## Friday, December 9, 2011

### Witricity

A team at MIT decided to use magnetic resonance to achieve the wireless electricity goal. It was prompted because one of the researcher's wife's phone kept having a low battery beep during the night and it was waking up. To solve this problem, wireless electricity was born. 2 coils are used, just as the charge pads, but they work by different methods. Here, the coils are manufactured to resonate at the same frequency, allowing them to transfer energy very efficiently. This is very similar to an opera singer breaking a specific glass or aligning the frequency of you legs with a swing to get it started. When the frequencies are in sync, then the energy is transferred. The magnetic field caused by the first coil will only induce a current in the coil that has the same resonant frequency. Therefore, the energy is non-radiative because it doesn't do harm to anything with a different resonant frequency. Going back to the opera singer, only 1 glass will be shattered, while the rest will just sit there unharmed. Witricity holds many possibilities like eliminating cluttersome cords. Think of an airport with free wi-fi and witricity; there would be no plugs to fight over. This technology has already been proven to work, so hopefully in the next few years it will become commercially available and eventually the norm where we can look back at cords and laugh.

Here is a demo of Witricity and also an explanation.

http://www.ted.com/talks/eric_giler_demos_wireless_electricity.html

## Wednesday, December 7, 2011

### The Fourth Dimension Explored

When considering dimensionality, it is easiest to first consider the dimensions that we have "access" to - we are "trapped," after all, in the 3rd dimension, and thus cannot physically visualize any higher physical dimensions, but we can certainly think about them using the following analogy. Let's consider a 2-dimensional world, that for the purposes of this explanation we'll call "flatland," in which objects have only length and width, but no height at all. Now, consider what would happen if a 3 dimensional object were to enter this 2-dimensional world; it would exist in flatland in only 2-dimensions, and the residents of flatland would only be able to view the object in two dimensions as it passes through the plane. This must be utterly odd to flatland-ers, as they essentially see an object appear out of nowhere, rapidly change shape, and then disappear again into the nether.

Now, with this analogy in mind, let us consider the other direction of dimensionality - the 4th physical dimension. It is obviously not possible for us to visualize the 4th dimension, but think about it in the following way:

The 0th dimension, we can think about, consists of only a single point. Extend that point into a line, and we have 1 dimension - length. Take that line segment and move it at 90 degree angles to itself, and we have a 2 dimensional square. Take that square and move it at 90 degree angles to itself and we have a 3 dimensional cube, complete with length, width, and height. A cube physically has vertices all of angle 90 degrees, with lines of equal length. When this cube is visualized in 2 dimensions, as on a piece of paper, not all of the angles are conserved, and all of the lines are not of equal length. This is part of the penalty associated with losing a dimension. Now, what would happen if we were to take this 3 dimensional cube and carry it into the 4th physical dimension, in other words, connect each of its vertices at 90 degree angles of the same length? We cannot physically comprehend this object, called a 4-dimensional hypercube, or tesseract, in our 3-dimensional world, but we can visualize it's shadow in a 3-dimensional world, as seen above.

### Physics of Javelin

## Tuesday, December 6, 2011

### The Physics of Judo

## Monday, December 5, 2011

### The Physics of a Rube Goldberg Machine

## Sunday, December 4, 2011

### The Physics of Dogs and Cats Lapping Water

However, one researcher realized that cats utilize a completely different technique. Instead of forming a scoop, cats will ever so slightly bend their tongue tip back and touch it to the surface of the water. Inertia and the cohesion of the water molecules enables the liquid to be drawn up into the cat’s mouth in a column. At a certain point, the force of gravity becomes greater than the force of the inertia. At the instant where the strength of these forces switch, the cat knows instinctively to close its jaws and capture the maximum amount of water. A cat can lap water 4x/sec and never ceases to close its mouth at the exact same moment. The MIT researchers confirmed this by building a robotic tongue and altering its lapping speeds. (http://www.youtube.com/watch?v=ht9bPJDlRFc&feature=related)

In May of 2011, another study was published that confirmed the cat data, but also showed that dogs do actually utilize the same method as cats. An x-ray video was used to illustrate this point, and it was found that the only reason dogs are so much messier at drinking than cats is because they stick their tongues into the water further down than cats. (http://www.youtube.com/watch?v=12paEIC7BkU)