Category Archive: GCSE Physics

May 29 2014

Cheese Rolling – Gravitational Potential Energy to Kinetic

Cheese Rolling – Gravitational Potential Energy to Kinetic


Funny really as I always think of this as a simple topic. However, my students always find it hard, especially the formulae.

First place to start is the hill near to the village (Brockworth) where I grew up where they still do Cheese Rolling every year… Even my primary school teacher wrote a book on the topic. (However, it is not focused on the Physics!)

So now you have the idea think about a man who lifts a cheese and himself up to the top of a hill. His muscles have to do work as he is moving himself and a cheese to a point further away from the surface of the Earth. This is because the man and cheese are in the influence of a “gravitational field” which causes anything with mass to feel weight or acceleration towards the centre of the object.

So the formulae we employ to work out the work done in climbing the hill is the change in height x distance moved against the field x mass. #

We often write this as…

Ep = mgh  or sometimes as mgΔh to show “a change in height”.

So where has the energy come from…. well simple the muscles in the body of the man have contracted and converted chemical energy to movement energy to push the man away from the field.

So what happens to the energy as you release the cheese? Well we think of another idea of “kinetic energy”. As you roll down the hill and gain in velocity you exchange your gained Ep to Ek so then most of the energy is coverted according to the rule ½ mv2 .

Often we write that mgΔh = ½ mv2 so if it was a 100% transfer we could work out the maximum velocity of a cheese falling down the hill!

Try out these animations in flash to help you out…


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May 18 2014

A true sea shanty: the story behind the Longitude prize

A true sea shanty: the story behind the Longitude prize

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May 18 2014

How to treat your brain during revision time

How to treat your brain during revision time

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May 11 2014

What is Newton’s second law of motion?

What is Newton’s second law of motion?

This is a really good post to help you find out!

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Jan 27 2014

Can flywheel technology drive out the battery from car hybrids? | Corrinne Burns

Can flywheel technology drive out the battery from car hybrids? | Corrinne Burns

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Jan 11 2014

Black hole to ‘eat biggest meal’

Black hole to ‘eat biggest meal’

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Nov 30 2013

UK China nuclear deal ‘Orwellian’

UK China nuclear deal ‘Orwellian’

Security fears over ‘Orwellian’ Chinese nuclear deal

By Rob BroombyBritish Affairs Correspondent, BBC World Service

George Osborne with Chinese nuclear workers in Taishan

It was hailed by UK Chancellor George Osborne as a “new dawn” – but serious questions remain about the security implications of Britain’s nuclear energy deal with China.

The UK government has refused to say whether China’s planned investment in the British nuclear industry was approved by the National Security Council – the body that assess the risks from foreign investment in critical national infrastructure projects.

Chancellor George Osborne announced during his trip to China in October that Chinese state owned companies CGN and CNNC would be allowed to take a 40% stake in the company planning to build the Hinkley C nuclear power station in Somerset.

In the future Chinese firms could become “majority owners of a British nuclear power plant subject to British safety rules and policed by the British,” said Mr Osborne.

Tim Yeo, chairman of Parliament’s energy and climate change committee, said Britain should “warmly welcome investment from China in the nuclear industry” but said he did not know whether the National Security Council had formally discussed or approved the investment.

“It would be a great pity if on some security reason this was thrown back into jeopardy.” he told BBC Radio 4’s The World Tonight.

But other members of Mr Yeo’s committee are worried.

Conservative MP Dr Phillip Lee said it was “perverse” and “Orwellian” to allow Chinese state owned firms a role in critical infrastructure projects like nuclear power at a time when questions over Chinese cyber-attacks on the west had not been resolved.

He said future conflicts would not be about the “physical possession of nations” but would involve “control of information, control of infrastructure, water electricity and communication.”

Military links

The Chinese could not take away a nuclear power station in the event of tension between the two countries but they could “virtually switch it off” if they wanted to, he claimed.

It would also bind Britain’s hands in respect of China diplomatically, when it comes to speaking out on human rights.

On the website of the China National Nuclear Corporation – one of the companies connected to the Hinkley project – the company boasts openly of its military links.

