Posts Tagged‘experiment’

Struggling Against Static Electricity.

Everyone knows the standard static electricity experiment. You grab yourself a perspex rod and a wool cloth and, after some vigorous rubbing (often with a few innuendos thrown in), suddenly your perspex has the ability to attract pieces of paper. Most people will also understand the mechanism of action, the transference of charge that leaves the rod negatively charged and the cloth positively charged. What most people won’t know however is that friction isn’t required to generate a static charge. This is what can lead to hilarious situations like the one in the video below:

So if friction isn’t a requirement for generating a static charge how do these address labels get it? The answer is actually pretty interesting and has to do with the way adhesives work. For these address labels the adhesion comes from a chemical reaction, meaning that the address labels had a form of bond with the backing before they were torn apart. When this bond is broken both materials will gain or lose electrons, depending on where the material sits on the triboelectric series. I’d hazard a guess that the material that the address labels is made up of tends more towards the negative end of the spectrum, meaning that bin holds a strong negative charge.

This is what is responsible for the labels floating around in a seemingly random fashion before ejecting themselves out onto the floor. The effect wouldn’t have been immediate, each label would only carry a small negative charge, however past a certain point the negative field would have become big enough to repulse the small weight of each of the labels. If they were so inclined they could throw a positively charged piece of plastic in there and they’d all be attracted which would also be pretty interesting.

Or, if you wanted some real fun, if they rubbed their head with a balloon and then dunked themselves in there all the labels would gleefully stick to them. Not that that proves much, just that it’d be hilarious to see someone with shipping label backing stuck to them.

Euler’s Disk: Surprising Complexity.

As long time readers will know I’m a fan of simple experiments or demonstrations that have some underpinning scientific phenomenon. It was things like these that first spurred my interest in science, especially since places like Questacon (a must visit place if you ever find yourself in Canberra) were filled to the brim with experiments like them. Thus whenever I find one I feel compelled to share it, not so much for myself but in the hopes that when someone sees it their curiosity will be piqued and they’ll pass that same passion onto others. In that vein I give you Euler’s Disk, one of the most fascinating science based toys I’ve come across:

The disk gets its name from Leonhard Euler, an eighteenth century physicist and mathematician who was behind such revelations as infinitesimal calculus and many other fundamental things. He studied the disk as part of his other research however it wasn’t until recently that they found themselves back in the limelight again. Back in 2000 Cambridge researcher Keith Moffatt demonstrated that air resistance played only a small part in the rate in which the disk slowed down with the vast majority coming from the rolling resistance between the surface and the disk’s edge.

What interest me about it most is the gradual speed up of the revolutions coupled with the increasingly bizarre noise that accompanies it. Then, right at the end when it appears to be spinning at its fastest the disk stops, as if some outside force robbed it of all its momentum instantly. This demonstrates how momentum is conserved as the rate of precession of the disk increases as it spins downward. Explaining the phenomenon though is much harder than just watching it however, which is why it’s such a great scientific toy.

Super Cereal.

Looking at the ingredients labels on food can be both an insightful and frightening affair. I’ve long been in a habit of doing it and I always find it fun to research some of the more esoteric ingredients, well that is right up until I find out where some of them come from. It’s the old adage of not finding out how the sausage is made, although in reality you should probably consider that with all things that you put in your body. Still when I watched the following video I was honestly surprised to see the outcome, as I didn’t think the effect of extracting iron from cereal would be so dramatic:

The first half of the video explores the idea that there’s elemental iron within cereal which can then be attracted by a magnet. Whilst this is true to some degree, the iron within the cereal will feel an attraction to a magnet, you can actually perform the exact same experiment with cereal that is bereft of any elemental iron content. This is because water is a diamagnetic material which is a fancy way of saying that in response to a magnetic field it will create its own inverse field in response. For the cereal and magnet experiment this means the water actually divots around the magnetic field which the piece of cereal then falls into. The iron in the cereal helps this process along of course, but it’s not the only force at play here.

