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Monday, 23 February 2015

Are Nanomaterials Toxic?

There's a lot of concern about the potential toxicity of nanomaterials, intensified by the absence of regulatory standards. This means they aren’t currently required to be safety tested before being used in commercial products. So are nanomaterials toxic, what limits our understanding and how big are the risks to our health?

What are nanomaterials?


Nanomaterials are defined purely in terms of size - they are between 1 and 100 nm in at least one dimension. 1 nm is one millionth of a mm in length, and may be occupied by as few as three atoms, depending on their kind. Nanomaterials can be sheets, wires, rods, particles or platelets, and can be made of any material and have any other properties. Natural nanomaterials include spiders' silk and cotton, and manufactured nanomaterials include carbon nanotubes, metal and metal oxide particles and soots. They occur in paints, fabrics and cosmetics, food packaging and drug delivery medicines. More than a dozen new consumer products containing nanomaterials enter the market every month[1].

Sunday, 15 February 2015

TWDK Receives All Star Award For User Engagement

Constant Contact logo
TWDK Receives 2014 Constant Contact All Star Award
Recognized for achievements using online marketing tools to drive success

[London, UK][12 Feb 2015] — Science education and communications organisation Things We Don't Know C.I.C. has been named a 2014 All Star Award winner by Constant Contact®, Inc., the trusted marketing advisor to more than 600,000 small organizations worldwide. The award, given annually to the top 10% of Constant Contact’s international customer base, recognizes these select businesses and nonprofits for their significant achievements leveraging online marketing tools to engage their customer base and drive success for their organization. TWDK is one such exemplary organization.

Since 2012, TWDK has helped scientists from across the UK, USA, Europe and Australia to explain the problems they're working on in simple, understandable language. By explaining the things we don't know or understand, how we know there's a problem with our current knowledge and why we haven't been able to answer it already, TWDK aims to improve the public understanding of and engagement with science.

We’re delighted to be recognized by Constant Contact for the way in which we engage with our users, said Ed Trollope, TWDK's founder and CEO. We strive to offer the maximum flexibility for users who wish to be notified of our latest updates - we don't want to send you emails you'd rather not get, and Constant Contact provides an easy way for our users to decide which notifications they wish to receive.

Friday, 6 February 2015

How big are atoms?

You may have heard someone mention the size of atoms, in the media or at school perhaps, and you’ll certainly have heard people talk about how small atoms are. So you may be surprised to hear that we don’t know how big atoms are - not exactly, only approximately. But why not?

There are two main problems with measuring the size of atoms - other than the fact that they’re definitely too small to measure by eye, even through a microscope:
  • Atoms don’t have defined edges
  • Atoms can change their size and shape

Atoms don’t have defined edges


We normally talk about electrons in “atomic shells”, which gives the impression of hard, discrete surfaces, like the kernel of a nut. Sometimes, instead, we say electrons travel in “orbitals”. But this conjures up an image of planetary orbitals - specific lines that electrons are restricted to, like a running track. This isn’t a good model. A better description of electrons around a nucleus is “electron clouds”. These clouds describe fuzzy areas of electron density with difficult-to-determine edges. Electron density is the same as negative charge if you assume an electron is a goo smeared out like a cloud, rather than a particle which inhabits a distinct space. This is exactly what an atom is like. We have a fancy name for it: electron density probability distributions.

Monday, 19 January 2015

Alzheimer's disease - the causes and consequences

Alzheimer’s disease is the most common form of dementia and affects almost half a million people in the UK alone - and the number is rising[1]. Typical symptoms of Alzheimer’s include lapses in memory, mood swings, and difficulties performing everyday activities[1], but the exact symptoms a patient will display are unique to the individual. The only thing that is consistent between all Alzheimer’s patients is the debilitating effects this disease has on the patient and their quality of life. Many patients suffer from extreme memory loss, losing the ability to recognise friends and loved ones. Some patients even lose the ability to feed themselves and rely on carers and family members for basic life skills that we take for granted.

Despite being identified in the early 20th century, we are still not exactly certain why some of us will develop Alzheimer’s while others will not. Our brains are complex organs that provide us with memories, personalities and make each individual unique; any disease that affects this vital organ can lead to drastic changes in someone’s life. Alzheimer’s is no different; it’s a progressive disease meaning the damage to the brain worsens over time, leading to more pronounced symptoms and deterioration in a patient’s condition[1].

