Posts Tagged‘pressure’

The Spacesuit of the Future.

The spacesuit of today is much the same as the one of the last few decades. It’s an incredibly complicated device, combining all the systems necessary to keep an astronaut alive in the vacuum of space into a wearable package. However it’s not the easiest thing to use, often requiring extensive training not only to get familiar with it but also to train your muscles in how to use it. This is mostly because the design, which makes even the slimmest astronaut look something like the Michelin Man, is centred on ensuring that the pressure on the astronaut’s body is kept constant. This is currently done using an inflated lining which is quite restrictive however future designs, like the one from MIT, could provide the same protection whilst giving astronauts far more freedom.

MIT BiosuitOur bodies are accustomed to 1 atmosphere of pressure which, on the grand scheme of things, really isn’t that much. Indeed the difference between what we’d consider normal pressure and a complete vacuum is about the same as going 10m under water, something SCUBA divers do on a regular basis. However the trick is ensuring that that pressure stays consistent and constant over your entire body which is what led to the spacesuits today. Interestingly though it doesn’t matter how that pressure is generated so the traditional method can easily be replaced with something that’s mechanical in nature, which is what the new BioSuit from MIT seeks to do.

Instead of covering the astronaut’s body in what amounts to dozens of inflated pillows the BioSuit instead looks to use Shape Memory Alloys (think nitinol wire, if you’ve ever played with it) to provide the pressure. Essentially they’d have a full body tourniquet that would be embedded with this wire and, upon heating, it would contract around the astronaut’s body, providing the required pressure. How that pressure would be maintained is still a problem they’re working out (as keeping the astronaut heating constantly isn’t exactly ideal) but seem to be making good progress with various clip designs that would keep the suit tight over the duration of a spacewalk. They’d still have to have the traditional fish bowl on the head however as employing a system like this on the head wouldn’t really be feasible.

Whilst a suit like this wouldn’t provide complete freedom of movement (think a wetsuit that feels like it’s a size too small) it would be a vast improvement over the current design. Right now every time an astronaut wants to move a part of their body they essentially have to compress the protective bubble of gas in their suit, something which ends up being extremely tiring over the course of a long duration spacewalk. A design like this would likely require far less energy to manipulate whilst also allowing them to move a lot more freely, significantly reducing the time they’d need to spend outside.

For me though it’s just yet another piece of sci-fi making its way into reality as we’ve long dreamed of spacesuits that would be like a second skin to its wearers. Better still it’s being made with technology that we have available to us today and so no exotic material sciences is required to bring it to fruition. We likely won’t see any astronauts wearing them any time soon (the cycles for these things are on the order of decades) but as time goes on I think it’ll be inevitable that we’ll move to suits like this, just because of the vast number of advantages they offer.

 

Seeing The Triple Point of a Substance.

At a high level I understand the concept of the triple point of a substance, the combination of temperature and pressure that can result in a substance existing in all 3 states, but practically I always had trouble understanding it. I think this was because I’d take it to it’s logical conclusion, I.E. that essentially the substance would exist in all 3 states simultaneously something which seems impossible. Of course in practical terms this never occurs with whatever substance existing in one of those 3 states, with the added ability to quickly change to another one. Explaining the concept is one thing though, seeing it in motion makes everything far more clear:

The liquid in the video is called cyclohexane which has four distinct solid phases. I don’t think we’re seeing a transition between any of those specifically though, the temperatures required to meet them are below freezing and that appears to be room temperature, but this video does show how the triple point functions. Slight variations in pressure and temperature cause the substance to rapidly change from solid to a liquid and even straight to boiling (which you assume is producing gas). You probably wouldn’t want to reproduce this experiment as a demonstration to kids, cyclohexane is a derivative of benzene and likely carries the same nasty health effects, but you can do similar things as long as you have a vacuum pump.

Fun With Hydrophobic Sand.

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.

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 😀