However the extraction of the iron from the cereal was pretty astonishing, especially considering just how simple it was to do. Trying to extract other elements from the cereal would prove a much harder endeavour which is why I think an experiment like this is such a powerful visual aid. You’re literally seeing the iron being pulled from the food you eat which, in turn, makes you think about all the other things that are listed on the ingredients label. It might not be a particularly pretty picture that you end up with, but at least you’ll be far more aware.

I wish I knew about these kinds of science experiments when I was a kid!

Death Valley’s Sailing Stones Mystery Revealed.

The Sailing Stones of Death Valley have been a scientific curiosity for numerous decades. These rocks seemingly spring to life at various times throughout the year, blazing long trials across the desert’s floor before coming back down to rest. Whilst there have been numerous theories as to what causes this movement, ranging from the plausible to the downright insane, no one had managed to verify just what exactly was going on with these strange rocks. Well now thanks to researchers at the Scripps Institute of Oceanography we now have evidence of just what’s causing this to happen and it’s pretty fascinating.

The video largely supports the theory put forth by Ralph Lorenz some years ago whereby the the rocks are trapped within ice sheets which are then moved by the prevailing winds. What’s interesting about this video is that it shows why the previous experiments, which were largely inconclusive as to ice sheets being responsible, produced the data that they did. It also shows why there seems to be similarities between some movements whilst others seem to be completely random. Pretty much all of these can now be explained by the ice sheets breaking up and bumping off each other, leading to the wide variety of patterns and behaviours.

Like the video says this might not be the most exciting experiment to conduct however it’s always interesting when a long standing phenomena like this finally gets explained. We might not be able to use this knowledge to further other research or develop some novel product, however as we begin to explore further out into our universe knowledge of strange things like this becomes incredibly valuable. When we see phenomena like this elsewhere we’ll be able to deduce that similar processes are in action over there and thus further our understanding of the places we explore.

Facebook is Being Creepy Again, But They Didn’t Have to be.

In the now decade long history of Facebook we’ve had numerous scandals around the ideas of privacy and what Facebook should and should not be doing with the data they have on us. For the most part I’ve tended to side with Facebook as whilst I share everyone’s concerns use of the platform is voluntary in nature and should you highly object to what they’re doing you’re free to not use them. The fact is that any service provided to you free of charge needs to make revenue somewhere and for Facebook that comes from your data. However this doesn’t seem to stop people from being outraged at something Facebook does with almost clockwork regularity, the most recent of which was tinkering with people’s feeds to see if emotions could spread like the plague.

Facebook HeadquartersThe results are interesting as they show that emotions can spread through social networks without the need for direct interaction, it can happen by just reading status updates. The experimenters sought to verify this by manipulating the news feeds of some 689,000 Facebook users to skew the emotional content in one direction and then saw how the user’s emotional state fared further down the line. The results confirmed their initial hypothesis showing that emotions expressed on Facebook can spread to others. Whilst it’s not going to cause a pandemic of ecstasy or sudden whirlwind of depression cases worldwide the evidence is there to suggest that your friend’s sentiment on Facebook does influence your own emotional state.

Whilst it’s always nice to get data that you can draw causal links from (like with this experiment) I do wonder why they bothered to do this when they could’ve done much more in depth analysis on a much larger subset of the data. They could have just as easily taken a much larger data set, classified it in the same way and then done the required analysis. This somewhat sneaks around the rather contentious issue of informed consent when it comes to experiments like this as there’s no indication that Facebook approached these individuals before including them in the experiment.

Indeed that’s probably the only issue I have with Facebook doing this as whilst the data they have is theirs to do with as they see fit (within the guidelines of privacy regulations) attempting to alter people’s emotional state is a little too far. The people behind the study have came out and said that the real impact wasn’t that great and it was all done in aid of making their product better something which I’m sure is of little comfort to those who object to the experiment in the first place. Whilst the argument can be made that Facebook already manipulates users feeds (since you don’t see everything that your friends post anymore) doing so for site usability/user engagement is one thing, performing experiments on them without consent is another.

