# Playground of the Mind with Dan

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## Optical illusions

Many of us enjoy looking at optical illusions, but why do our eyes lie to us????? Although each illusion has it's own reason, and scientists still don't know all the reasons, it comes down to one thing. Our brain makes assumptions. Our brain uses context of our surroundings to make split second assumptions. This is helpful in everyday life and back when we were hunters and gatherers and needed to make split second decisions in the wild. Our eyes don't show us what's really there just what

## DSLR or iPhone Camera??

The selfie is something that has become hugely popular. People are constantly taking pictures with their phones and this has become a common part of our culture. With all these people taking pictures on their phones, the question arises, is it worth it to buy a camera or just use your phone? The major camera type is a DSLR ( digital single lens reflex). The DSLR I use for comparison is a Nikon D80 which is a pretty average DSLR so it will be a good representation of the average. There are man

## Physics of a Hockey Check

The physics behind a hockey check is fairly simple. It is a basic collision. One force, the checker, is coming in with a mass and acceleration, onto and another player with a separate mass and acceleration. As Newton's law states, every action has an equal and opposite reaction. So the player with a bigger mass will be able to absorb more of the hit, and a smaller player, much less so. The Player who was hit will stay in motion unless acted upon by an outside force. A lot of times this is the

## Resonance

Many cultures and spiritual factions speak of the importance of frequencies and vibrations. many cultures believe it plays an important role in nature. Certain frequencies create geometric shapes as the frequency increases, the patterns get more complex.

## 2D Reubans tube.

In physics you learn about waves. However, many people don't realize that waves are every where. A rubens tube is a tube with natural gas pumped through it with holes in the top. when a steady vibration is used on the tube, a standing wave is formed. It has nodes and anti nodes like any wave. When you put a lot of vibrations through, like say music, the effect is very cool. Most rubens tubes are just a linear single tube, in this video however, it goes into 2 dimensions the resul

## The Universe, How Did That Happen??

The Universe is a fascinating topic. How the universe was made can be traced back to many things, I don't wish to offend anyone, but I will not be talking about any divine powers, just some scientific theories. Most Theories start with a big bang of sorts. The big bang is really more of a cosmic stretch of the universe. Most people know about the big bang or at least the basics, so I will proceed to other theories about the origin of the universe. The first theory involves another dimension.

## Tennis

Physics is ever prevalent in the world of sports. Tennis is no exception to that. A tennis racquet, much like a baseball bat, has a sweet spot. A tennis racquet however, has 3 so called sweet spots. One is right by the center, and this is a node. A player will feel little to no vibration when the ball is hit in this spot. There is another sweet spot is at the center of percussion. The COM is located shortly below the node. The third spot is located even below that, and it is at this spot wher

## Water and Sound

The video below shows a very cool experiment. It shows how the flow of water changes when a vibration is applied. water reacts very strangely when it is vibrated. enjoy

## The Physics of Destiny

Destiny is a video game devolved by the company Bungie. Bungie has experience with theoretical physics after they made the Halo series. Destiny is one of the most expensive games ever made, which brings up an important question. Did they do a good job? The first thing to look at is the little details. The capes the shadows, the lighting, and so on. In this, in my opinion, they did a good job. The game looks and feels fantastic. There are many flaws with this game, but all in all, they did a g

## AP Physics C, A New Hope

I am a senior in high school. I enjoy physics. These are two facts about me. I have enjoyed math for quite some time now and the application of math is what really draws me to physics. I am taking AP Physics C because I enjoy a good challenge. I have a thirst for physics that cannot be quenched by any other class. This class offers a unique opportunity to expand my understanding and increase my skill in physics while at the same time makes me frequently consider my decision to take the class.

## Lift Forces

A fluid that flows past a surface of a body exerts a force on it. Lift is the perpendicular component to the oncoming flow, of this force. It is the opposite of a drag force. Aerodynamic lift is different from other kinds of lift. Aerodynamic lift requires relative motion of the fluid. It usually refers to when an object is completely immersed in a fluid. Lift is what makes it possible for a plane to fly. Lift is also used in Frisbees. As man takes to the sky, we owe much to the power of l

## What is Plasma?

Plasma is one of the four states of matter. You have plasma in your light bulbs, TV's, and the sun. Plasma is created by ionization. A gas is heated or put in a magnetic field. Plasma is a good conductor and therefore has a very small electric field. Plasma is the most common state of matter in the universe. It is a very important pat in the fusion of light atoms. Plasma is often confined to a small region for fusion to take place in reactors. Plasma is a key part of solving the energy crisis

## The history of the light bulb

When people think of the light bulb, they just think of Edison. That is not the case. in 1802, Humphry Davy created the first electric light. He heated carbon with a battery until it started to glow. This was known as the electric arc lamp. This invention didn't work because it didn't last very long and was just too bright for an practical uses. In 1840, Warren de la Rue enclosed a coiled platinum filament in a vacuum tube and passed an electric current through it. The design was based on

