02 MAR 2019 by ideonexus

 Entropy in our Everyday Lives: Active Stability

Because things naturally move to disorder over time, we can position ourselves to create stability. There are two types of stability: active and passive. Consider a ship, which, if designed well, should be able to sail through a storm without intervention. This is passive stability. A fighter jet, in contrast, requires active stability. The plane can’t fly for more than a few seconds without having to adjust its wings. This adjustment happens so fast that it’s controlled by software. Ther...
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24 DEC 2016 by ideonexus

 Unlike Physics, Biology Can't Ignore Information

Physicists love to think about systems that take only a little information to describe. So when they get a system that takes a lot of information to describe, they use a trick called 'statistical mechanics', where you try to ignore most of this information and focus on a few especially important variables. For example, if you hand a physicist a box of gas, they'll try to avoid thinking about the state of each atom, and instead focus on a few macroscopic quantities like the volume and total en...
Folksonomies: physics biology information
Folksonomies: physics biology information
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02 SEP 2016 by ideonexus

 Teaching Temperature

Outside Temperatures. Place a thermometer outside a window so students can make daily calculations and keep a chart reporting the actual temperature and the temperature change from the previous day. Students will see that the change can be a negative number without the temperature falling below 0—an often-confusing concept that is clarified by these observations. An achievable-challenge extension could include barometers, and students who need more advanced work can learn how negative—or...
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30 JAN 2015 by ideonexus

 The Sensation of Pressure

We feel pressure on our skin, when we place our hand over the outlet of a bicycle pump, for example, as a kind of springy push. Actually, pressure is the summed bombardments of thousands of molecules of air, whizzing about in random directions (as opposed to a wind, where the molecules predominantly flow in one particular direction). If you hold your palm up to a high wind you feel the equivalent of pressure - bombardment of molecules. The molecules in a confined space, say, the interior of a...
Folksonomies: perception senses pressure
Folksonomies: perception senses pressure
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24 JAN 2015 by ideonexus

 Q

The hypothesis of {108} abstraction says that every living creature is characterized by a number Q which is a measure of the complexity of the creature. To measure Q, we do not need to know anything about the internal structure of the creature. Q can be measured by observing from the outside the behavior of the creature and its interaction with its environment. Q is simply the quantity of entropy produced by the creature's metabolism during the time it takes to perform an elementary respons...
Folksonomies: complexity quantification
Folksonomies: complexity quantification
  1  notes
 
24 JAN 2015 by ideonexus

 Hawking's Equation

awking has written down an equation which looks rather like Planck's equation. Hawking's equation is S = kA, where S is the entropy of a black hole, A is the area of its surface, and k is a constant which I call Hawking's constant. Entropy means roughly the same thing as the heat capacity of an object. It is measured in units of calories per degree. A is measured in square centimeters. Hawking's equation says that entropy is really the same thing as area. The exchange rate between area and en...
Folksonomies: physics equation
Folksonomies: physics equation
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