I just had to comment on one news story I just read. Apparently New York subway stoppages are frequently caused by people fainting from lack of food through excessive dieting. Having now lived in New York for two years, I can attest to the obsession many New York residents have for appearances. By comparison Australia is far more relaxed, and far more forgiving of individual dress styles. It seems this dieting fad could be inconveniencing a lot of people.
Category Archives: Observation
You spend nearly 1/3 of your life asleep. Or you should (somehow I never get there). As an insomniac (or at least social insomniac – too busy to sleep) I am regularly grumpy, headachey and very vague with lack of sleep.
Not only can I not sleep, I resent the amount of time I have to spend virtually unconscious. Think how much more I could do with an extra 6 or 7 hours a day. But lack of sleep can be dangerous (and not just from falling asleep at the wheel).
Sleep seems to be essential for humans – a time for the brain to re-organise and regroup. It plays a part in learning, memory and development. It promotes cell regrowth and restoration. Sleep may also be important in regulating temperature, with brain and body temperature fluctuating during the different stages of sleep.
Humans are not unique in their sleep – many animals (including mammals, fish and invertebrates) also sleep, but if you think about it, sleep does have serious evolutionary disadvantages. When asleep, you are vulnerable to predation and to sudden environmental changes. Senses reduce or even switch off during sleep. Even the need for smoke alarms is due to the inability of sleeping people to smell smoke. You cannot look after young whilst asleep. Sleeping for nearly a third of your life reduces the amount of food and water you can collect and reduces the time available for procreation. So any benefits come at a high cost.
So could humans reduce or remove the need for sleep?
Many animals have avoided some of the problems associated with sleep by replacing some, or all, of their sleep with unihemispheric sleep. That is, they sleep one brain hemisphere at a time. This means that they can continue to function while resting the brain. Animals which practice this type of sleep include many birds and cetaceans including dolphins. Immediately you can see the advatange. By sleeping with only a single hemisphere at a time, the other hemisphere can continue to work allowing you to fly or swim at the same time. Migratory flights are long enough without stopping every couple of hours for a nap.
Buddhist monks claim to be able to meditate with a single brain hemisphere at a time. If we could all learn to do this, could we gain the ability to turn off one hemisphere while using the other?
Sleep consists of two distinct types. REM (rapid eye movement) sleep – a small proportion of sleep time in which the brain appears aroused – and non REM sleep which is characterised by desynchronous brain activity. Non REM sleep is the type of sleep animals can do unihemispherically. However, it appears that animals can only undergo REM sleep with both hemispheres. Humans spend 20 – 25% of their sleep time in REM sleep. This suggests that not all sleep could be replaced even if we could isolate brain hemispheres. But even reducing the hours of sleep by 80% would be of benefit.
Another possibility is transcranial magnetic stimulation (TMS). This creates small electrical currents in the brains of volunteers. Drs Stern and Lisanby of Columbia University have used TMS to stimulate the brains of people who have been deprived of a night of sleep. Volunteers given TMS performed better on tricky problems than their equally sleep-deprived but not stimulated peers. Furthermore, they could refuse the lure of a darkened room and remain awake longer. Perhaps in the future, electrical stimulation will have the power to “reset” the brain, reducing or even eliminating the need for sleep.
Chemicals could also solve our needs. Stimulants such as Provigil, a drug created by Cephalon and used by the US military claims to permit people to stay alert and active for 48 hours without side effects. Other drugs aim to make sleep time more efficient by forcing the body into the most effective sleep rhythms thus reducing the total number of hours of sleep required.
Whatever the solution turns out to be, I can imagine a child of the future coming home from school and saying “Mum, did you know that hundreds of years ago people spent 8 hours a day unconscious? How did they get anything done?”
Caldwell J.A. (2001) Efficacy of stimulants for fatigue management: the effects of Provigil(R) and Dexedrine(R) on sleep-deprived aviators, Transportation Research, Part F, Traffic Psychology and Behaviour, 4(1):19-37
Marks G, Shaffery J, Oksenberg A, Speciale S, Roffwarg H (1995). “A functional role for REM sleep in brain maturation.”. Behav Brain Res 69: 1-11.
Rattenborg NC, Amlaner CJ, Lima SL. (2000) Behavioral, neurophysiological and evolutionary perspectives on unihemispheric sleep. Neurosci Biobehav Rev. 24(8):817-42.
I have noticed that babies and small children often sleep with their eyes open. I therefor wonder if sleeping with one’s eyes closed is a sleep requirement or rather a learned behaviour – how often as a child were you told to “close your eyes and go to sleep”? Apart from protecting eyes with eyelids, does closing one’s eyes provide any benefit?
Going to a religious service may be healthy for the spirit, but it could prove hazardous to the body.
Church incense adds to the mood and mystery of a service, but it also produces a large quantity of airborne particles. While this is particularly true in Eastern religions incense also is an important part of the service in many orthodox and “high” Christian religions (such as Catholic, Anglican and Russian Orthodox).
So how dangerous could breathing this level of pollutants be?
For the average churchgoer who only spends a couple of hours a month in church, the risks are probably very low. But for those whose religious professions require many hours a day in such a smokey atmosphere, these risks can add up.
Incense is made of a mix of scented resins, spices, herbs and oils. It is deliberately designed to smoke as it burns. This means that the carbon molecules making up the plant material constituents do not fully combust (combine with oxygen to make carbon dioxide – CO2). This leads to the production not only of carbon monoxide (CO) but also small particles which become suspended in the air of the church or temple. With poor ventilation, the concentration of particles in the hall can build up over time, and produce that scented, smokey haze.
