July 19th, 2012

coalescence cascades

The other day I was wondering… Why does rain not accumulate (‘coalesce’) in the sky, given the distance it falls, to form deadly sheets or lakes of rainwater that could fall in one place as one large mass? I found the explanation that there is a maximum size of droplet that is reached before the droplet begins to break apart again in freefall.

Picture a huge room full of tiny droplets milling around. If one droplet bumps into another droplet, the bigger droplet will “eat” the smaller droplet. This new bigger droplet will bump into other smaller droplets and become even bigger–this is called coalescence. Soon the droplet is so heavy that the cloud (or the room) can no longer hold it up and it starts falling. As it falls it eats up even more droplets. We can call the growing droplet a raindrop as soon as it reaches the size of 0.5mm in diameter or bigger. If it gets any larger than 4 millimeters, however, it will usually split into two separate drops.

On the topic of water coalescence I coincidentally discovered this uncanny video that shows a mind-boggling dance that occurs when a drop of water meets another body of water. The drop only becomes assimilated after a strange interaction that happens too quickly for us to see without high-speed cameras.

Video via 3qd, text above via US Geological Survey.

July 17th, 2012

Solanaceae, where animal and vegetable histories intertwine

The fascinating history of the Solanaceae family of plants. Rishidev Chaudhuri:

Like some eccentric prominent family, whose genius shades easily into the occult, the evil and the mad, Solanaceae, the family of the nightshade (so often prefixed by “deadly”), both contains several of our most ubiquitous food plants (typically of New World origin) and many of the multifarious toxins and deliriants beloved of witches, shamans and poisoners throughout history. The plants of Solanaceae are a dramatic-looking group, full of trumpet-like flowers that open at dusk and branches and stems that curl together like gnarled witches claws. They are also the source of eerie legends and origin myths, as exemplified by mandrake, said to grow from the ejaculate of a hanged man, and whose scream (when pulled out of the ground) will kill everyone in earshot.

To anyone who has ever shuddered at or been baffled by the thought that for most of history the Italians have had no tomatoes, the South Asians have had no chillies and no one in the Old World (including the Irish, the Germans and the Russians) has had potatoes, the gifts of Solanaceae are apparent. These are the bounty of the New World, plants that were brought over from the Americas by European explorers, introduced into their home countries and then spread to the rest of the world (many of the sins of the Portuguese colonists should be offset by their introduction of the chilli to India). Traces of this recency exist on the linguistic map, and several cultures label tomatoes and potatoes as some sort of eggplant or apple1.

While the major Solanaceae food crops that we eat are from the New World, most of the family members used in the Old World were used as hallucinogens, medicines (in small doses) or as poisons (with the notable exception of eggplant). Both tomatoes and potatoes suffered from these associations, and it took a while before people became convinced that they were safe to eat. One is generally not responsible for one’s relatives (except children), but there is some truth to this fear. The leaves and stems of tomato plants are mildly toxic, and potato sprouts can be quite dangerous (in recent years, much of this has been bred out of the plant varieties that we eat, though the same is probably not true for non-mass-market varieties). Once they broke through to acceptance, though, they spread widely and now both are cultivated widely all over the world. Potatoes in particular were an essential new source of cheap calories for the Industrial Revolution and were declared by Engels to be the equivalent of iron for their historically revolutionary role. They are thought to be responsible for a significant fraction of Old World population growth in the 18th and 19th centuries, with the downside that potato crop failures lead to severe famines.

The classical Old World members of Solanaceae are plants like deadly nightshade (belladonna), datura, mandrake, angel’s trumpet and henbane; these are famously the plants of Hecate and the occult. They are striking examples of the weird intersection of the toxic, the medicinal and the religious that characterize our relationship with a number of plants, and of the thin line between the altered states of revelation and transcendent experience and those of poisoning and death.

More at 3QD.

July 16th, 2012

universal incompetence in measuring competence

Another insightful post from Psyblog explains the ‘worse-than-average effect’:

This means that when you’re good at something, you tend to assume that other people are good at it as well. So, when you’re faced with a difficult task that you are good at, you underestimate your own ability.

It doesn’t just kick in when we have special skills, but also when we think that the odds are long, say because the task is particularly difficult. For example Kruger (1999) found that people underestimate their ability at stereotypically difficult tasks like playing chess, telling jokes, juggling or computer programming.

On the other hand they overestimate their ability at stereotypically easy tasks like using a mouse, driving a car or riding a bicycle.

Read further here.

July 16th, 2012

Csikszentmihalyi knows flow

It seems unlikely that a person named ‘Csikszentmihalyi’ might know anything about anything flowing, but I like the summary of his research as posted on Psyblog:

What was this special state of mind that seemed to absorb the whole of your being? Csikszentmihalyi called it a ‘flow state’. It’s the experience of being fully engaged with what you’re currently doing.

When you’re in a flow state:

  • an hour can pass in the blink of an eye,
  • you feel what you are doing is important,
  • you’re not self-conscious,
  • action and awareness merges,
  • you feel in full control,
  • and the experience is intrinsically rewarding.

To create a flow experience, you need:

  • to be internally motivated, i.e. you are doing the activity mainly for its own sake,
  • the task should stretch your skills almost to the limits, but not so much that it makes you too anxious,
  • there should be clear short-term goals for what you are trying to achieve,
  • and you should get immediate feedback on how you are doing, i.e. you can see how the painting, photo, blog post etc. is turning out.
  • From: The Psychology of Flow

    July 9th, 2012

    springtime is here when the snowmelt is increasing

    A report on ‘frazil ice’ and ‘snowcones’, chilly natural phenomena found in Yosemite national park in March and April.

    July 9th, 2012

    tea eggs

    Photo via globetrotterdiaries.

    I just discovered the aggregatator/blog Tasteologie, home to some intriguing and experimental recipes. I have spent and will spend quite a while fishing for ideas here.

    I will share two egg dishes that impressed me. One is the Chinese ‘tea egg’. Wiki:

    Fragrant and flavorful tea eggs are a traditional Chinese food. The original recipe uses various spices, soy sauce, and black tea leaves. A commonly used spice for flavoring tea eggs is Chinese five-spice powder, which contains ground cinnamon, star anise, fennel seeds, cloves and Szechuan peppercorns. Some recipes [1] do not use tea leaves, but they are still called “tea eggs”. In the traditional method of preparation, eggs are boiled until they reach a hardened, cooked state. The boiled eggs are removed from the water, and the entire shell of each egg is gently cracked all around. Smaller cracks produce more marbling when the egg is peeled for eating. The extra water from the boiling should be allowed to seep out of the eggs on its own. After about ten minutes, the cracked eggs are ready to be put into the prepared spiced-tea liquid and simmered at medium heat. The simmering allows the spiced fluid to seep into the cracks and marinate the eggs inside their shells. After about 20 minutes, the eggs and the spiced-tea liquid should be transferred to a glass or ceramic container for further steeping in a refrigerator. For best results, the eggs should be allowed to steep for two days. The dark color of the spiced tea gives the egg a marbled effect when it is peeled to be eaten.

    The other recipe is simply an egg cooked inside a small courgette.


    I would like to try the same but inside a small, white eggplant, like this one.


    Eightball-Zuchinni Egg recipe
    .






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