“China National Nuclear Corporation (CNNC) is the large state-owned enterprise under the direct management of the central government. Historically, CNNC successfully developed the atomic bomb, hydrogen bomb and nuclear submarines and built the first nuclear plant in the main land of China. CNNC is the main body of the national nuclear technology industry, the core of the national strategic nuclear deterrence”.

The company website says it “shoulders the dual historical responsibility for building the national defence force, increasing the value of state assets and developing the society.”

Hinkley Point CHinkley Point C is set to take 10 years to become fully operational. It will be made up of two nuclear reactors and will be built next to Hinkley Point A and B.

Just days after George Osborne made his nuclear announcement Chinese state-run TV was showing-off its nuclear armed submarines for the first time in 42 years accompanied by rousing music.

Official Chinese news agency Xinhua called the subs an “assassin’s mace that would make adversaries tremble”.

Labour MP Dr Alan Whitehead, also a member of the energy and climate change committee called the Chinese nuclear company CNNC an “arm of the state”.

“There doesn’t appear to be a clear distinction between the role of the Chinese National Nuclear Corporation in developing civil nuclear and developing and forwarding military nuclear,” he told the World Tonight.

“Big corporations particularly national corporations in China are not companies in the way that we would see them in the UK.”

He said the Chinese military – the People’s Liberation Army – would be involved in some of the decisions made by the firm.

He has called on the UK government to state publicly how the investment in critical national infrastructure was approved and by whom.

Corruption case

Nuclear expert Mark Hibbs, of the Carnegie Endowment for International Peace, said the decision to invest in the British nuclear project would have been a “strategic decision” that would have been approved by China’s State Council – the nation’s ruling executive.

The UK Cabinet Office said in a statement that “the process for dealing with such issues falls under the aegis of the National Security Council”.

It said the government had “put in place an approach which enables it to assess the risks associated with foreign investment and develop strategies to manage them.

Cost of generating electricity, Nuclear £92.50 from 2023, onshore wind £100, offshore wind £155, tidal and wave £305, biomass £105, solar £125, electricity (gas/coal generated) £55.05, all other prices from 2014.

The National Security Council “brings together the economic and security arms of the government and is the forum that ultimately balances the risks and opportunities of inward investment decisions,” added the Cabinet Office statement.

But despite repeated requests the Cabinet Office has refused to say whether Chinese investment in Hinkley or the possible full majority ownership of nuclear reactors in the future has been formally discussed, assessed or approved by the National Security Council.

Critics fear Britain may be sleepwalking into nuclear relationship with China it will regret especially if in years to come China wants to introduce its own nuclear technology to the UK.

“The Chinese domestic nuclear programme certainly leaves much to be desired” says Dr Paul Dorfman of the University College London Energy Institute.

‘Safe power’

He is worried by the lack of transparency in the Chinese nuclear industry and cites the arrest and dismissal by the Chinese Government in August 2009 of the President of CNNC in a £260m corruption case involving allegations of “bid-rigging in nuclear power construction”.

Chinese investment in key energy infrastructure is “deeply problematic,” he said and industry experts were worried about “China’s weak regulatory structures”.

The UK Cabinet Office says Chinese firms have a “track-record in delivering safe nuclear power over the past thirty years. And that in the long-term it will deliver lower and more stable energy prices.”

“Any company involved in the UK nuclear power industry does so in accordance with the most stringent regulations in the world. On this basis, we welcome companies which can demonstrate the capability to contribute to safe nuclear power generation in the UK.”

The economics of the Hinkley C project have also been slammed. Peter Atherton of the respected city firm Liberum Capital said they were “flabbergasted” by the deal.

At £8bn per reactor, Hinkley Point is “the most expensive power station in the world (excluding hydro schemes) on a per megawatt basis,” said Mr Atherton.

He said the French and Chinese state owned firms would earn between £65bn and £80bn in dividends from British consumers over the project’s lifetime.

“The UK government was taking a massive bet that fossil fuel prices will be extremely high in the future. If that bet proves wrong then this contract will look economically insane when HPC (Hinkley Point C) commissions” added Mr Atherton.

Tim Yeo said the budget was so high “because they have factored in a much bigger contingency in to this project”.

But he added: “I do believe it is in Britain’s interests to have part of its electricity generated by nuclear power.

“It is a secure, safe, clean, low- carbon source of electricity.”

