Mpemba made his accidental discovery in Tanzania in 1963, when he was only 13 years old and in secondary school. In spite of widespread disdain from his classmates, he surreptitiously continued experiments on the phenomenon until he had the good fortune in high school to interact with Professor Denis Osborne of the University College Dar es Salaam. Osborne was intrigued, carried out his own experiments, and in 1969 the two published a paper in the journal Physics Education.

…

So what did Osborne’s research show? He placed a 100 cm³ beaker filled with 70 cm³ of water on a sheet of insulating foam in a freezer, and timed how long it took for the water to freeze. For temperatures up to 20 °C, the time was roughly proportional to the temperature above freezing, up to a maximum of 100 minutes at 20 °C. For higher temperatures, however, the time dropped dramatically, down to 40 minutes for 80 °C water!

Be sure to read the complete article for the whole story, including many attempts to characterize the Mpemba effect over the years. 50 years later there still isn’t a strong consensus about what causes the effect, and in many cases it’s supposed to be difficult to reproduce.

To me, this is crying out for a citizen-science experiment with lots of participants, similar to the way Biocurious works. The experiments themselves are dirt simple (and cheap) to implement; all they really require is water, a heater, and a freezer. The rest is a matter of documenting all the (potentially) relevant variables, including the heater and freezer used, the source of the water, the type of containers, and even the geocoordinates of the experimenter. (Hey, who knows, right?)

A second generation of citizen-science experiments could then be designed based on trends in the first-generation data. The fun thing about this step is that (as Galaxy Zoo has shown) the data often suggests results that weren’t expected before it was being collected. (That shouldn’t be surprising; this is science after all.)

The point of each subsequent generation would be to build more accurate predictions of which experimental setups would or would not produce the Mpemba effect. Eventually it should be possible to make a set of statements like, “Heating 50 ml of 20 °C tap water in a 100W microwave for 90 seconds is 90% likely to reduce the time required to freeze it in a 1 m³ freezer by 35%.”

Why the citizen-science approach? I suspect that rather than trying to control all the known factors to produce the desired result, we instead want to track as many factors as possible to characterize the space of results. This particular effect will probably require a “vast multidimensional array of experiments“* to characterize properly, so enlisting a large number of citizen scientists makes a lot of sense.

Besides, each and every one of the test participants can have fun guessing at the real causes involved. Who doesn’t love a little armchair theorizing?

* Yes, I’m ‘citing’ Wikipedia. The original article cited there is inaccessible, and the rest of the Wikipedia summary is informative stuff.

Electrons, in their secret life as wibbly-wobbly quantum particle-wavey things, have a property called spin. To quote a handy article I just ran across:

One of the things that was clear from experiments was that electron have spin. A first naive picture of an electron – this is not an accurate picture but it’s a start – is as a tiny ball with electric charge – which is what flows when a current flows in a wire. If you spin a ball of electric charge, the electric charge goes around in a circle. You effectively have a tiny current going around, and when you have a current like that you have a magnetic field – the electron becomes a tiny magnet. The presence of that magnetic effect is pictured as the electric charge spinning around. If the electron was still, it wouldn’t have this magnetic effect.

It gets better:

Among the many counterintuitive properties of the electron is the fact that it has spin one-half. This is the mathematical way of saying that if you rotate an electron through 360 degrees, it doesn’t look like it did before you started! There is no parallel for this in our everyday world – we are accustomed to being able to turn objects through 360 degrees and get them back to where they started.

Oh, but there is a parallel in the everyday world, or at least in my slightly-twisted mind. Think of it like so:

1. Imagine a reel-to-reel film projector. Running a short length of film through end-to-end works like you think it would.
2. Tape one end of the film to the other; now you have a continuous loop of film that repeats itself. This would correspond to a spin of 1, because it looks the same after one loop.
3. Now tape one end of the film to the other backwards, to make a Möbius strip. The film still loops, but now it does one loop with the frames reversed left-to-right. It doesn’t repeat itself exactly until the film has looped through twice, corresponding to a spin of 1/2.

