Chinese Yo-Yo's

So today, I went to a celebration of sorts for chinese culture and language at the student center. One of the booths that they had was to try your hand at playing with the chinese yoyo. I noticed that it was a rather peculiar object to be working with. The goal was to take a string connected to two sticks and place it in between the two large parts of the yoyo. The center was made of smooth metal so that the string could slide easily between it. With a quick roll on the ground to get it spinning, you had to lift it up and begin whipping your hands back and forth in order to keep it spinning. Much easier said than done. Not only did you have to whip it, but you had to keep it balanced on that one point where the string came in contact with the yoyo. I immediately noticed that this was very odd. In order for the yoyo to spin smoothly, the center had to have low friction. But in order for it to spin at all it needed to have relatively high friction. This interesting conundrum made the yoyo hard to handle. However, the trained performers could even build enough friction so that the yoyo could climb up the string nearly vertically. I on the other hand, couldn't even manage to get it spinning. Oh well.

Mirage thingy...

The way this interesting device works it by using the two nearly identical mirrors placed on top one another. The position of the focal points of the mirrors are very important. For the top mirror, the focal point is near the bottom and the middle of the bottom mirror. For the bottom mirror, the focal point is hovering right in the hole of the top mirror. That way the light emanating from the object goes out in all directions and reflects off of the top mirror. These rays then reflect directly downward and hit the bottom mirror. From there, these rays are reflected up towards the hole in the top mirror and converge. One interesting thing to note is that the mirrors end up inverting the image as pointed out by the reversed direction of the arrow in my diagram.

To infinity and BEYOND!!!!

Ok well, apparently the blog I did on the weekend did not get posted, so here I go again.
Today's topic is about space travel and another documentary I saw on TV. It talked about the huge expanse of space and different ways in order to more efficiently get people into space and beyond. Currently, we use billions of dollars in order to turn stored energy into heat energy and do work through chemical reactions. But there could be other methods of getting people into space using some physics, some imagination, and some imaginary particles. The first idea would be to create a giant space elevator connected to the ground. This way all we would need to do is use electricity to pull up a giant room of people into space. We are getting closer to developing cords that are strong enough to withstand the velocities of a rotating planet and the space elevator would be perpendicular to the planet to reduce tension. Another idea is to create a space ship with huge sails, like thousands of miles in area, and using laser batteries on the moon to push the ship through space. Photons from the light actually can exert a force onto an object in space and a huge sail could collect this force and translate it into forward movement. Another idea is to use the idea that because super dense materials bend space-time, we can create a super dense material to pull one part of space closer to the ship and therefore reduce the time it would take to travel such a distance. This is somewhat analogous to instead of walking to a chair, using a lasso and pulling the chair closer to you. Instead of traveling faster to the chair, you are reducing the space between you and the chair. The fourth way to increase space travel dramatically would be through the use of an imaginary particle called tachyons. Tachyons are particles that work sort of opposite to normal particles. According to Einstein's equations and theorems, in order for an object to reach the speed of light, it would need infinite mass. However, tachyons have what's called "invisible mass", so instead of the speed of light being a maximum speed limit, it's actually a minimum. If we could turn a space ship into a tachyon like object, it would effectively become invisible to space time in terms of mass and travel at speeds faster than the speed of light. It's just too bad that tachyons violate the laws of conservation of energy, causality, and almost every other physics law known. Hahahaha, a man can dream can't he?