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Posts Tagged ‘water’

Ice Crystal Formation on a Soap Bubble.

March 6th, 2013 No comments

Thanks to our northern hemisphere counter-parts I’ve been privy to all sorts of interesting cold weather things from making instant snow to the ingenuity that people come up with when they’re snowed in. Here in Australia we do get the up on the other end of the spectrum quite often during summer however although that doesn’t really drive us to do much more than sit around a pool and drink copious amounts of beer. So you can imagine then that anything involving sub-zero temperatures is going to be somewhat intriguing to us, especially something as cool as this:

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There’s nothing particularly complicated about what’s going on here but the demonstration is quite novel. What you’re seeing is the formation of ice crystals on the surface of a soap bubble which starts off slow but ramps up significantly as more crystals form. I think this is partially due to the way crystals form as they usually need a rough surface to attach to. This is how those instant ice videos work as the bottles don’t have any anchor points for the crystals to form but once you shake it up a bit you give them a surface to attach to.

There was one question that was left unanswered due to the video cutting off at the end however: whether or not it’d still float after it was frozen.

Now the bubble isn’t increasing in mass, it’s simply changing forms. There’s the possibility that some of the moisture from the air outside the bubble will condense onto the crystalline surface however I don’t think that’d change the mass by an appreciable amount. The density would also be going down as well thanks to water’s intriguing property of getting less dense as changes into ice. All those factors together would indicate that a frozen soap bubble would behave in much the same way as a regular one but I’d still like to see this hypothesis tested.

Although I do much prefer warmer climates, so this will have to be an exercise that’s left up to the reader.

Red Hot Metal And Water – The Reaction Isn’t What You’d Expect.

January 11th, 2013 No comments

There’s a really interesting experiment you can do in the comfort of your own home that demonstrates an effect I’m about to show you. All you need is a frying pan and some water. Heat up the frying pan until its good and hot and then flick droplets of water onto the pan. Curiously the droplets won’t instantly burst into little puffs of steam, instead they’ll skitter around on the surface of the pan in apparent defiance of the blazing surface that’s underneath it. This effect happens when any kind of liquid comes into contact with a surface past a certain temperature but I hadn’t really considered what would happen if you put the surface in the liquid:

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The phenomenon at work here is called the Leidenfrost Effect. It’s a pretty cool reaction whereby an initial layer of vapour formed by a liquid hitting a sufficiently hot surface forms a protective barrier which is what allows those water droplets I described earlier to skitter around rather than turning into steam. It’s clearly visible in the video at the start where a pocket of water vapour forms around the outside of the red hot sphere. It eventually collapses as the vapour isn’t a perfect insulator but it does manage to stay quite hot for a lot longer than you’d expect.

One thing I can’t figure out a good explanation for those is the incredible sounds that are produced. The rapid generation of steam could possibly explain part of it as some of the sounds are similar to what you hear from say a steam wand on a coffee machine but most of them have a definite metallic twang to them. It’s quite possible that all of the noises are coming from the ball itself as it cools down much like some cars which make a distinct “tink” noise when turned off (the noise comes from the exhaust pipe cooling down). I wasn’t able to track down a name or reliable explanation for this effect however so if you’ve got one I’m all ears ;)

Fun With Hydrophobic Sand.

November 15th, 2012 No comments

There’s been something of an explosion of hydrophobic (something that’s literally water proof) products recently. Many of the products are pretty novel ideas that have practical applications like shoes and boots but there are many other, stranger devices like this device that can pick up condiments spilled on a table. I thought I had seen most of the cool applications of hydrophobic coatings already until I came across this little gem the other day and the science behind what you see in it is quite awesome.

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So this sand, called Magic Sand which you can buy or even make yourself, starts to act in a rather odd way once it gets under water. You’ll notice that it sometimes takes a bit of effort to actually get it under the water and that’s because, just like oil, it would prefer to float on top of it rather than mix with it. Once its under there however it seems to stop acting like a power and starts acting like a semi-solid, being quite malleable. Once you take it out of the water however it returns to its former powder state, losing any of the properties it just had.