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Nov 29 2013

New Scientist News: Beer brewing could help make better bricks

Beer brewing could help make better bricks

THERE’S more to brewing than beer. A by-product of the process could be about to give an upgrade to a workhorse building material – red clay bricks. By blending in the grains left over from making beer, the bricks can be more environmentally friendly and better insulators.

Bricks are often impregnated with polystyrene as a way to enhance their heat-trapping abilities. This is appealing, because the bricks remain strong, and they can be built into energy-efficient buildings, says Eduardo Ferraz of the Polytechnic Institute of Tomar in Portugal. However, EU restrictions on carbon emissions have made it expensive to incorporate polystyrene and other synthetic materials into bricks.

Ferraz and his colleagues have now shown that brewery grains can be mixed into clay bricks to enhance their ability to trap heat, without compromising strength.

Spent grain for the process should be easily available, because commercial breweries produce huge quantities of it as a pulpy mixture that is usually used in animal feed or ends up in landfill.

With a clay paste containing 5 per cent spent grains, the team was able to create bricks just as strong as the conventional type, while reducing the amount of heat they lost by 28 per cent (Journal of Materials in Civil Engineering, The reason for this, the team says, is that the grains make the bricks more porous, and so they trap more air, which increases heat retention.

One thing could stand in the way of using this process, though: the smell. Bill Daidone of the Acme Brick Company, one of the largest brick manufacturers in the US, says his lab abandoned experiments because the stench of the moist grains was overpowering. “We opened up the bucket and it was terrible,” he says. This problem vanishes once the bricks are fired, though, says Ferraz.

Bricks that provide insulation without sacrificing strength could be a big boost to the brick industry, says John Sanders, a researcher at the National Brick Research Center at Clemson University in South Carolina.

“With the current concern for energy codes, I think the industry is open to change,” Sanders says.

This article appeared in print under the headline “Brewing benefits? Alcohol, hangovers and better bricks”

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Nov 23 2013

Graphene – the new wonder material

Graphene “The New Wonder Material”


Scientific interest rolls in for a material that is more solid than steel and a better conductor than copper

  • Graphene 3D illustration
3D illustration showing a sheet of graphene. Photograph: nobeastsofierce/Alamy

The molecule is priceless but it is not a matter of cost – a few hundred dollars per kilo. The value lies in its potential. The molecule in question is called graphene and the EU is prepared to devote €1bn ($1.3bn) to it between 2013 and 2023 to find out if it can transform a range of sectorssuch as electronics, energy, health and construction. According toScopus, the bibliographic database, more than 8,000 papers have been written about graphene since 2005.

As its name indicates, graphene is extracted from graphite, the material used in pencils. Like graphite, graphene is entirely composed of carbon atoms and 1mm of graphite contains some 3 million layers of graphene. Whereas graphite is a three-dimensional crystalline arrangement, graphene is a two-dimensional crystal only an atom thick. The carbons are perfectly distributed in a hexagonal honeycomb formation only 0.3 nanometres thick, with just 0.1 nanometres between each atom.

This 100% pure carbon simplicity confers some remarkable properties on graphene, very close to the calculated theoretical ones, as observed by the authors of A Roadmap for Graphene published in Nature last year.

Graphene conducts electricity better than copper. It is 200 times stronger than steel but six times lighter. It is almost perfectly transparent since it only absorbs 2% of light. It impermeable to gases, even those as light as hydrogen or helium, and, if that were not enough, chemical components can be added to its surface to alter its properties.

“Graphene is a platform, like a chessboard, on to which one can place the pawns you want. The subtlety lies in finding the right positions. There is a real beauty in its simplicity,” explained Vincent Bouchiat, from the Institut Néel in Grenoble, part of the National Centre for Scientific Research (CNRS). “The future lies in pencil graphite!” said Annick Loiseau, from the National Office for Aerospace Studies and Research (ONERA), coining a slogan. She is the French representative to the executive office of Graphene Flagship, a research consortium funded by the EU for the next 10 years.

The project was officially launched last month. “We have already learnt a great deal but new results could emerge in certain situations – only we don’t yet know which ones,” said Mark Goerbig, another CNRS researcher, who works in the solid physics department at Paris-Sud Orsay University.

