Category Archives: Science

Health, Science

Do I need to drink eight glasses of water a day?

BODY HEALTH

Intro: Carrying around a bottle of water is a badge of healthy living and we’re told to drink at least 8 glasses a day – however, experts say this advice has more holes than a leaky bucket

“EXPERTS” urge us to drink water to flush out toxins and combat the effect of ageing, but like so many health myths, the 8 glasses-a-day (or 2.5 litres) advice seems to have sprung from a misunderstanding. The US Food and Nutrition Board published advice in 1945 that a “suitable allowance of water for adults is 2.5 litres daily”. Had thirsty health-seekers not gulped down this snippet straight away, they would have read the next sentence, which stated that most of this will come from food. Healthy adults, they advised correctly, had no need to drink beyond their thirst. Nevertheless, the idea stuck, and the bottled water industry pours great efforts into continuing to persuade us to drink 2.5 litres a day.

On a day-to-day basis, forcing yourself to drink that much water is unnecessary and doesn’t give credit for the body’s highly attuned ability to keep you on an even keel. Your brain’s thirst centre continuously samples the blood to make you feel thirsty before you become dehydrated. Although over-drinking is rarely dangerous in normal circumstances, drinking large amounts of water during endurance sports may dilute body salts to perilously low levels, and can even be fatal.

Studies show there’s no health benefit to drinking more than the amount we need to satisfy our thirst (except perhaps the extra exercise from more trips to the toilet!)

Doctors recommend that adults living in a temperate climate and leading a sedentary lifestyle should drink 1.5 litres of water-based drinks to make up for water lost through sweating, urination, and even the water vapour in their breath – the rest of the water you need will be obtained by eating a balanced diet.

You need to up your water intake if you’re sweating from exercise, hot weather, or if unwell with a fever, diarrhoea, or vomiting. The elderly may need encouragement to drink, because the thirst centres in their brains become sluggish in old age; similarly, young children are less aware of their thirst drive, and need to have scheduled drink breaks through the day.

WATER IN AND OUT

– Water in (typically):

. 60% of water comes from drinks

. 30% comes from food

. 10% comes from cells as a by-product of making energy

– Water out (typically):

. 60% of the water you lose is from urine

. 25% is lost as water vapour as you breathe out

. 8% is lost through sweating

. 4% is lost in your faeces

. 3% is lost through saliva, tears, mucus, and blood

– Appendage (how the body uses water)

. Should I drink until my pee is clear?

You may be familiar with the idea that the colour of your pee can tell if you are drinking enough. But don’t make the mistake of thinking that clearer is always better.

We may not know its name, but many of us are familiar with Armstrong charts from gym changing rooms or doctors’ surgeries. Named after their scientist creator, they are designed to tell you whether or not you are dehydrated by comparing the colour of your urine with yellowy-brown coloured stripes.

The chart suggests that you should drink more if your urine matches the darker stripes and stop when your pee matches the palest colours. These types of charts are very useful as an early warning of dehydration, especially in the elderly, infirm, or very young. But it’s a big mistake to think that paler is always better, and that you should drink until urine runs completely clear. By doing this, there’s a good chance that you’re putting yourself well on your way to fluid overload. If your urine is completely clear, it’s an ominous sign that your kidneys are having to work overtime to remove excess water from your system.

Totally clear urine is a signal that your body is trying to get rid of excess fluid.

– Colour Matching Guide

– It’s healthiest for your pee to match the colours of the second or third colours down from the top of this chart (i.e. a pale straw yellow or translucent yellow).

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Climate Change, Government, Science, Technology, United States

Nuclear fusion: A breakthrough that will lead to clean energy?

NUCLEAR FUSION

A REVOLUTIONARY scientific breakthrough is thought to have brought humanity a step closer towards limitless clean energy from nuclear fusion.

Since the 1950s, scientists and researchers have been working tirelessly towards the “holy grail” of creating more energy from nuclear fusion than they put in.

Now US government scientists in California have reportedly done it, by aiming the world’s largest laser at a nuclear target the size of a peppercorn.

The result, from a nuclear reaction reaching three million degrees Celsius, is apparently 2.5 megajoules of energy, from 2.1 megajoules of laser energy.

Nuclear fusion is preferable to nuclear fission, which is currently used to power the planet alongside fossil fuels and renewable power.

That is because nuclear fission splits heavy atoms like uranium or plutonium, to create energy, producing potentially dangerous radioactive waste that must be stored.

Nuclear fusion creates energy by bringing atoms together, instead of splitting them, and has no waste products, making it clean energy.