The reason for this is pretty simple and would have some pretty cool effects if they had a deeper tank or a pressurized container. Once the power is under water its put under pressure by all the water molecules around it, much like SCUBA divers are. This forces it to clump together which is what gives the sand its apparently malleability. Once its removed from the water this pressure is gone and we’re left with the powder we had before hand. If you had a really deep tank and did the same experiment the sand would become less and less malleable as the depth increased as the pressure exerted on it would continue to go up. Dropping some of this into the Mariana Trench would likely give you a hydrophobic rock by the time it reached the bottom, and an incredibly dense one at that.

The sand also has a practical purpose other than being a cool science based toy. Originally it was developed as a solution for surface oil spills where you’d cover the spill with the dust which would then be heavy enough to sink allowing for recovery. That method is unfortunately too expensive to be used and most clean ups instead rely on booms and specially designed ships but it is being tested for other applications.

Man if my younger self could see me now. He’d be wondering why the hell a grown man was so interested in all these boring, educational things. I seriously can’t get enough of them now :D

Europa, We Should Attempt Landings There.

November 17th, 2011 No comments

Carl Sagan is quote as saying that “life looks for life”. Indeed if our own history is anything to go by we’re in a constant state of searching out other forms of life and just recently we’ve extended that search beyond the confines of the world that gave rise to us. So far our search beyond our home world has proved fruitless as we’ve been unable to find any direct indications of life on any other heavenly body that’s within our reach. Thus we find Earth in what appears to be some great isolation which is a somewhat disconcerting notion given the age of the universe and the number of potential habitable planets in our galactic backyard. We should not be discouraged however as our quest to find life elsewhere is only just beginning.

Of all the other heavenly bodies that inhabit our solar system there’s one that stands out as the best candidate for housing life. Now if I was to ask the question of which body it was most people would respond with Mars as it’s the only planet that resembles Earth in some fashion, with the next closest candidate being the raging hell of Venus. It’s not a bad guess either as we’ve proven several times over that there was once vast amounts of water there and there’s still a very good chance there’s liquid water present today. However Mars is a very inhospitable place so much so that the best hope for life there is nothing above microbial and even that seems like a far reaching prospect.

Europa on the other hand is quite the curiosity. As far as moons go it really is something out of left field being a striking combination of bright whites and browns. It’s surface is also one of the smoothest in the solar system thanks to it being made almost entirely of water ice. That doesn’t mean it’s featureless however as the entire surface is criss-crossed with fracture lines from the giant ice sheet breaking apart and reforming. Many have speculated that this is because the surface actually lies on top of a giant subsurface ocean and when cracks form the ocean rushes up to fill it, forming the characteristic lines. It’s this undersea ocean that makes Europa one of the best candidates for life forming outside of Earth and recent studies show it just got a little better.

The potential ocean on Europa would be some 3KM below the surface, quite a ways away from any direct sunlight or other potential energy sources. It’s theorized then that the ocean is kept liquid by the tidal flexing that Europa undergoes every time it orbits Jupiter which could also drive the same kinds of volcanism processes that gives rise to life in the depths of our oceans. However recent research shows that there’s potential for some subsurface lakes that are much closer to the surface than the great ocean below. These lakes would have a higher rate of churn between water and ice providing a much a habitat that’d be more nutrient rich and hopefully more hospitable to life. Of both these recently modelled oceans and the great subsurface ocean haven’t yet been conclusively proven, but that just makes Europa a really tantalizing target for exploration.

Quite a few missions have swung past Europa already with the most detailed analysis being done by the Galileo craft from 1995 to 2003. However we haven’t been back there recently save for a short flyby by the New Horizons craft that imaged it on its way to Pluto. If we were to go back there my favourite mission candidate would be the Crybot style mission. In essence it’s a probe that’s fitted with a giant heater on the front of it, capable of plunging through several kilometres of ice. Once it broke through it would then deploy a small autonomous underwater vehicle that could investigate the subsurface ocean. This mission hasn’t got past the back of the napkin style planning stages yet, but I’m hopeful that we’ll one day attempt such a mission.

Europa is a curiosity unlike any other in our solar system and there’s so much we could learn from it if we were to send a mission there. Whilst the environment there isn’t really human friendly (the radiation at the surface is quite large, about 450 chest x-rays a day worth) it’s definitely within our current capabilities of robotic exploration. I know that one day we’ll see a dedicate mission there but until then I’m quite content to continue fantasizing about the undersea world that it contains and the tantalizing possibility that as of yet unknown life forms exist there.