This miracle material has come a long way. In theory, such a two-dimensional structure was believed to be unstable and therefore better rolled up, as observed in the 1990s with carbon nanotubes.

In 2004 two Russian-born scientists, Andre Geim and Konstantin Novoselov, along with others, published the first electronic measurements proving they had isolated graphene. They had removed carbon flakes from graphite using bits of sticky tape – which ultimately led to them winning a Nobel prize for physics in 2010.

“The theory only really held true for two dimensions, but in actual fact the crystal grows in a three-dimensional space and the small surface fluctuations, like waves, stabilise the crystal,” said Goerbig. Experiments rapidly confirmed the marvellous behaviour of this new material, which can be explained by a kind of sea of electrons on the surface that nothing can stop and that do not interact with each other. It’s as though the electrons have no mass and move at a speed 300 times slower than light. The mathematical equation to describe them is closer to that for high-energy particles than for solid matter, hence this outstanding performance that suggests so many potential uses.

Being transparent as well as a good conductor, graphene could replace the electrodes in the indium used in touchscreens. Since it is light, graphene could be integrated into composite materials to eliminate the impact of lightning on aircraft fuselages. It is also waterproof and would be perfect to use in hydrogen reservoirs.

Since nothing can stop the electrons, graphene cannot be “switched off” so in theory it is of little use in transistors, which are the key components of modern electronic goods. However, research is being carried out into ways of creating an artificial band gap that would enable it to be switched off and therefore used for that purpose.

The European consortium has decided to focus on a number of applications. “Our goal is to support innovation in Europe but also to create a network of specialists in contact with companies for long-term R&D projects,” said Stephan Roche, in charge of one section of the project, and a researcher at the Catalan Institute of Nanoscience and Nanotechnologies in Barcelona.

graphene illustrationA piece of graphene aerogel – weighing only 0.16 milligrams per cubic centimeter – is placed on a flower. Photograph: Long Wei/EPAThe major steps in this process have already begun. Several start-up companies are already manufacturing graphene, mainly for laboratories, using a variety of techniques. The “historical” one with sticky tape has been replaced by chemical exfoliation. An alternative is to use a carbon and silicon substrate, which is heated to remove the silicon atoms, leaving a layer of graphene on the surface. Yet another method is to place carbon on the surface of copper which, after heating, catalyses the graphene formation reaction. A team from Rice University in the US has even used a cockroach leg as a source of carbon.

In Europe, Applied Graphene Materials (AGM) in the UK and Avanzare and Graphenea in Spain are the spearheads. “If we want graphene to become the equivalent of silicon in microelectronics today, it is important to control the material and its quality,” said Etienne Quesnel of the French Alternative Energies and Atomic Energy Commission, in charge of the energy aspect of Graphene Flagship, which also works with manufacturing specialists.

Industry giants are in the running too. IBM has produced several electronic component prototypes, while Samsung has produced a flat screen (70cm in the diagonal) with graphene electrodes. The tennis racket maker Head used tennis champions Novak Djokovic and Maria Sharapova to promote rackets made with graphene. BASF and Daimler-Benz have designed a concept electric car called Smart Forvision that incorporates graphene in a conductive e-textile. In 2012, BASF produced a report on the future of graphene, forecasting a market worth $1.5bn in 2015 and $7.5bn in 2025.

It goes without saying that China is also in the race, with 2,600 articles published in Europe. And with more than 2,200 patents it has surpassed Europe and the US.

Last summer one start-up, Bluestone Global Tech, announced a partnership with a mobile phone manufacturer for the first graphene-based touchscreens to be launched on the Chinese market in the coming months. Nevertheless, mass applications are not yet in the pipeline.

“People are being sold graphene that is really graphite only more expensive,” said Marc Monthioux, from the CEMES research centre in Toulouse at a conference on graphene-based composite materials held in Paris earlier this year. Strictly speaking, graphene is single-layered, but manufacturing processes may create stacks of several layers. When more than 10 layers are created, the properties change enormously and resemble graphite more than graphene. “To date graphene is not absolutely superior to carbon nanotubes,” said Monthioux. According to Loiseau, “In composites it is necessary for the carbon, graphene or nanotube molecules to ‘touch’ each other to be conductive. That is easier for elongated nanotubes than for flake-shaped graphene, which explains the difference.” It takes a long time to develop a composite material and nanotubes have the advantage of being the more mature material. Nanotube researchers were not happy to see graphene arrive and grab both attention and funding.