Unlike coal, the supply is limitless, usually requiring just two materials called deuterium and tritium, which are slightly different versions of hydrogen and found in sea water and mineral springs.

A small cup of this fuel could one day be used to power a house for hundreds of years.

The breakthrough at the federal Lawrence Livermore Laboratory in California was achieved using a laser pulse amplified a quadrillion (a million billion) times and split into 192 different pulses.

These enter a hohlraum – a gold container – and hit a tiny capsule of deuterium and tritium, creating shockwaves which produce vast amounts of  energy, in a process called inertial confinement fusion.

Significant engineering challenges remain, including how to cut the cost of nuclear fusion, harness the energy produced, run it through a turbine and get it into the National Grid.

Most experts believe this won’t be possible until 2045, but some say it could be done in a decade and is likely to be achieved using a different type of nuclear fusion called magnetic fusion.

But whether it is using magnets or lasers, the experts agree it is the main hope for escaping the climate crisis.

Sir Robin Grimes, professor of material physics at Imperial College London, said: “This is a key step towards commercial fusion – the technology which will ensure our survival on Earth, providing enough energy, with a low impact on the environment, to hugely reduce our contribution to climate change.”

Jeremy Chittenden, professor of plasma physics at Imperial, said: “If what has been reported is true and more energy has been released than was used to produce the plasma, that is a true breakthrough moment.”

Nuclear fusion, if it can be scaled up and made to run more continuously, could in future be almost zero-carbon.

However, some experts point out that the amount of energy used for the entire system containing the laser means, technically, scientists are unlikely to have yet produced more energy from nuclear fusion than was put into it.

The US energy secretary, Jennifer Granholm, made the announcement of a “major scientific breakthrough”.

– Diagrammatic representation of how nuclear fusion works. Source: BBC

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Science, Society

Can I learn to be better at multitasking?

MULTITASKING

Intro: It’s time to nail this myth once and for all – the scientific fact is that your brain is simply not wired for multitasking

WE make the mistake of thinking that our grey matter is like a computer – but try as we may, our conscious thinking powers cannot be split along separate paths in the way that a computer can run multiple programs simultaneously.

It takes between a few milliseconds to several minutes for the brain to fully orientate to a new task, depending on the task’s complexity. When we dart like a butterfly beween tasks, the vast majority of us end up not doing any of them well: we make more mistakes, and become less able to remember new things. By continually switching focus – and maybe buzzing on stress-induced adrenaline – we can be blind to how unproductive we’re being. Those who think they’re experts at multitasking are actually the worst at it, thanks to the Dunning-Kruger effect. This is the human curse of exaggerarting our own abilities and no one is immune. The only way to gain a realistic insight into your skills is to be independently assessed.

To work with, not against, your brain, prioritise tasks so you know what needs to get done first, cut those email notifications, and avoid starting a job until you’ve prepared what you need to complete it.

SUPERTASKERS

A plucky 2.5% of us take multitasking to the next level: these supertaskers are, for example, able to take charge of a hospital Accident & Emergency Department, and not be fazed by a ward full of patients in pain, a crowd of relatives clamouring for attention, and another ambulance due to arrive in the next five minutes.

Somehow, the decision-making cabling in the supertasker’s brain is able to fire with great efficiency – doing more work with less effort. Supertasker’s can filter out unwanted distractions, remember details easily, and stay as cool as a cucumber when under extreme pressure.

You might wish you were one of this elite breed, but it seems to be impossible to learn these skills – being a supertasker may simply be down to your genetic “dice” rolling a double six.

CONCENTRATION

Complimentary to this topic is the issue of concentration and scientists have been thorough in their research in addressing the oft quoted question, ‘Will listening to music improve my concentration?’

Listening to music certainly nudges the brain during tedious work, but it remains a myth that listening to classical music will make you smarter.

First coined in 1991, the “Mozart Effect” became a craze among parents and students after a series of short experiments showed that some students performed slightly better in certain types of tests when taken shortly after a music lesson or listening to classical music. Newspapers and the media loved the story, whipping up these findings into “listening to Mozart makes you smarter” – which was a bold stretch of the imagination.

Since then, further research has shown that while background music does give a slight boost to spatial reasoning (the ability to imagine and answer questions about 2D and 3D objects), it doesn’t improve your score in IQ or academic tests. Even then, the improvement doesn’t last long, and the music doesn’t even need to be classical – any pleasant background sound helps you stay focused, and lively pop and rock tunes tend to come out best of all. So if you are undertaking spatial reasoning tasks such as repairing a gadget, map-reading, or video gaming, put on your favourite upbeat track.

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