Colonization and the Case for Mars.

June 17th, 2010 2 comments

As humanity stands right now we’re only dipping our toes into the vast and wondrous universe that we live in. Our current endeavors to survive outside of the world that gave us life have been limited to short frolics to our closest celestial neighbor as well as extended trips at high speeds through our upper atmosphere. However our attempts to establish ourselves beyond the comfort of our own home have, for the past 40 years, remained firmly in the realm of dreams. Today we bear witness to such magnificent events that are set to rekindle that adventurer spirit that has been long dormant in mankind, paving the way for us to once again brave the unknown.

Whilst my ambition to see humans turn into a true space faring race my stem from a selfish desire to have one of my most desired dreams realized I also truly believe that if humanity is to survive long into the future we must journey to other worlds. As it stands right now the human race is vulnerable to extinction events which, whilst extremely unlikely, would see the end of the human race as we know it. Establishing ourselves away from our home world would not only teach us how to live more sustainably, it would also ensure that even in the most tragic of circumstances we as humans would continue on.

So where would we go to satisfy such an ambition? There really is only one answer:

Realistically however, the answer is more complicated than that.

Officially there are 8 planets that make up our solar system with multiple other bodies that don’t quite fit our current classifications of heavenly bodies. Of these half of them are what we call giants having sizes and masses ranging from 15 to 317 times that of earth. Humans would have no chance of ever surviving on these beasts as the gravity and radiation that these planets emit are extremely deadly to us organic beings. Of the 4 remaining planets we’re already inhabiting one of them, another a scorching ball of rock, one a warning sign to how devastating green house gases can be and finally a lone ball of red dust. You’d be forgiving for thinking that all of them bar our current home wouldn’t be worth trying to settle on but as it turns out our red cousin might just have what it takes to make ourselves at home.

It’s been known for quite some time that there are reserves of water ice on Mars. In what quantities and purities isn’t so definite, but there are significant amounts tied up in permafrosts, minerals and in ice sheets under the Martian surface. Using current day technology we would be easily able to extract enough to support a permanent colony on our red sister, even without the help of earth for resupply. Granted the best locations for water are not the best locations for people (it’s rather cold at the poles) but the fact remains that one of life’s most essential ingredients is in plentiful supply. Couple that with Mars’ soil having the unusual characteristic of being good for growing asparagus and you have the potential for the beginnings of a real ecosystem, something that Mars has lacked for millions of years.

Many will tell you that before we can even think of establishing ourselves on Mars we have to first conquer the challenge of living on our closest neighbor, the Moon. It’s an interesting proposition as many of the technologies that need to be developed to colonize another planet like Mars would also be applicable. The Moon as it stands is far more inhospitable to life which means that if we could prove that we could colonize it then basically any other reasonable heavenly body is possible as well. Still if Mars and the Moon were both equal in distance and travel time I highly doubt there would be any discussion over where we would be going next, as Mars is infinitely more valuable to us than the Moon. Still the fact remains that the furthest any human has ever gone away from home is no where near the time required to get to our sister planet, and that is insurmountable task that we face.

Honestly I would be all for a Moon colony as it would make future deep space missions much more feasible and would open up all sorts of opportunities such as a 100m telescope that would be almost 2000 times more sensitive than the Hubble Space Telescope. However most current plans to return to our celestial twin are often little more than flag planting exercises with no intention of setting up a permanent base of operations there. That is why I don’t support many of the proposals as their vision falls short of what is required to truly push humanity beyond our current comfort zone. Japan is probably the most forward thinking in this regard with their plans to build a robot base there by 2020.

I am by no means saying that this would be an easy endeavor. Cost estimates for a return mission start at a modest $55 billion which for comparison is just under half of what the International Space Station has cost. Most likely setting up a permanent colony on Mars would require dozens of such missions easily tipping the cost towards the trillions. Still we know that attempting such things spurs on many economic benefits that are many times greater than their cost to society. This would be the least of all the benefits that colonizing Mars would bring to the human race.

If that doesn’t convince you, maybe this will:

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