Why does sprinkling a little water enable sand to stick together sufficiently to enable the building of sandcastles? The cohesive forces produced are strong enough that one can build a tower that is 2.5 meters high on a mere 20 cm base. A group of scientists have looked into this and come up with an explanation. [Read more…]
From all early reports, it seems like the Mars Curiosity landing went off perfectly. So many things could have gone wrong, and almost any one of them could have resulted in disaster. [Read more…]
On Monday, August 6 at 1:30 am Eastern Time in the US, the Curiosity rover will land on Mars. The gravitational field on Mars being roughly twice that of the Moon, its atmosphere being so thin, and Curiosity being so big, all posed immense challenges to the scientists and engineers who had to figure out how to gently drop the vehicle onto the surface. It does not help that Mars is so far away that there will be a time lag of 14 minutes for communications to get from Earth to the spacecraft and vice versa, meaning that no adjustments can be made from Earth once the descent begins. [Read more…]
Stephen Colbert has more on the Tony Robbins fire-walking fiasco in which many people got burned while trying to show the power of mind over body. I had no idea that people pay thousands of dollars to attend his programs. These things seem to be quasi-religious in nature and it is curious the kinds of things that people put their faith in. [Read more…]
When presented with news and other information, we have both visceral and cerebral responses. The visceral comes from the emotional reaction and occurs immediately and almost spontaneously while the cerebral response arises from our intellectual reaction involving conscious thought and takes a while to kick in. [Read more…]
I wrote recently about University of Pennsylvania researcher Uri Simonsohn who has developed a new, but yet unpublished, statistical technique to detect whether raw data have been improperly massaged to get positive, publishable results. [Read more…]
I have recently been on a Sherlock Holmes kick, watching episodes of the old British TV series starring Jeremy Brett and then reading the stories again since some years have passed since I last did so. The latest one was the 1994 episode The Last Vampyre based on Arthur Conan Doyle’s short story The Adventure of the Sussex Vampire in which a case is brought to Baker Street about a possible vampire in the county of Sussex. Holmes, the epitome of rationality and scientific deduction, dismisses out of hand the idea of vampires and has no doubt that there is a perfectly ordinary explanation for the reports. [Read more…]
We have all observed what happens when water drops fall on a hot skillet. Rather than simply boiling off, they skitter around for awhile before disappearing in a puff.
This phenomenon is due to something called the Leidenfrost effect. If you place a drop of water on a surface, it gets flattened and just stays there due to gravity. But when placed on a surface whose temperature is higher than the boiling point of water, a thin layer of water vapor forms almost immediately that partially insulates the drop from the hot surface and also raises it off the surface, making it almost spherical again as well as reducing the frictional forces on it, enabling the drop to move around freely in response to the turbulent air currents that surround it. [Read more…]
There has been a sharp rise in the number of whooping cough cases in the US this year, with the number of cases expected to be the worst in five decades, although it was hoped at one time in the 1970s that it might be entirely eradicated. [Read more…]
Apparently the people who attended the Tony Robbins program paid anywhere between $600 to $2,000. The blame for those who were burned during the fire-walking climax is being placed on them, saying that they must have been ‘out of state’, which is apparently the technical term for not having the proper mental attitude. Even some of those who were burned say that it was their own fault for not having the right frame of mind despite Robbins’s careful preparation. Some of them repeat it even after getting burned. [Read more…]