If Facebook wants to continue these kinds of experiments then they should really start taking steps to make sure that its user base is aware of what might be happening to them. Whilst I’m sure people would still take issue to Facebook doing widespread analysis on user’s emotional state it would be a far cry from what they did with this experiment, one that would likely not run afoul of established experimental standards. The researchers have said they’ll take the reaction to these results under advisement which hopefully means that they might be more respectful of their user’s data in the future. However since we’re going on 10 years of Facebook doing things like this I wouldn’t hold my breath for immediate change.

 

The Universe’s Strange Preference for Matter.

In the beginning, the one where time itself began, the theory goes that matter and antimatter were created in equal amounts. When matter and antimatter meet they annihilate each other in a perfect transformation of matter into energy which should have meant that our universe consisted of nothing else. However, for some strange reason, the universe has a small preference for matter over antimatter, to the tune of 1 parts in 10 billion. This is why our universe is the way it is, filled with billions of galaxies and planets, with the only remnant of the cataclysmic creation being the cosmic microwave background that permeates our universe with bizarre consistency. The question of why our universe has a slight preference for matter has puzzled scientists for the better part of a century although we’re honing in on an answer.

ALPHA Antimatter TrapIf you had the ability to see microwaves then the night sky would have a faint glow about it, one that was the same no matter which direction you looked in. This uniform background radiation is a relic of the early universe where matter and antimatter were continuously annihilating each other, leaving behind innumerable photons that now permeate every corner of the known universe. What’s rather perplexing is that we haven’t observed any primordial antimatter left over from the big bang, only the matter that makes up the observable universe. This lack of antimatter means that, for some reason or another, our universe has an asymmetry in it that has a preference for matter. Where this asymmetry lies though is still unknown but we’re slowly eliminating its hiding spots.

The Antihydrogen Laser Physics Apparatus (ALPHA) team at CERN has been conducting experiments with antimatter for some time now. They have been successfully capturing antiprotons for several years and have recently moved up to capturing antihydrogen atoms. Their approach to doing this is quite novel as traditional means of capturing antimatter usually revolve around strong magnetic fields which limit what kinds of analysis you can do on them. ALPHA’s detector can transfer the antihydrogen away from their initial capture region to another one which has a uniform electric field, allowing them to perform measurements on them. Antihydrogen is electrically neutral, much like its twin hydrogen, so the field shouldn’t deflect them. The results have shown that antihydrogen particles have a charge that’s equivalent to 0, showing that it shares the same properties as its regular matter brethren.

This might not sound like a much of a revelation however it was a potential spot for the universe’s asymmetry to pop up in. Had the charge of the antihydrogen atom been significantly different from that of hydrogen it would’ve been a clue as to the source of the universe’s preference for matter. We’ve found that not to be the case so it means that the asymmetry exists somewhere else. While this doesn’t exactly tell us where it might be it does rule out one possibility which is about as good as it gets in modern science. There’s still many more experiments to be done by the ALPHA team and I have no doubt they’ll be significant contributors to modelling just similar matter and antimatter are.

 

The State of Warp Drive Science.

The biggest challenge we face when exploring space is the almost incomprehensible amount of travel we have to do just to get to other heavenly bodies to explore. The fastest craft we’ve ever launched, the New Horizons probe, will take approximately 9 years to reach Pluto and would still take tens of thousands of years to reach another star once it’s completed that initial mission. There are many ways of tackling this problem but even if we travel as fast as the fastest thing known (light) there are still parts of our galaxy that would take thousands of years to reach. Thus if we want to expand our reach beyond that of our cosmic backyard we must find solutions that allow us to travel faster than the speed of light. One such solution that every sci-fi fan will be familiar with is the warp drive.

Now many will be familiar with the concept, a kind of space engine that allows a craft to travel faster than the speed of light, however fewer will know that it actually has roots in sound science. Essentially whilst nothing can travel faster than light space itself can expand at a rate faster than light travels, a property we have already observed. The trick, of course, is being able to manipulate space in such a way that it shrinks in front of you and expands behind you, something which required a kind of exotic matter that, as of yet, has not been created nor observed. However if you watch the video above (and I highly recommend you do if you can spare the hour) you’ll see that there’s been some amazing progress in validating the science behind the warp drive model and it’s quite incredible.