Does this mean that electrons are actually tiny loops of film? No. It only provides an analogy for this one property, and even then it might not go very far. Still, as soon as someone says “there is no X”, I have to find a counterexample. :)

It always seemed to me that you should only need to assign one or the other. If you have a deadline, then what does the priority affect? If the item is high enough priority, isn’t the due date ASAP?

Today, though, I had a flash of insight. The due date defines how much I have to work on the item in order to get it done in time, almost like the velocity of the task. The priority, however, defines how resistant the job is to being derailed by other tasks, more like the inertia or mass of the task.

Put that way, the two values aren’t redundant at all. In fact, you can put them together to determine the overall momentum of a project, based on the combination of the deadline-driven velocity and the priority-based mass. It might even be possible to come up with a formula for determining the outcome of a collision between two tasks, but I’ll leave that as an exercise for the project manager.

I mean, seriously, just because they lack endoskeletons and have more appendages than you do is no reason to get all squeamish.

Here, we’ll start you off slowly with some really, really important bugs: native honeybees and bumble bees (one of my favorites). And they’ve got all these cool books and guidelines.

This is really fascinating stuff, folks.

Read this.

Then watch this:

And to quote from Jonathan Haidt’s article:

Here’s my alternative definition: morality is any system of interlocking values, practices, institutions, and psychological mechanisms that work together to suppress or regulate selfishness and make social life possible. It turns out that human societies have found several radically different approaches to suppressing selfishness, two of which are most relevant for understanding what Democrats don’t understand about morality.

First, imagine society as a social contract invented for our mutual benefit. All individuals are equal, and all should be left as free as possible to move, develop talents, and form relationships as they please. The patron saint of a contractual society is John Stuart Mill, who wrote (in On Liberty) that “the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others.” Mill’s vision appeals to many liberals and libertarians; a Millian society at its best would be a peaceful, open, and creative place where diverse individuals respect each other’s rights and band together voluntarily (as in Obama’s calls for “unity”) to help those in need or to change the laws for the common good.

Psychologists have done extensive research on the moral mechanisms that are presupposed in a Millian society, and there are two that appear to be partly innate. First, people in all cultures are emotionally responsive to suffering and harm, particularly violent harm, and so nearly all cultures have norms or laws to protect individuals and to encourage care for the most vulnerable. Second, people in all cultures are emotionally responsive to issues of fairness and reciprocity, which often expand into notions of rights and justice. Philosophical efforts to justify liberal democracies and egalitarian social contracts invariably rely heavily on intuitions about fairness and reciprocity.

But now imagine society not as an agreement among individuals but as something that emerged organically over time as people found ways of living together, binding themselves to each other, suppressing each other’s selfishness, and punishing the deviants and free-riders who eternally threaten to undermine cooperative groups. The basic social unit is not the individual, it is the hierarchically structured family, which serves as a model for other institutions. Individuals in such societies are born into strong and constraining relationships that profoundly limit their autonomy. The patron saint of this more binding moral system is the sociologist Emile Durkheim, who warned of the dangers of anomie (normlessness), and wrote, in 1897, that “Man cannot become attached to higher aims and submit to a rule if he sees nothing above him to which he belongs. To free himself from all social pressure is to abandon himself and demoralize him.” A Durkheimian society at its best would be a stable network composed of many nested and overlapping groups that socialize, reshape, and care for individuals who, if left to their own devices, would pursue shallow, carnal, and selfish pleasures. A Durkheimian society would value self-control over self-expression, duty over rights, and loyalty to one’s groups over concerns for outgroups.

