spike: pleasure. With the “Aha!” comes joy. Then there’s that fourth stage, implementation, where a good idea will either sink or swim. I remember talking to the director of a huge research lab. He had about 4,000 scientists and engineers working for him. He told me, “We have a rule about a creative insight: if somebody offers a novel idea, instead of the next person who speaks shooting it down – which happens all too often in organizational life – the next person who speaks must be an ‘angel’s advocate,’ someone who says, ‘that’s a good idea and here’s why.’”

Creative ideas are like a fragile bud – they’ve got to be nurtured so they can blossom.

Daniel Goleman

As a swimmer I have for a long time counselled friends and family, and myself, to take their problems to the water. I have said before that swimming helps with all troubles. I had no real explanation for this but perhaps science is now beginning to show that if you can induce a state of mindful meditation, you can free your brain to do its own work, undisturbed by conscious, controlling thoughts. I also believe that being submerged in water adds something extra. I think it was more than a happy accident that Archimdedes was in the bath when he made his discovery.