Final Project

I decided to put this picture of a ceramic urn into my journal to get some ideas down about the Physics final project. For our video, Justin and I want to create a walk-through on how to make a ceramic piece from beginning to end. This process involves a lot of the physics concepts that we learned over the entire year. For example:
1. Friction keeps clay on the wheel
2. Wheel spins because of magnetic forces
3. Magnetic forces are caused by alternating currents
4. Centripetal acceleration must be zero for clay to be centered
5. When clay falls on wheel it flies off tangent if there is not enough friction
6. Glazing of ceramic piece produces color with pigments
We can probably use some of these concepts and other ideas for our video.
Bonus: Mirror : )

Switches in Circuits

This is a miniature portable key board that can be plugged in and used for sending text messages to friends on the Xbox 360. It draws power from the xbox controller itself and works through the physics concept of circuits. When a button is pushed down, it completes a circuit that then sends an electrical impulse contiguous to a given letter or number on the pad. Each word on screen is created by a complicated set of circuits within the messenger kit. Furthermore, circuits are altered by the addition of a SHIFT button, which can produce capital letters, and a GREEN and ORANGE button. When these buttons are held down, they are able to change what each letter or number does. For example, by holding down the green button and pressing W, the @ sign will appear. This is because the green button + W is a different circuit for the electrical impulse than the letter W alone.

CFL vs. Incandescent

Did you know that the action of switching out an incandescent light bulb for a CFL (compact fluorescent light bulb) in every US household would be equivalent to removing the emissions of 1,000,000 cars? This is possible because of the more energy-efficient design of the CFL. While incandescent light bulbs rely on tungsten filament that uses more energy to produce heat than light, CFLs work using a different design. CFLs are made up of tubes with electrodes at their ends. The electrodes shoot electrons through the argon and mercury filled tubes. In turn, having recieved energy, the gases strike a phosphor coating inside a tube, which creates a fluorescent light. This virtually takes away the heat factor in using up energy. An incandescent light generally produces 15 lumens per watt, while a CFL produces 45 lumens per watt. That is why, when producing the same level of brightness, a CFL only needs a 1/3 of the amount of energy that the incandescent bulb uses.

Gift Cards

Gift cards, along with many other cards used for purchases and identification (like credit cards and security pass cards) use a magnetic stripe (magstripe) to work. A magstripe is made up of thousands of tiny iron based particles that act like bar magnets. These particles are magnetized to face either the north or south pole in order to store information. When you swipe your card, a magnetic reader finds your information and verifies such things as the card's expiration date and amount.

This is a picture of a speaker that uses a variable resistor in the sound knob to control the volume of the sound it produces. The resistance on the electrons flowing through the speaker changes as the knob is turned. When the knob is turned, a strip of metal or other conducting substance is moved, forcing the electrons to travel a longer path than before. According to the resistance equation, extending the path also increases resistance. When resistance is increased, less electrons reach their destination per second and less sound is produced.

The Physics of an Air Filter

This is a picture of an air filter in my house that is meant to capture harmful materials in the air such as dust, cotton, and pollen. The filter is able to do this through the use of technology that is related to what we are learning in Physics right now. Near the front of the filter is a grill, which is called the "corona discharge" and is meant to ionize particles in the air. This electrical field gives extra electrons to the neutrally charged particles in the air. Because dust and other harmful substances are usually large, they are the ones who gain the negative charge produced by the "corona discharge." Further into the filter there is a metal plate with a strong positive charge, to which the now charged particles in the air are attracted to. With most of the harmful materials gone, clean air can flow from the top.

Torque

In the case of a fire, a firefighter would hook up a hose to the valve of this hybrid fire hydrant. He/She would then turn the red wheel to allow the pressurized water in the hydrant to be pushed through the hose and onto the fire. This task would be very difficult without special tools since the wheel's diameter is very large, it is pulled tightly to prevent pressurized water from bursting out of the valve, and is rusty. To turn the wheel, the firefighter would have to exert a significant torque. If the firefighter could not exert enough torque, he/she could increase the lever arm by attaching a clamp to the wheel with a bar attached. The firefighter could then push on the extended bar to turn the wheel, as the force necessary to exert a specific torque is inversely affected by the length of the lever arm.