## Slap Shot

Hockey is a fast paced sport full of physics. A prime example is the slap shot. The slap shot is basically a large rotational force. The player is rotating his body and uses the stick as essentially an extension of his body. You can calculate the force by finding the impulse on the puck. http://www.youtube.com/watch?v=bcielx6_ArQ This is a video of Zedeno Chara at the 2012 all star competition By simple physics equations, we can find out that his stick is rotation at 12.4 radians p

## Compact Discs, aka CD's

CD's are something that everybody has had or has. But for such a universal product, we really don't know how they work... Although the disc looks and feels flat, it actually is quite the contrary. On a CD is a ton of little pits. These pits have binary code in them. Then a Focusing laser goes over the pits, receives the code, and transfers it to a detection circuitry. The digital signal received is then converted to analog form by a D/A converter. The Laser used is a semiconductor laser. T

## Laserzzz

What is a laser you may be asking yourself No? Understandable, but I will tell you about them regardless Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. There are many variations of lasers but all have the same core parts. Those Parts are a medium, two mirrors, and an energy source. Energy from the power source excites the electrons in the medium. The excited electrons produce photons of light. There are two mirrors facing each other in a laser. One of the

## Golf Swing

A golf swing is much like a slap shot in hockey. A good golf swing is vital in the game of golf. A golf swing is almost all rotational energy. A higher velocity means more rotational energy. The more energy in your swing leads to more energy transferred to the golf ball. The more energy you can transfer to ball the farther it will go. The angle at which the club hits the ball is also important. You want the face of the club to be completely flat when it comes into contact with the ball. If

## Gray's Paradox Solved! (Speedy Dolphins)

In 1936, A British zoologist named James Gray was baffled by the speed of dolphins. These dolphins were able to reach speeds of over 20 miles per hour! He examined the dolphins muscles and demonstrated that they weren't built to reach that kind of acceleration with drag. He chalked that up to their skin and that was the accepted answer..... was. It turned out that Gray was wrong. Dolphins are amazing creatures and it turns out, Gray didn't give these water dwelling mammals enough credit!!!! A

## Pinch Harmonics

Guitar players have many techniques in their arsenal. A guitar is a very versatile instrument and has the potential to make many different sounds, few more distinct than the pinch harmonic, also known as pick harmonic, or a squealy. The basic technique behind it is that right after you hit the string, the string hits your finger. This cancels out the fundamental frequency and all overtones, except those that have a node at that location. Overtones that are a multiple of the intended overtone

## Soccer

Soccer, the most popular game in the world, has a lot of physics under the surface. The first is Newtons first law. The law of inertia. The ball stays at rest until acted upon. usually by a players foot. Then it stops only by an outside force. This could be friction from the field, air resistance, or another player. You can also factor in Newton's other two laws as well as momentum and a variety of others. The best physics in my opinion however, is the bending of the ball on a shot, or the

## Bowling

Bowling has been a favorite past time for so many for so long. It is a sport that unites people from all parts of the world. Though the techniques may vary, some more unorthodox then others, some with spin, some with a simple flick of the wrist, the physics behind it is ever present. Most standard bowling balls have weights in them, but there are two major types, symmetric and asymmetric. Though they perform very similarly, the asymmetric weights give the bowlers a little more tweak in their

## Physics of Skyrim (or lack thereof)

Skyrim is one of My favorite games ever. There is a lot of good physics in the game, but that's not nearly as fun as the bad physics. This is what happens when physics goes wrong.

## The Physics of Destiny part 2

Continuing, another important part of the game is the weaponry. To start, there is a weopan class called fusion rifles. The game offers no insight into how these guns work but the only assumption I can draw is that it has something to do with fusion. My theory is that there is some sort of nuclear energy generated by fusion and is somehow controlled and then fired from the wopen. There would be a lot of physics in the charging/splitting of atoms all in a short a series of short bursts. The

## Bass Guitar

The bass guitar, or at least the physics behind it, works very similarly to a guitar. The note that is produced by plucking the string has to do with the frequency. For example, if a string has a frequency of 440 Hz, than that would be an A note. You can change the octave of the note by either doubling the frequency, or cutting it in half. That means that it is still an A if it has a frequency of 220 Hz or 880 Hz. The frequency of the note is determined by a couple of factors. The main fac

## Holograms

Holography is the art of 'lensless photography'. It is typically formed by reflected light captured on film. For example, a laser would hit an object. The object then reflects the light, and the reflection of the light is what is captured on the film. The images from a hologram contains more information than a traditionally photograph. The image is three dimensional and exhibits parallax. Holograms have cool properties that aren't displayed in photos. My personal favorite is that in a transmi

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