Showing posts with label nature. Show all posts
Showing posts with label nature. Show all posts
Thursday, December 22, 2011
Polar Sea Ice Coverage
I added a page illustrating the current polar (i.e. Arctic and Antarctic) sea ice overage to my blog. It was originally located elsewhere. The information is provided by the National Snow and Ice Data Center. The diagrams show the ice concentration in the polar regions, the regions covered by polar sea ice and how the area with an ice density of 15 percent or higher varies.
Wednesday, November 30, 2011
Some like it hot
The current prediction for climate change by 2100 is that we are heading for an increase in temperature of 6 Kelvin (6 degrees Celsius or 11 degrees Fahrenheit). And here are some short National Geographics videos outlining an increase in temperature of
1 through 6 Kelvin
| Could Just One Degree Change the World? |
| 2 Degrees Warmer: Ocean Life in Danger |
| 3 Degrees Warmer: Heat Wave Fatalities |
| 4 Degrees Warmer: Great Cities Wash Away |
| 5 Degrees Warmer: Civilization Collapses |
| 6 Degrees Warmer: Mass Extinction? |
Saturday, November 26, 2011
The deadly touch of the ice stalactite
An ice stalactite or brinicle (brine icicle) is the undersea equivalent of a stalactite or icicle. They form beneath sea ice when a flow of extremely cold, saline water is introduced to an area of ocean water.
The video is the first ever recording of the formation of an ice stalactite and not only shows its beauty but also its deadly power. More at the BBC’s site.
| BBC Nature: ‘Brinicle’ ice finger of death filmed in Antarctic |
The video is the first ever recording of the formation of an ice stalactite and not only shows its beauty but also its deadly power. More at the BBC’s site.
Tuesday, November 22, 2011
Hall effect for pedestrians
Professor Bowley explains the Hall effect, which involves electric current and magnetic fields.
| Hall Effect - Sixty Symbols |
Monday, November 21, 2011
“Made Easy” Errata
Sunday, November 20, 2011
How to properly arrange arrays of wind turbines
Researchers at Caltech say that the power output of wind farms can be increased by an order of magnitude (i.e. at least tenfold) simply by optimizing the placement of turbines.
Modern wind farms usually employ propeller-like horizontal-axis wind turbines (HAWTs). The design has the disadvantage that the wake generated by one turbine can interfere with neighboring turbines thereby considerably reducing the energy that is produced. Therefore the individual turbines are placed farther apart than the obvious requirement of their blades not being able to touch dictates.
Bigger blades and taller towers allow to use more of the wind and to do so at heights where gusts are more powerful but this results in higher costs, more challenging engineering problems and a larger impact as bigger and taller turbines generate more noise and are more dangerous to birds and bats.
The solution the researchers suggest is using vertical-axis wind turbines (VAWTs) (think of egg-beaters sticking out of the ground) can be positioned very close to one another and optimize their arrangement. Having every turbine turn in the opposite direction of its neighbors also increases their efficiency. Here is a video illustrating how the arrangement looks like:
In the following video, John Dabiri, the Caltech professor of aeronautics and bioengineering who suggested the design of the wind farm, himself explains what fish schools have to do with it.
More on this:
Modern wind farms usually employ propeller-like horizontal-axis wind turbines (HAWTs). The design has the disadvantage that the wake generated by one turbine can interfere with neighboring turbines thereby considerably reducing the energy that is produced. Therefore the individual turbines are placed farther apart than the obvious requirement of their blades not being able to touch dictates.
 |
| Alltwalis Wind Farm, Wales by Statkraft on Flickr License: CC BY-NC-ND 2.0 |
Bigger blades and taller towers allow to use more of the wind and to do so at heights where gusts are more powerful but this results in higher costs, more challenging engineering problems and a larger impact as bigger and taller turbines generate more noise and are more dangerous to birds and bats.
The solution the researchers suggest is using vertical-axis wind turbines (VAWTs) (think of egg-beaters sticking out of the ground) can be positioned very close to one another and optimize their arrangement. Having every turbine turn in the opposite direction of its neighbors also increases their efficiency. Here is a video illustrating how the arrangement looks like:
| Caltech Field Laboratory for Optimized Wind Energy (FLOWE) |
In the following video, John Dabiri, the Caltech professor of aeronautics and bioengineering who suggested the design of the wind farm, himself explains what fish schools have to do with it.
| Caltech Researchers Find Wind-turbine Placement Produces 10-fold Power Increase |
Human Evolution and Ancestry
Now comes a post that to some people people may be a red rag. It is two video about human evolution and how we all are descendants of Africans.