Nevertheless, accumulated nanotube experience is very useful to speed up work on graphene. “It took six years to produce the first transistors with nanotubes,” said Loiseau. “With graphene, we had the first electric measurements in a year.”

As far as its medical use is concerned, knowledge of one material serves for the other. A crucial aspect of the European project is devoted to how to protect the people working with graphene as well as end users, in addition to researching possible medial applications. “At present we have studies showing no effect while others indicate a potential risk,” said Alberto Bianco, CNRS head of research at the Institute of Molecular and Cellular Biology in Strasbourg, who co-heads the health and environmental aspects of the European project.

In fact, as with carbon nanotubes, the considerable diversity of types of graphene need to be taken into account. Size certainly matters, but so does the chemical state. The molecule may be oxidised to a greater or lesser extent, or contain different amounts of residual impurities as a result of how the graphene is synthesised, or how its layers are built up. There is no definitive answer. In an article published in April in Angewandte Chemie, scientific journal of the German Chemical Society, Bianco quoted several contradictory studies, some of which found toxic effects on micro-organisms where others did not. Nor has any light been shed on the way graphene could cause damage to cells. Does the graphene cut through the cell wall perpendicularly or does it coat the cell?

“One optimistic note is that chemistry may enable us to modulate the biological activity of this nanomaterial,” said Bianco. For instance, by binding different chemical groups one might make the graphene more or less soluble, or guide it towards a given therapeutic target. Additional work is therefore required. The consortium will study the effects on different types of cells (cancerous, neuronal, related to the immune system etc)as well as on amphibians.

Another advantage of graphene is that is opens up paths to other two-dimensional materials as small as atoms. Boron nitridemolybdenum sulphate and tungsten or even 100% silicon sillicene are some of the peculiar sounding names that could become more common. Some isolate, others conduct. Piling up these molecules layer-by-layer would create new materials with new properties. The game is on.

This article appeared in Guardian Weekly, which incorporates material from Le Monde


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Nov 16 2013

Is it right to waste helium on party balloons?

Is it right to waste helium on party balloons?

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Nov 11 2013

Microwave signals turned into power

Microwave signals turned into power

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Nov 08 2013

Physics probes ‘splashback’ problem

Physics probes ‘splashback’ problem

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Nov 07 2013

Scientists reveal the full power of the Chelyabinsk meteor explosion

Scientists reveal the full power of the Chelyabinsk meteor explosion

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Oct 26 2013

Chris Hadfield: ‘I’m blind, in space, holding a drill. Houston, I have a problem’

Chris Hadfield: ‘I’m blind, in space, holding a drill. Houston, I have a problem’

