This video is a great optical illusion:
Just watch the video intently without moving your head or your eyes, and when it instructs you to “look away”, look at something else. I found it particularly creepy to look at the back of my hands.
Month: July 2007
Ten Politically Incorrect Truths(?) About Human Nature
See this intriguing post, which as the title states, is a bunch of very politically incorrect “truths” about human nature. I have a feeling that the author has only presented one side of the argument in many cases. In other words, I feel that, at least in some cases (most notably #6 the Trivers-Willard hypothesis), unproven theories have been presented as facts without presenting the arguments or evidence against them.
Notwithstanding the lack of rigor in separating facts from theories, it still makes for very interesting reading. At the very least, these are all “plausible” theories, and do have a possibility of being true. For example:
Men strive to attain political power, consciously or unconsciously, in order to have reproductive access to a larger number of women. Reproductive access to women is the goal, political office but one means. To ask why the President of the United States would have a sexual encounter with a young woman is like asking why someone who worked very hard to earn a large sum of money would then spend it.
Read the full article. Certainly worth it. You don’t have to believe it all, but think about it…
Would a candle burn in zero-gravity?
Image by: Matthew Bowden www.digitallyrefreshing.com
Before you see the answer, think about this for a while? Assume that you are in space, and you are surrounded by an earth-like atmosphere – i.e. 20% oxygen and the rest mostly nitrogen. Would a candle burn? Why, or why not?
The Straight Dope has an answer. Apparently, astronauts in the space shuttle did an experiment to check precisely this:
The space shuttle astronauts brought a couple along on a mission last summer and lit them inside a sealed chamber having an earth-type atmosphere. (This is not something you would want to do in the open space shuttle cabin, where for obvious reasons an exposed flame is on a par with leaving the front door open.) One candle burned for about two minutes, the other for 20 seconds. Then–here’s the vindication you’ve been waiting for–they snuffed. The flames were weak, spherical, and pure blue.
As you realized and your earthist friends obviously didn’t, in a zero-gravity environment you don’t have convection. Convection is the familiar process whereby heated air over a candle flame rises, carrying smoke and waste gases with it. Cool, oxygen-rich air rushes in to replace the departing warm air and in the process keeps the flame going. Convection works in normal gravity because warm air is less dense and thus lighter than cool air and so rises above it. But in a weightless environment the exhaust gases basically hang around the candle flame until all the oxygen in the immediate vicinity is exhausted, at which point the flame goes out.
The full article has more interesting things to say on this topic.