Scientific Scribbles

The voice of UniMelb Science Communication students

The architecture of sleep

Andrew’s post about segmented sleep patterns reminded me of a documentary I saw a while ago. It was about the Pirahã people, an indigenous hunter-gatherer tribe living in the Amazon Rainforest following a similar pattern of multiple short naps throughout the day. I read some more about sleep research which I’m reviewing in this post and relating to my own experience.

I bought a sleep phase alarm clock some years ago. The alarm clock measures my movement at night with a wristband sensor and tries to wake me up during a light sleep phase. This means the alarm goes off up to half an hour before the time I set it to but it does so with the very pleasant sound of tweeting birds. Gone are the times when I was woken up by a horrible noise, provoking the urge to smash that alarm clock.

Convenient as it is, the sleep phase alarm clock does not make up for a lack of sleep. I think one of the main reasons I feel more refreshed in the mornings these days is that I am more aware of my sleep cycles. I always try to set my alarm to a wake up time which is a multiple of 90 minutes, the length of an average sleep cycle. There are 3 stages of non-REM (Rapid Eye Movement) sleep. Stage one is the transition to sleep and lasts about 5 minutes. In the second stage, lasting 10 to 25 minutes, heart rate and body temperature decrease. The third stage is deep sleep. It’s difficult to wake up people in that phase and when woken up they usually feel disoriented for several minutes. Blood flow to muscles is increased to restore physical energy. The REM sleep phase is first entered about 70 to 90 minutes after falling asleep. In this phase arm and leg muscles are paralyzed and most dreaming occurs then. However, this paralysis does not occur for some people and can lead to sleep behaviour disorders like sleepwalking. During a good night’s sleep (or two sleeps, for that matter) we go back and forth through these stages in cycles. Usually deep sleep occurs in the first half of the night. In the second half, REM stages are longer and we don’t go to the third stage anymore. This explains a sensitivity to waking up in the middle of the night or early morning hours, because that’s when we stay in the lighter sleep phases.

My alarm clock records the measurements and below is a diagram of my movements throughout the night of August 2nd. It shows how I started moving more and more towards the morning, indicating alternation between the REM stage and light sleep first and second stages.

Yellow and green bars show movements per minute during small time intervals.

Well, I think it’s time to get some rest. It will help me concentrate and remember tomorrow.

For more information see this article about sleeping habits and this google talk by one of the pioneers in the area, Dr. William Dement or check these 40 facts about sleep for a quick peek.

Remembering a Fine Man and a Brilliant Scientist: The Inspiring Legacy of Richard Feynman

Firstly I would like to offer my sincere apologies for the above pun. Secondly… Richard Feynman!

Accessed from wikipeida commons, originally sourced from Fermilab:
Richard Feynman at Fermilab (Public Domain), Accessed from wikipeida commons, originally sourced from Fermilab:

I recently read Feynman’s autobiographical Surely You’re Joking, Mr. Feynman which is a collection of conversationally delivered anecdotes providing a wonderful impression of a truly unique individual.

So, who was Richard Feynman?

For those of you who are unfamiliar with the name, Richard Feynman (1918-1988) was a theoretical physicist who is commonly regarded as one of the most brilliant of the 20th century. Throughout his life he made substantial contributions to the fields of quantum electro dynamics (for which he was awarded the Nobel Prize in Physics in 1965), super fluidity (a phenomenon where fluids at extremely low temperatures exhibit no viscosity!) and particle physics in addition to working on the Manhattan Project which, ethical complications aside, was a vast intellectual undertaking.

That’s all well and good, but what relevance does Feynman hold for the non-physicist?

Well, Feynman stands out from the crowd of high achieving scientists due to his unique and eccentric personality, and most importantly his ability to passionately communicate scientific principles and ways of thinking to lay-audiences.