Chris Hadfield: ‘I’m blind, in space, holding a drill. Houston, I have a problem’
An extract from Chris Hadfield’s An Astronaut’s Guide To Life On Earth
Chris Hadfield
Fri 25 October 2013
I am calm the night before my first spacewalk in 2001, but I am also conscious I am about to do something I’ve been dreaming of most of my life. I feel ready – I’ve studied and trained for years. Still, I spend hours polishing the visor of my spacesuit so my breath won’t fog it up, unpacking and checking each piece of gear, pre-assembling as much of it as I can, then carefully attaching it to the wall with Velcro. My crewmate Scott Parazynski and I are installing Canadarm2, the robotic arm that will build the International Space Station, currently still in its infancy. We docked our space shuttle, Endeavour, to it a few days before, but haven’t yet been able to open the hatch because our EVA (extravehicular activity, or spacewalk) is going to take place from the shuttle airlock – essentially a depressurised bridge between the two spacecraft.
There are multiple steps to follow for an EVA; mess one up and you won’t make it out of the spaceship. It will be many busy hours until we can float out of the airlock and Nasa has choreographed them down to five-minute slices, even dictating when and what to eat for breakfast: PowerBars and rehydrated grapefruit juice. I shave, wash up (hair-washing involves scrubbing your scalp vigorously with no-rinse shampoo, then drying off carefully to be sure stray wet hairs don’t wind up floating all over the spacecraft and clogging up air filters or eyes and noses) and use the toilet. (You pick up a thing that looks like a DustBuster with a little yellow funnel attached, then hold it up close so you don’t get pee everywhere. I don’t want to have to use my diaper if I can help it.) Then I pull on the liquid cooling garment, which is like long underwear with a lot of personality; it’s full of clear plastic tubing that water flows through, and we can control the temperature. It feels stiff, like a cheap Halloween costume, but when the sun is shining on you in a spacewalk, the fabric of the spacesuit gets extremely hot and personal air-conditioning seems like a fine idea.
Four hours later, Scott and I are finally floating head to toe in our spacesuits, carefully and slowly depressurising the airlock and checking and rechecking the LED displays on our suits to make sure that they are functioning properly and can keep us alive in the vacuum of space. If there is a leak in the suit out there, our lungs will rupture, our eardrums burst, our saliva, sweat and tears boil, and we’ll get the bends. The only good news is that within 10 to 15 seconds we’ll lose consciousness. Lack of oxygen to the brain is what will finish us off.
When the airlock has finally depressurised, I grab the handle on the hatch and turn it – not easily, because nothing in a spacesuit is easy. The hatch is like a manhole, and it has to be removed and stowed in a bike rack-like contraption overhead. My exit will not be graceful. But my number one concern is to avoid floating off into space, so I’m tethered to Scott and I’m holding another tether to attach to the rail on the side of the shuttle. I lower the gold shield on my visor to protect my eyes from the sun and carefully, gingerly, wriggle my bulky suited self out of the airlock. I’m still inside the belly of the beast, in the payload bay, but my suit has become my own personal spaceship, keeping me alive.
Emerging from the bay, my existence narrows to a single point of focus: attaching my tether to the braided wire strung from one end of the vehicle to the other. I lock on to that and tell everyone I’m securely tethered. Now Scott can come and join me. Waiting for him, I check behind me, to be sure I haven’t accidentally activated my backup tank of oxygen, and that’s when I notice the universe. The scale is graphically shocking. The colours, too. The incongruity is stupefying: there I was, inside a small box, but now – how is this possible? What’s coming out of my mouth is a single word: “Wow.” Only elongated: “Wwwooooowww.” My mind is racing, trying to understand an experience that is so unique. It’s like being engrossed in cleaning a pane of glass, then you look over your shoulder and realise you’re hanging off the Empire State Building, Manhattan sprawled vividly beneath. Of course I’d peered through the shuttle windows at the world, but I understood now that I hadn’t seen it, not really. Holding on to the side of a spaceship that’s moving around the Earth at 17,500 miles an hour, I could truly see the astonishing beauty of our planet, the infinite textures and colours. On the other side of me, the black velvet bucket of space, brimming with stars. It’s vast and overwhelming, this visual immersion, and I could drink it in for ever, only here’s Scott, out of the airlock, floating over towards me. We get to work.
After five hours, the installation is going well, albeit slowly, when I become aware of droplets of water floating around inside my helmet. An EVA is incredibly taxing, physically, and over the years we’ve tried putting some sort of food inside the suit so we have something to eat. But it’s been messy and more hindrance than help, so typically we just have a water bag. You bite on the straw to open a valve, then suck out water – hypothetically, anyway. My water bag hasn’t worked since we started the EVA and now it is apparently leaking.
I’m trying to ignore these little globs of water floating in front of my face when suddenly my left eye starts stinging. It feels as if a large piece of grit has been smashed into it. Instinctively I reach up to rub it – and my hand smacks into my visor. “You’re in a spacesuit, moron!” I remind myself. I blink repeatedly and whip my head from side to side to try to dislodge whatever it is, but my eye won’t stay open for more than a blurry second.
We’ve trained for many eventualities during an EVA, but partial blindness is not one of them. I’m tightening the bolts on Canadarm2 using a big handheld drill. My feet are clicked into the foot restraints and my tether is firmly attached to the space station; I’m at no imminent risk. I decide to keep working and tell no one. I move on to the next bolt, but my left eye is now not only smarting but actually filling with tears.