For the above video I use LiveLeaks because the youtube video is not available in Germany due to the German pain in the ass called GEMA.
| Human Evolution Made Easy |
For the above video I use LiveLeaks because the youtube video is not available in Germany due to the German pain in the ass called GEMA.
| Human Ancestry Made easy |
How evolution works
The following two videos from the Made Easy series explain how evolution works. The first one deals with natural selection, as this mechanism is central to evolution – note that the full title of Darwin’s famous book is “On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life,” while second one presents evidence for the actual process of evolution.
Note that the chicken displayed as a thumbnail for the second video is very fitting. Believe it or not: chickens are the closest living relatives of the much-feared T. Rex (so if someone asks how T. Rex steaks may taste like, the best guess is “tastes like chicken”).
| Natural Selection Made Easy |
| The Theory of Evolution Made Easy |
Note that the chicken displayed as a thumbnail for the second video is very fitting. Believe it or not: chickens are the closest living relatives of the much-feared T. Rex (so if someone asks how T. Rex steaks may taste like, the best guess is “tastes like chicken”).
The Age of Our World Made Easy
This Made Easy episode deals with the question how old Earth is and the scientific evidence that it was not created around 4004 BC.
| The Age of Our World Made Easy |
The Story of the Earth Made Easy
This Made Easy video explains how scientific understanding of geological formations and the processes leading to them grew over time.
| The Story of the Earth Made Easy |
Saturday, November 19, 2011
The History of Our Universe Made Easy
Two videos from Potholer54 on the history of our universe and how scientists little by little learned about it.
| The History of Our Universe Made Easy, Part 1 |
| The History of Our Universe Made Easy, Part 2 |
Cosmic rays causing global warming
A video by potholer54 on fact (what a certain scientific article actually says) and fiction (what certain blogs report it says).
| Are cosmic rays causing global warming? |
Thursday, November 17, 2011
Simply Explained: 2011 Nobel Price in Physics
Physics Nobel Prize 2011 - Sixty Symbols: “Studying supernovae and the accelerating universe - and a bet over a bottle of whisky. It's our take on the 2011 Nobel Prize in Physics, won by Saul Perlmutter, Brian P Schmidt and Adam G Riess.”
| Physics Nobel Prize 2011 - Sixty Symbols |
The Beatles in theoretical high energy physics
The Beatles cannot possibly have anything to do with the field of theoretical high energy physics, can they? Wrong you are! ☺
The following is a small excerpt from “General second order scalar-tensor theory, self tuning, and the Fab Four” by Christos Charmousis, Edmund J. Copeland, Antonio Padilla, and Paul M. Saffin. You are definitely not expected to be able to understand the formulas (leave alone what Einstein has to do with the indices on the right not occurring on the left).
There you have it: The Fab Four in physics.
The following is a small excerpt from “General second order scalar-tensor theory, self tuning, and the Fab Four” by Christos Charmousis, Edmund J. Copeland, Antonio Padilla, and Paul M. Saffin. You are definitely not expected to be able to understand the formulas (leave alone what Einstein has to do with the indices on the right not occurring on the left).
 |
| John Lennon, Paul McCartney, George Harrision, and Ringo Starr |
There you have it: The Fab Four in physics.
Tuesday, November 15, 2011
Searching Eos
Scientists have come up with the theory that the current Earth-Moon system is not a direct result of the collision of a Mars-sized object with the young Earth but that for some time there have been two moons that eventually and considerably after the collision themselves collided to form our current Moon. Chances are that NASA’s GRAIL mission will be able to answer the question whether Eos actually existed.
“Eos?” you ask? I must admit that this is just my idea for naming this former celestial body; however, in Greek mythology, Eos is the sister of Luna and the goddess of dawn. The name seems to be perfect as Luna is associated with the Moon and the lost celestial body dates back to the dawn of Earth’s history. Moreover, in antiquity Eos was not associated with an actual celestial body.
“Eos?” you ask? I must admit that this is just my idea for naming this former celestial body; however, in Greek mythology, Eos is the sister of Luna and the goddess of dawn. The name seems to be perfect as Luna is associated with the Moon and the lost celestial body dates back to the dawn of Earth’s history. Moreover, in antiquity Eos was not associated with an actual celestial body.
| ScienceCast: Did Earth Have Two Moons? |
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