Feynman came from humble beginnings, and possessed a knack for problem solving from an early age. He made a small income as a boy by fixing broken radios of the neighbourhood simply “by thinking”! Richard’s father, a uniform salesman, played a pivotal role in nurturing and encouraging Richard’s curiosity, scepticism and imagination, three attributes that are essential for any scientist. Here is a great clip of Feynman talking about his father: Wouldn’t it be wonderful if all parents nurtured their children this way!

Throughout high school Richard made a habit of teaching himself a variety of maths, including trigonometry, algebra and calculus, keeping organised notes on each topic for easy reference. By teaching himself, Richard found he had a “different set of tools” to most other aspiring and practicing physicists who had all been taught the same methods through various institutions, and hence was often at a great advantage when tackling problems.

Feynman had an acute ability to devote himself to a single problem until he either had an answer or had exhausted all avenues of thought. This devotion led to many of his great breakthroughs.

Feynman never took anybody’s word as gospel, no matter how established they were. Whilst working on the Manhattan Project as a young man with a freshly awarded PhD, he would argue endlessly with Hans Bethe, who was 12 years his senior and highly regarded at the time, exclaiming “no, no you’re wrong” and “you’re crazy” whenever he doubted Bethe. Their relationship proved highly productive. Disagreement and debate are essential to the progress of science!

Feynman's ID badge photo from Los Alamos National Laboratory, research lab for the Manhattan Project (Public Domain: From Wikipedia Commons)

Finally, Richard Feynman had a natural ability to express his passion for science. It’s hard not to feel inspired by this clip of him talking about light:

I think we would all benefit greatly in our mission to communicate science if we could capture even a small fraction of the passion that Feynman radiated so effortlessly.

Richard Feynman’s life embodied the highest ideals of science. His undying commitment to investigating the natural world as it really is can inspire people from all walks of life and allow us to revel in the “inconceivable nature of nature.”

For further information on the exciting and inspiring life of Feynman I highly recommend Surely You’re Joking, Mr. Feynman and, for a more detailed look as the science of Feynman, Lawrence Krauss’ biography Quantum Man is excellent.

All quotes in this post are taken from Surely You’re Joking, Mr. Feynman bar the last which comes from the second linked video. (Excuse the picture alignment and runaway italics, they are corrected on my end  but not on the wall!)

The Pink Olympics

The ongoing London Olympic game might have captured more attentions from girls than the pervious ones, as its theme color is vibrant pink! One of the hottest colors of the 2012 fashion trend. Pink has penetrated its way into all levels of the Olympics, from the official logo to the sidelines of sports courts and fields. It adds warmth and comforting feelings to the very competitive atmosphere. However some people suggest that this eye-catching color does not even exist! The color pink is a band of wavelengths that mix red and violet, and it should be even called “minus green”, as it is the left overs of white light when green is taken out.

The famous American radio host, Robert Krulwich, once in his blog posted that pink doesn’t occupy a slot in the familiar colors of the rainbow- it is just a figment of people’s imagination. He cited an animated video made by the Minute Physics team to back up his theory. In this video, the physicist explained it as “ If you try to roll up the rainbow to make a color wheel, there will be a gap between red and violet…..we replace all of that hidden grandeur with pink.”, this explanation doesn’t make a lot of sense to me. I have linked this video here so you guys can check it out and may be come up with a more rational explanation.=) –> There is no pink light


Prehistoric Power Plants

Quick quiz: where and when did the first nuclear fission reactor on Earth begin to operate? If you answered Chicago Pile-1 in 1942 then you get props for good research skills or general knowledge but you’re out by almost 2 billion years. Evidence indicates that underground, around Oklo in Gabon, Africa 1.7 billion years ago, large deposits of uranium ore were undergoing fission in the same way that a modern nuclear power plant generates electricity.