For me the most amazing thing about the presentation was the use of a toroidal capacitor as a space warping device. The idea of a warp drive has long hinged on the idea that a new type of matter would be required in order to create the expanding and contracting regions of space. However White’s experiments are instead seeking to validate if a positive energy density field could create the required negative pressure zone, negating the need to actually create exotic matter. As he states in the video however the results are non-negative but not conclusive so we don’t know if they’re creating a warp field yet but further experimentation should show us one way or another. Of course I’m hoping for research in the positive direction as the other improvements White and his team made to the original Alcubierre designs (reducing the energy required to sustain the field) mean that this could have many practical applications.

The video also goes on to talk about Q-Thrusters or Quantum Vacuum Plasma Thrusters which I’ve written about here previously. What I didn’t know was just how well those thrusters scaled up with bigger power sources and if their models are anything to go by they could make many missions within our solar system very feasible, even for human exploration. Keen observers will note that a 2MW power supply that comes in at 20 tons is likely to be some kind of fissile reactor, something which we’re going to have to adopt if we want to use this technology effectively. Indeed this is something I’ve advocated for in the past (in my armchair mission to Europa) but it’s something that’s going to have to be overcome politically first before the technology will see any further progress.

Still this is all incredibly exciting stuff and I can’t wait to hear further on how these technologies develop.

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.

Saturn’s Hexagon and a Table Covered in Clay.

One of the strangest phenomena I’ve ever read about in our solar system (and there are many, like Venus spinning in the opposite direction to everyone else, but that’s a story for another day) none are more perplexing than the hexagon atop of Saturn. It’s strange because shapes like that don’t typically appear in nature, especially at scales of that magnitude. The question of how it came to be, and more importantly why it keeps sticking around, was an interesting one and whilst there’s a sound scientific explanation for it a video shared to me by a friend showcases how the effect can come about.

You can see the effect most strongly at around 2:30 where he starts moving from the center of the spinning disk back towards the outer edge and, lo and behold, suddenly we have a hexagon shape created by a simple motion on a rotating disk. It’s easy to make the comparison between the spinning disk and the incredible winds that sweep across Saturn’s surface, but what about the artist’s arm motion? We can see it’s a simple periodic, much like a pendulum, but the scale of which these two forces act on would almost preclude any kind of relationship. As it turns out there are in fact some similarities but the mechanisms of action are far more complex.

The current theory is that the hexagon isn’t created by the wind currents per se, as the original spinning a bucket of water experiment would lead you to believe, instead its created by the differing wind speeds that are present throughout Saturn’s atmosphere. These differing wind speeds buffet against each other creating vortexes, eddies and waves. As it turns out Saturn’s north pole has the steepest wind gradient which gives rise to the hexagon. With this in mind the researchers created a system whereby they could spin a cylinder and its base at different speeds creating a gradient similar to that on Saturn and, with a little tweaking, a hexagon appeared.

Now you know all that you should take a look at the latest movie of Saturn’s north pole from Cassini showing the speed gradient in effect. Absolutely incredible, don’t you think?

The Barking Dog Experiment.

I was watching one of the latest Mythbusters episodes recently when I noticed a strange phenomenon that looked oddly familiar. The experiment in question was testing the myth that a gun won’t fire in space (I.E. a perfect vacuum) something which Hollywood has a troubled past with. Whilst the answer was somewhat obvious before they began (hint: the answer, and the reasons behind it, are the same if you fired it underwater) the result was very impressive. Unfortunately I can’t find a direct link to the video however their high speed footage was nearly identical to what the Barking Dog experiment looks like, as shown in this video:

Seeing everything in slow motion is extremely interesting because it clearly shows how the sound is produced along with the characteristic light show. The flame front bouncing off the fuel saturated area pushes out the air above it, creating the sound, and as it approaches the bottom the time between those pulses rapidly decreases changing the tone of the resultant sound. In the Mythbusters episode you could see a lot of similarities although because it wasn’t an open ended system (due to the use of a vacuum) the sound produced was more of a descending low tone as the gas created by the bullet diffused and the shock wave ricocheted around.