A Durkheimian ethos can’t be supported by the two moral foundations that hold up a Millian society (harm/care and fairness/reciprocity). My recent research shows that social conservatives do indeed rely upon those two foundations, but they also value virtues related to three additional psychological systems: ingroup/loyalty (involving mechanisms that evolved during the long human history of tribalism), authority/respect (involving ancient primate mechanisms for managing social rank, tempered by the obligation of superiors to protect and provide for subordinates), and purity/sanctity (a relatively new part of the moral mind, related to the evolution of disgust, that makes us see carnality as degrading and renunciation as noble). These three systems support moralities that bind people into intensely interdependent groups that work together to reach common goals. Such moralities make it easier for individuals to forget themselves and coalesce temporarily into hives, a process that is thrilling, as anyone who has ever “lost” him or herself in a choir, protest march, or religious ritual can attest.

In several large internet surveys, my collaborators Jesse Graham, Brian Nosek and I have found that people who call themselves strongly liberal endorse statements related to the harm/care and fairness/reciprocity foundations, and they largely reject statements related to ingroup/loyalty, authority/respect, and purity/sanctity. People who call themselves strongly conservative, in contrast, endorse statements related to all five foundations more or less equally. (You can test yourself at www.YourMorals.org.) We think of the moral mind as being like an audio equalizer, with five slider switches for different parts of the moral spectrum. Democrats generally use a much smaller part of the spectrum than do Republicans. The resulting music may sound beautiful to other Democrats, but it sounds thin and incomplete to many of the swing voters that left the party in the 1980s, and whom the Democrats must recapture if they want to produce a lasting political realignment.

One of the strangest objects in the outer Solar System was classified as a dwarf planet last week and given the name Haumea. This designation makes Haumea the fifth designated dwarf planet after Pluto, Ceres, Eris, and Makemake. Haumea’s smooth but oblong shape make it extremely unusual. Along one direction, Haumea is significantly longer than Pluto, while in another direction Haumea has an extent very similar to Pluto, while in the third direction is much smaller. Haumea’s orbit sometimes brings it closer to the Sun than Pluto, but usually Haumea is further away.

It may be just a dwarf planet, but I think it’s interesting enough to visit on the Grand Tour. Who knows what we might find on that (probably) icy planet and its two little moons?

Robert Woodhead, self-described Mad Overlord and all-around geek, has posted an amazing amount of detail from his recent experiment in seeing how the Diet Coke & Mentos reaction works in microgravity. It’s a modification of the now-standard geyser-producing demonstration, but with a twist: performing the trick on a Zero G flight and recording it on a high-speed camera. The Youtube video is great, but the expanded description is even better.

Continue reading “Mentos + Diet Coke + Zero G = Best. Experiment. Ever.”

(inspired by Frontalot and Dr. Horrible)

“Almost every week I have to do chores and when I open the closet door, I have this avalanche of plastic bags falling on top of me,” he said. “One day, I got tired of it and I wanted to know what other people are doing with these plastic bags.”The answer: not much. So he decided to do something himself.

He knew plastic does eventually degrade, and figured microorganisms must be behind it. His goal was to isolate the microorganisms that can break down plastic — not an easy task because they don’t exist in high numbers in nature.

Daniel proceeded to use iterated experiments and the good old scientific method to extract the most effective bacteria and determine the optimal conditions for degrading polyethylene bags. The result was an amazing 43% degradation over six weeks, much better than the thousand years it would ordinarily take to break down the plastic. (Be sure to read the whole story for some inspiring bits of detective work.)

The best part?

Industrial application should be easy, said Burd. “All you need is a fermenter . . . your growth medium, your microbes and your plastic bags.”

The inputs are cheap, maintaining the required temperature takes little energy because microbes produce heat as they work, and the only outputs are water and tiny levels of carbon dioxide — each microbe produces only 0.01 per cent of its own infinitesimal weight in carbon dioxide, said Burd.

Well done, Daniel. I hope to see a plastic-bag compost bin on the market in a few years, or at least a Wired How-To on making one for myself. (via Mother Jones)

[1] See my previous mention of homemade aerogels. Kids these days!