Photograph of Auguste Deter, the first patient to be diagnosed with Alzheimer's Disease
Auguste Deter was the first person to be diagnosed with Alzheimer’s disease, in 1901. She died in 1906, aged 55. Photograph by unknown photographer, 1902. (Public domain)

There are many aspects of Alzheimer’s that makes finding a cause, and indeed a cure, more difficult. For example, Alzheimer’s is unique to each individual patient depending on which part of the brain is affected. There are many different types of dementia, of which Alzheimers is only one, and differentiating between them is difficult because the symptoms are similar and can be very vague in the early stages, and similar to other conditions such as depression. We’re currently able to diagnose Alzheimer’s with 90% accuracy; it’s impossible to achieve 100% without dissecting the brain itself [2], although other diagnosis methods are rapidly catching up!

Saturday, 17 January 2015

Easy fundraising

Happy New Year from the team here at TWDK! We hope you're looking forward to 2015 as much as we are.

We wanted to start the new year with a THANK YOU to all our supporters. We really appreciate the fact you're just reading our articles, let alone sharing it and even voting for us in competitions! We've been really blown away by the level of support we've seen in 2014.

Thank you from TWDK. Photograph of two people shaking hands.
You're all awesome, and we do what we do just for you.

And now we've got a simple way you can help support us each time you shop online, simply and easily - and for free :)

We've teamed up with fundraising for good causes website easyfundraising, so that each time you shop online we receive cash donations from the retailers, and it costs you nothing. Just visit their site first to register, then either use their links to visit the retailers or (optionally) install a toolbar that displays a "click here to activate donations" option when you visit one of the 2,700 sites that participate. Personally, I love the toolbar.

Happy shopping!

Friday, 5 December 2014

Collapsing Ice Shelves

In 2002 the Larsen B Ice Shelf on Antarctica collapsed spectacularly. An area of ice twice the size of Greater London was lost in less than a month. This occurred in the northernmost region of Antarctica - the Peninsula - which has warmed-up by more than five times the global average over the last century[1]. A result of this is that, in certain parts of the Peninsula, the surface of the ice is starting to melt. The water from this melting can accumulate to form lakes up to 4km long. Larsen B was covered in these lakes, but just before the ice shelf collapsed these lakes started to drain. First one drained, then those around it, then those around them in a chain reaction that is suggested to have been key to the sudden collapse of the ice shelf[2].

Photograph of Larsen B ice shelf collapse in February 2002 by NASA MODIS
In February 2002, satellite images of the area stunned scientists as they watched 3,250 square kilometers of ice sheet disintegrate within the space of a month. By the end of 2006 the Larsen A and B glaciers were losing 22-40 billion tonnes of ice per year. Image credit: MODIS, NASA's Earth Observatory (CC-BY 2.0)

We don’t know what caused the lakes to drain so suddenly, or exactly how this links to the ice shelf’s collapse. Various hypotheses have been suggested as triggering the collapse; including the forces that the weight of the lakes exert on the ice shelf[2], and the melting of the ice shelf from below by heating from the ocean[3]. However, it is clear from the sudden drainage of the lakes that their role needs investigation, especially as they are beginning to appear further south on the Antarctic Peninsula.

Thursday, 20 November 2014

A Swift glance at red dwarfs

November 20, 2014 is a huge day for NASA’s Swift spacecraft, as it marks the tenth anniversary of its launch. Currently orbiting our planet, Swift is scanning the skies for potential sources of events known as Gamma-ray bursts (GRB’s). Each burst is a huge, but relatively brief, flash of very high energy radiation coming from interstellar space. Astronomers believe they happen fairly frequently (we detect around one per day according to NASA), and last from a few milliseconds up to a few minutes. Swift’s role is to detect these events using the Burst Alert Telescope (BAT), in order to find out what exactly is causing them. This telescope has a very wide angle lens, which can see about a sixth of the sky at any one time – about the same as one of our eyes can see - and scans around 88% of the entire sky each day[1].

Gamma-ray bursts can happen at any moment, so Dr Kim Page and her team at the UK Swift Science data centre (UKSSDC) based in the University of Leicester take turns to be ‘on-call’ for when BAT is triggered. There are two ways BAT can be provoked into action; by a quick rapid spike in high-energy waves or by a cumulative increase in a particular part of the sky over a longer period of time. These two mechanisms are known as the “rate trigger” and “image trigger” respectively, named for the specific way in which they pick up radiation. If the telescope is triggered it sends a message to the various cameras onboard Swift to “switch on”, which then turn and face the area of sky from where the original signal was first detected. At the same time, it sends an automated SMS to the on-call team members at the UKSSDC, whilst also writing each team member an email containing the relevant data about the location, time and intensity of the trigger source. The X-ray, UV and optical cameras on Swift can then investigate the radiation burst further. The Swift team have found this to be extremely effective and usually the phenomenal increase in energy has a Gamma-ray burst at the centre. But, as we will see, this is not always the case.