Physics interlude (the best kind)! Fission reactions can only be sustained by Uranium-235 (or Plutonium-239 and a few others but we’re only interested in uranium today) which is much rarer than the heavier and useless (for fission reactions) Uranium-238. A nucleus of U-235 decays via neutron capture, splitting into two smaller nuclei and three neutrons. If any of the neutrons collides with another U-235 nucleus, it gets captured and that nucleus spits out the two smaller nuclei and three more neutrons. Rinse and repeat and if there’s enough U-235 in the uranium deposit then the reaction escalates, each time generating more neutrons. This is a chain-reaction that generates huge amounts of energy and sustains itself as long as there is a large enough density of U-235 in the reactor. 

Gabon Geology Oklo
Geology of the Oklo reactors, 1 - the reactor zones, 2 - Sandstone and sedimentary rock, 3 - Uranium ore, 4 - Granite. Licensed under Creative Commons


Rewind 1.7 billion years, deep under the soil of Africa. The uranium deposits there consisted of roughly 3% U-235 which is enough to sustain a reaction. Key to the whole event was the water that seeped through the overlying rock and dirt, permeating the whole ore deposit.  Without a medium, the x-particles would travel too quickly and bounce right off the U-235 nuclei rather than colliding and interacting. Once the reactions had been going long enough, the heat created vaporises the water and the reaction would stop until the water condensed back into liquid form and the reaction kicked off again. Scientists estimate that this on and off process continued for over a million years until there was not enough U-235 to sustain a natural chain reaction. 

These reactions are more than just a scientific curiosity. Waste products from nuclear fission are dangerous and long-lasting with potentially devastating consequences should they not be stored securely. Studies of Oklo have concluded that the nuclear waste produced there was locked into the sedimentary rock surrounding it which prevented it being exposed or dissolved up to the present day. That’s 1.7 billion years of secure waste disposal, potentially much more had we not gone rooting around in the dirt. 

I’m not going to claim that therefore nuclear power is completely safe and we should embrace it. What I will argue is that it is clearly possible to store nuclear waste safely for very long periods of time and that perhaps we can move past the scare campaigns to talk about nuclear power as a means of powering humanity’s future.

Scientific America article on Oklo

Tell Him He’s Dreaming

Like most Melbournians, over the past week I have had what can only be described as the most annoying flu ever. I often find also that when I am sick, I have some pretty interesting dreams with the latest being me fighting off a bunch of trolls at my grandmother’s house with a massive cartoon mallet. Now surely this doesn’t represent any sort of subconscious messages that my brain is trying to tell me but it did get me thinking… Why do we have dreams?

The scientific study of dreams is called oneirology. Oneirologists believe that the length of a dream can vary between just a few second to up to twenty minutes! It is also claimed that you are more likely to remember you dream if you wake up during the REM phase and as the night progresses, your dreams tend to last longer. On average, you will have around 3-5 dreams per night, but in some instances you may have more than 7. Overall, during an eight hour night sleep, you spend two hours of it dreaming.

After doing a bit of research it turns out that all dreams are often out of the control of the dreamer except for lucid dreaming where the dreamer is self-aware. I definitely wasn’t in control of that dream that’s for sure!

There are many explanations as to why we dream and how they relate (or don’t relate) to our every day lives. One of my favourites of course being Sigmund Freud. This man had some of the wackiest ideas but never quite seems to be far off the mark. His theory on dreams describes the content in two, those being manifest and latent content. Latent content is related to deep unconscious fantasies or wishes while manifest content is meaningless and superficial. It is claimed that the manifest content often overpowers the latent content.

A study was performed recently by the Journal of Personality and Social Psychology that revealed that 74% Indians, 65% South Koreans and 56% Americans believe in Freud’s dream theories. They believe that their dreams reveal meaningful hidden truths, which is quite interesting considering Freud developed his theories in the 19th century. Most of Freud’s work has also been discredited by many other scientists, but I’d like to think his ideas are more fun!

I think for now though, I’m just going to assume that being ill created some sort of chemical imbalance in my brain which caused my mind to become over stimulate and produce some interesting dreams. I guess that’s what’s going to help me sleep at night!

P.S. I found this fun interactive website about weird dreams. Enjoy!

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