Along with the larger particles, there are other molecules produced by the burning incense. These are potentially even more hazardous. Many belong to the family of polycyclic aromatic hydrocarbons (PAHs) and these include naphthalene (moth balls) and a collection of other compounds, many of which are included in warnings of exhaust emissions and soil toxicity. These PAHs are known carcinogens and are also indicated in hormone system interference and in immune system damage.
If you look at places where solid fuel (such as wood) is still burnt inside the home to provide heat and cooking facilities, you can begin to see how dangerous such smoke is. World wide, indoor smoke is linked to acute respiratory infections, middle ear infection, chronic obstructive pulmonary disease (COPD), asthma, cancer, tuberculosis, and eye diseases causing blindness. Indeed it is such a big issue that conservative estimates put world deaths in 2000 due to indoor smoke risks at between 1.5 and 2 million deaths.
Certainly studies carried out in Taiwanese temples have shown an increase in respiratory illness in workers heavily exposed to incense burning.
I also wonder whether the chemical mix works as a mild hallucinogenic. Carbon monoxide and dioxide can make people feel sleepy and a little euphoric. Similarly, some chemicals from the class of PAHs can cause hallucinogenic states. Perhaps incense also affects mood and consciousness as well. Thus people who feel good after a church service may be responding to more than just the preacher’s message.
Ezzati M and Kammen DM, (2002) The health impacts of exposure to indoor air pollution from solid fuels in developing countries: knowledge, gaps, and data needs, Environ Health Perspect, 110(11): 1057–1068.
Ho CK, Tseng WR, Yang CY. (2005) Adverse respiratory and irritant health effects in temple workers in Taiwan, J Toxicol Environ Health A. 68(17-18):1465-70
Lin TC, Chang FH, Hsieh JH, Chao HR and Chao MR (2002) Characteristics of polycyclic aromatic hydrocarbons and total suspended particulate in indoor and outdoor atmosphere of a Taiwanese temple, J Hazard Mater. 95(1-2):1-12.
Lung SC, Kao MC and Hu SC (2003) Contribution of incense burning to indoor PM10 and particle-bound polycyclic aromatic hydrocarbons under two ventilation conditions. Indoor Air. 13(2):194-9.
Weber, S (2006) Exposure of churchgoers to airborne particles, Environ Sci Technol. 40(17):5251-6.
On a regular surface (say a rose petal), water bonds to the surface and spreads out until the forces within the water holds it in check. On a very clean sheet of glass, the bonding between water and glass will create a very thin film. On other surfaces, the drop will be pulled into a rounded shape as bonding between surface and water will not be strong enough to overcome the cohesive power of hydrogen bonds in water at the edges. If you look at water on a rose petal, it will be curved on the top and sides, and flat on the bottom where it touches the petal.
New materials are being created that are ultrahydrophobic. This means that they repel water (ultra – very, hydro – water, phobic – against). They can be made by creating a surface covered with tiny “hairs” on the nano-scale. When water hits the surface, it can’t bond as it is not truly a surface. You can imagine the water balancing on a single hair – the attraction between water and the tiny surface area of the end of the hair is not enough to overcome the cohesion of the water drop. Below is a photo I took of water on an ultrahydrophobic surface at the laboratory of Dr Arthur Epstein at Ohio State University. Note that water forms an almost perfect sphere (as there is no bonding to the surface). This means that water will run straight off the material. Not only useful for weather proofing, this type of material can be used to create self-cleaning fabrics and bulidings – where dirt literally can’t stick.
Some plants use this method to prevent water sticking too long to their leaves and drowning them.
Car manufacturers spend millions on streamlining cars for lower air resistence. But what is the most efficient shape for a car to be?
Look at water droplets travelling through air. As a liquid, surface tension keeps the molecules together as a drop. In a vacuum, water drops are spherical as surface tension forces minimise the surface area. Travelling through air, water takes on the characteristic tear-drop shape – air resistance flattens the front while forming a streamlined “tail” at the rear.
Liquids will take the shape created by the combination of the forces acting on it (eg. the edges and base of a glass combined with gravity). Thus a teardrop shape is probably the most efficient shape for an object to take while travelling through air. Similarly this should hold for submarines travelling through water.
Indeed dolphins and whales seem to be shaped a little like this as well – a large bulbous head tapering to a thinner tail.
Perhaps in the future, as fuel becomes more scarce and thus air resistance issues become more important for greater fuel efficiency, cars may look more like this as well.
I love illusion and “magic”. Perhaps this is because my mother used to be a magician’s assistant.
I once talked to a magician (family friend) about different types of audiences. Apparently illusions fall rather flat if your audience consists of young children (under the age of about 5). Show them a coin and make it disappear and they are not amazed. In fact they just seem to file the information away under “sometimes coins just vanish” (looking at my bank account I could also be persuaded of this).
It appears that children may use observation to learn basic science facts. So some of that annoying infant/toddler behaviour might just be scientific experimentation.
Perhaps babies who continually throw their posessions out of the stroller are not just being difficult, they are repeating experiments demonstrating the power of gravity. Similarly toddlers splashing spoons into food may be exploring the differences between solids and liquids.
I don’t know of any studies looking at child development in terms of physics knowledge but it’s an interesting observation.