Artist's impression of the NASA Swift spacecraft
The Swift spacecraft has been orbiting the Earth since 2004, collecting data about the locations of over 800 gamma-ray bursts; extremely high energy events which occur deep in space. From understanding more about the causes and nature of GRB’s, astronomers hope to understand the early universe better. Image credit: NASA E/PO, Sonoma State University/Aurore Simonnet

Occasionally, an event which isn’t a GRB will cause the detectors to swing round and peer into the depths of space. On April 23, 2014, BAT picked up a huge influx of energy coming from a small constellation known as Canes Venatici (part of the Ursa Major group). The image trigger alerted Dr Page with a text message at around 10pm, telling her and her team that there was a potential GRB in this constellation. Within two minutes the Swift cameras had collected as much data about the position of the source as they could. This data was then cross-referenced with catalogues of stars and galaxies, to see if this patch of sky had produced GRB candidates on previous occasions - making it more likely to be a “false positive”. As a matter of fact it had – and the team found that the patch of sky they were looking at contained a binary red dwarf system, about 60 light years away. So, by then we knew what was setting BAT off, says Dr Page, Red dwarf stars are well known for their highly energetic flares. But the fact that this system could be expected to produce powerful flares didn’t prepare Dr Page and her team for the sheer enormity of the flares they were seeing this time.

Tuesday, 11 November 2014

Comet Chemistry

Dirty snowballs, snowy dirtballs and the leftovers of solar system formation. These names are commonly used to describe the often visually stunning ice extravaganzas that streak across our skies from time to time - comets. These somewhat simplistic names mask the importance of comets as repositories for material from which the planets formed. Comets contain volatile chemicals - materials that vapourize at relatively low temperatures, such as water, carbon dioxide, ammonia, and methane. This means comets have very limited lifetimes - they get vapourized and lose a lot of their mass each time they pass close to the Sun - so we know that each one we see is relatively new to the inner solar system, giving astronomers a window through which to observe the elemental and isotopic evolution of the early solar system.

The Sun emits light across much of the spectrum, from the blues, greens and reds we can see down into the infrared and up into the ultraviolet. When that light reaches an object, like a comet, some wavelengths of light get absorbed while others are reflected, depending on which materials are present. Similarly, certain molecular interactions also emit light but only at certain wavelengths. This leads to the creation of “spectral lines”. However, even the Sun’s spectrum contains thousands of absorption lines, known as the Frauenhofer lines.

Comparison of images for the continuous electromagnetic spectrum, emission and absorption spectral lines, and the solar spectrum.
Different elements and chemicals absorb and emit light at different wavelengths, so by analysing these spectral lines we can determine which materials are present. (Public domain image)

Current methods for determining the composition of a comet from the relative comfort of the Earth rely on the analysis of these spectral lines, but this approach is hampered in a number of ways. Firstly, there is the problem of the sheer number of spectral lines detected, and the superposition of these lines in relation to one another. Identifying the distribution of one molecule amongst the thousands of lines that can be detected in one observation is a complex and difficult process. This can also limit the detection of rarer chemicals as they can be masked by more prevalent compounds. Interference from the Earth's atmosphere is also an issue when ground based telescopes are used. The atmosphere can absorb photons at a number of different wavelengths, so some lines of certain species (molecular oxygen and water for example) are not detected at all.

On top of all this, as a fast moving object hurtling towards the Sun, the only volatiles available to study are those located in the comet's coma - the cloud of gas surrounding the solid ‘nucleus’ of a comet. The composition of the coma is assumed to be different from that of the nucleus because the volatile elements vapourize more quickly, so the coma is expected to have more of them and may not reveal some non-volatile elements present in the nucleus. As the relationship between the chemicals observed in the coma and those contained in the nucleus is unknown, abundances in the protoplanetary disk that seeded our solar system cannot be accurately inferred either.

Annotated photograph of comet 103P Hartley 2. Copyright Nick Howes.
Annotated photograph of Comet Hartley 2, showing the solid nucleus in the centre, the gaseous coma surrounding it, and a faint tail. Comet 103P Hartley was once described as a weird little comet by NASA, due to its high levels of activity.
Photograph ©Nick Howes, used with permission. All rights reserved.

At present, knowledge of a comet's interior is limited mostly to theoretical models. Models suggest that comets are composed of a non-volatile component, usually referred to as dust, and a volatile one consisting of ice[1]. To date, only two comets have been comparatively well studied; Halley's comet from its 1986 sojourn around the solar system and comet Tempel 1. Comet Tempel-1 was the main focus of the successful NASA Deep Impact mission which provided the first opportunity to look inside a comet.