Hadfield at work in orbit. Photograph: Nasa/Newsmakers/Getty Images
Tears need gravity. On Earth, a little duct above your eye generates tears that flush out any irritant, then overflow down your cheek. In weightlessness tears don’t flow downward. They just sit there and, as you keep on crying, a bigger and bigger ball of salty liquid accumulates to form a wobbly bubble on your eyeball. The growing ball of tears in my left eye oozes over, like a burst dam, invading my right. Within just a few minutes, I’ve gone from 20/20 vision to blind. In space. Holding a drill.
“Houston, EV1. I have a problem.” As the words come out, I can picture the reaction on the ground. First there will be concern for me personally and then, seconds later, everyone at Mission Control will be galvanised, tossing out theories about causes and trying to figure out solutions.
To Scott and me, under-reacting seems the best option: I can’t see, but he’s fine and still working on the wiring on another part of the station. I need to get this job done; the Canadian-designed and built Canadarm2 is both a test and proof of our robotics capability. Crew safety is the number one priority, but we can’t just leave this vital piece of equipment flapping off the side of the space station. The EVA is also a big deal back home: no Canadian has ever walked in space before. In other words, it’s not a good time to be having eye trouble.
The focus on the ground is figuring out what’s causing the contamination. They go straight to the worst-case scenario: maybe the problem is related to the air purification system in the spacewalking suit, which relies on lithium hydroxide to remove carbon dioxide. Lithium hydroxide is caustic and can severely damage your lungs; eye irritation is one of the first signs of a leak. So maybe I’m experiencing early symptoms of exposure and have only a couple more minutes to live. Ellen Ochoa, the Nasa “capcom” who’s the voice of Mission Control, calmly tells me to open my purge valve – essentially, open a hole in my suit.
This goes against my survival instincts, but I start dumping my air into space. I listen to the hissing noise as my oxygen merrily burbles out into the universe. It’s a curiously peaceful moment. Without sight, my body is telling me that nothing out of the ordinary is going on. I feel more like I’m under the covers in bed than hanging on to the side of the station, in mortal danger.
The suit has a significant amount of oxygen, enough for eight or even 10 hours, and I also have a secondary O2 tank, so I can bleed oxygen and stay alive for a long time. But who knows how much longer we’ll have to be outside to finish attaching the arm? I start trying everything I can think of to unblind myself: shaking my head around to brush my eyes against something in the helmet, blinking for all I’m worth. I know the doctors on the ground are undoubtedly saying, “We’ve got to bring him inside right this minute and figure out what’s going on.” So I say, “I feel no lung irritation at all and I think my eyes are starting to clear a little bit.” It’s sort of true. I feel marginally less sightless. I keep blinking and thankfully, 20 minutes on, I think I can see well enough to continue.
Nearing the end (almost three hours later), I look down to watch the world pour by. Having overcome this obstacle and knowing the two of us have accomplished what we set out to do is a big moment. But with a spacewalk, the very last step is as important as the first one, so not until we’ve repressurised the airlock and are actually back inside our spaceship do I let myself relax. As soon as I do, I feel completely drained and just float limply, shivering with cold. My body is out of fuel.
Later, as we’re going over the possibilities of what went wrong, the capcom asks, “Chris, did you remember to use your anti-fog stuff?” Of course I had. The night before I’d polished the visor of the suit. “You didn’t get it all off.” Apparently the solution is basically dishwashing detergent; mix it with a few droplets of loose water and it’s as though you’ve squirted soap directly into your eye. A spacewalk with a multimillion-dollar piece of equipment absolutely vital to the construction of the ISS was jeopardised because of a microscopic drop of cleaning solution.
Eventually, Nasa changed the solution to something less noxious. But in the meantime, thanks to my widely publicised oversight, all astronauts knew to be fanatical about wiping down the interior of their visors. Even in my line of work, it’s the small stuff.
I missed my children in space, but no more than I do on the ground, where I don’t see enough of them either. And I missed my wife. But I wasn’t lonely. Loneliness, I think, has very little to do with location. It’s a state of mind. In the centre of every city are some of the loneliest people in the world. If anything, because our whole planet was just outside the window, I felt even more aware of and connected to the seven billion other people who call it home.

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Oct 16 2013

Meteorite pulled from Russian lake

Meteorite pulled from Russian lake

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