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Monday, 29 April 2013

Open Questions in Open Science

I sometimes tell people that "There's no point in making the biggest scientific discovery in the history of the world, if you don't tell anybody about it." In other words, science communication is important. This is why I, and Things We Don't Know, feel strongly about the topic of "Open Science". For those who aren't familiar with "open science", it's a relatively straightforward concept. The principle behind open science is that the results of science should be available to the public, free of charge. Since scientific results are published in scientific journals, this means those journals would have to be available free of charge.

But of course, there is a cost associated with the publishing of journals, so open science is not a particularly easy thing to achieve, and people have suggested several models which would make this possible - each with their own side effects and drawbacks. If you'd like to read more about the details of open science, Nature have a nice feature article which summarises the background, and another which explains the "green" and "gold" open access models.

Explaining the mysteries of science, in simple language

Friday, 19 April 2013

Why does hot water freeze faster than cold water?

This article is by our intern Freya Leask, who is also in her second year at the University of Bradford studying chemistry.

For most people, making ice-cream doesn't lead to the discovery of an unsolved mystery…unless you're Erasto Mpemba. In 1963, the then school boy stumbled across the phenomenon where initially-hot liquids sometimes freeze faster than initially-cold ones. Although this had been observed by Aristotle, this effect wasn't proved experimentally until 1969, and still isn't very well understood. Just what is the Mpemba effect, and why does it happen?

Many papers have been written about the Mpemba effect, though scientists can't even decide what that name refers to - is it the time taken to form a homogenous block of ice, or the time taken to reach 0°C? Both situations have been studied under various combinations of conditions, but either way, it seems simple enough on face value to explain. Evaporation takes in heat energy and the warmer liquid's higher rate of evaporation reduces the mass to be frozen. The initially warmer liquid also has a lower density, as the water molecules have more energy to move around more. This means more heat is released, and the liquid cools faster.

Graph of freezing rates of cooler and warmer water samples
Against all expectations, warmer water (red) can freeze before cooler water (blue) does.
Image credit: Pico Technology

Heating a liquid can also change its composition, which can affect its cooling time. For example, when salty water is heated, the water evaporates away, leaving a higher concentration of salt which lowers its freezing point and makes it take longer to cool1. However, none of these things can account for a big enough effect on the rate of cooling to completely explain the Mpemba effect.

Saturday, 13 April 2013

The beast with a billion backs: Part 2

We are not alone.

No matter how quietly you listen, nor how closely you stare you’ll not hear them, nor see them with the naked eye. They’re too small, too quiet. They are our microbiome, the trillions of microorganisms that make their homes inside and out of our bodies. They – we – are an ecosystem, with different bugs filling different niches, some helpful, some quietly parasitic, and others, well, others you do end up knowing about…

This is the second of two posts on the subject of the microbiome. The first post looked at questions around the need to unpick its importance to our health – what’s a good or bad microbiome? Which microbes are causes or effects of a disease? And how does the microbiome spread – is it like a disease? Questions which, when answered, could lead to new treatments and ways of protecting our health by manipulating this complex ecosystem within ourselves.

Collateral Damage

Whilst we can’t yet manipulate the microbiome with any finesse, we do influence it through our immune system, evolved over time to cope with invading pathogens and keep them in check. Yet when the immune system isn’t enough, we have a powerful way to, if not manipulate, then affect our microbial ecosystem; it’s just a little…inelegant and unpredictable: Antibiotics.

Photograph of antibiotic resistance tests
Two different species of bacteria with disks soaked in different antibiotics. The bacteria on the left are susceptible to all the antibiotics tested, while the bacteria on the right are resistant to most of them.
Image credit: Wikimedia commons