Torque

Last Friday, we learned the difference between circular motion and rotational motion. While with circular motion we could calculate centripetal forces, with rotational motion we can use an equation to determine torque, which depends on two factors: Force and Lever Arm Distance (T=F*r). In paddling, the more torque you can produce, the faster the canoe will move. In the picture, the measuring tape goes from the handle of the paddle to the typical place where your bottom hand should be. This is effectively the lever arm distance. Paddling coaches say to hold as low as possible on the paddle because as the lever arm distance increases, so does torque.

Impulse

Why is a foam football easier to catch than a leather one? I always had an idea that the foam football was easier to catch because it was softer and easier to grasp, but I now know the physics behind this innate idea. When a football hits your hands, it exerts a force upon you. To stop the football and hold on to it, your hands must exert the exact same force back upon the football to create a net force of 0 N and reduce the ball's velocity to zero. Impulse, defined as the change in momentum of an object, equals Force times time. With this information, you know that an extension of the time of a catch will decrease the force exerted by the ball at any given second. The foam football, which compresses as you catch it, exerts a smaller force over a longer time, while the leather football does not compress as you catch it, and thereby exerts a larger force on your hands over a shorter time period. This is why a foam football is easier to catch than a leather one.

Newton's 2nd Law of Motion

Now that tennis season is finished, I decided to write my journal about the physics involved in paddling, the sport I am doing now. In a race, the speed of the canoe is all important to winning. According to Newton's second law of motion, the acceleration of an object is equal to the net force acting on it divided by its mass. In the case of paddling, the net force on the canoe equals the sum force of everyone's paddle against the water minus air/water resistance. To increase the net force on the canoe, the paddler should be as strong as possible to exert more force on the water, but not too heavy, for as the paddler's mass increases, the boat' acceleration decreases.

1st Quarter Review Journal

For the first quarter at least, Physics seems to be better for me than Chemistry ever was. I decided to choose a picture of an eraser and corrective pen because I know that I need to make mistakes and work hard in Physics before I can master the concepts and succeed. Physics is a very interesting class, and the labs that we do are at the same time fun and applicable to learning the laws of nature. I also enjoy the Physics videos that we watch like Mythbusters and the Japanese game shows, because they show how Physics can be integrated into the real world in new and interesting ways. Though I find Physics interesting, I sometimes have trouble working with its equations; but I know that if I keep erasing and correcting, I will understand them in the end.

Position Graphs

This week, my family bought a new wireless mouse after our old one broke. Though I'm not exactly sure how a wireless mouse works, I think that it is based on the same technology that we used in our position graph lab. A usb receiver works with the laser on the bottom of the mouse in determining the pointer's position. As the mouse moves towards the computer (usb receiver), the mouse pointer moves upward on the screen. In the same way, the mouse pointer movers downward as you move the mouse away from the computer. This also works for moving the mouse right and left. This seems like a good application of Physics in improving technology.

Airsoft Gun Physics

This weekend, I decided to shoot my airsoft gun. Though I was'nt playing against anyone else, I just felt like practicing hitting targets. Like Adrian, my airsoft gun is an aeg (airsoft electric gun) but his is cooler. Even though I have a m4 and he has a G3SAS, our guns use the same principles of physics to fire bb's. When you pull the trigger, the gears in your gun push a coiled spring as far back as it can go and a bb is pushed up into the barrel from your clip by a hop-up system. The spring is then released, propelling the bb at a very fast speed from your barrel at your target. The speed is measured in feet per second (fps). In the end, the velocity of your bb as it comes out of the barrel depends on many factors such as: the quality of your battery, spring, or gearbox, or the size, weight, and type of your bb's.

Newton's Third Law of Motion

Journal 1: On Saturday, Sept. 6, I went to a tennis match between the Iolani Raiders and HBA Eagles. When the tennis ball is hit, Newton's third law of motion is applied. In his third law, Newton states, "For Every Action There Is An Equal And Opposite Reaction." When a tennis ball hits the strings of a tennis racket, the ball reacts by springing forward in the opposite direction. Tennis also can be used as an example for positive and negative acceleration. As the ball comes from across the net, it is moving in the positive direction with a positive velocity. Because of air resistance, the ball's acceleration is negative. At the point of contact between the racket and ball, the ball's acceleration becomes negative, then becomes positive as the ball slows down while moving in the opposite direction at a negative velocity.