The End of Physics

Physics is the science behind everything and anything in motion. Objects, particles, waves, shadows, light, rockets and rainbows. It is the explanation of why things happen.

This was a really fun class. It definitely grew on me. The more we learned the easier it seemed to learn. Its like a language, once you pick it up you can understand it better and better with time. 

I managed to learn a lot in this class considering how short it was. I liked how we just got the basics down, so now i have a basic understanding of what physics is. And i like that everything we learned is applicable to the real world. That factor definitely made me more interested in learning the material. I learned about motion and the forces involved with movement,  acceleration and the role gravity plays, and energy. I learned what work is technically. And lastly, I learned about sound and light waves. Throughout each lesson several questions about day to day life we answered. Simple curiosities such as who made up the order of the rainbow - well that is based on the properties of each light wave. How come when your up to you neck in a pool it looks like you neck is missing? Because of the way light bends in different media. 

I learned a lot of important information that i know i will not be soon forgetting. The best part is that i had a fun time learning everything. We had really fun lab activities, and really cool demonstrations. The work load was manageable so the emphasis of the class was learning and understanding, not just striving for A's.

Unit 10 - Electromagnetic Waves

A flat mirror will reflect a virtual image. That is an image where the light rays do not come together. The distance of the object to the mirror will also equal the distance between the mirror and the image. Basically if you stand in front of a flat mirror you will see yourself as you appear.

If we bend the mirror so that it has convex or concave curvature then images become altered. The object is no longer perpendicular to the mirror and in line with the normal. The normal is always perpendicular to the mirror, but the object is not. Now there is an angle between the object and the normal so that bends the image. This is what makes fun house mirrors so fun and Cloud Gate, this giant bean mirror, so eye catching. We are not used to seeing things warped and stretched like they do in these mirrors. That is the magic of mirrors bending images.

Unit 10

Light waves will potentially go on forever. Unless of course it hits a surface. In that case  it will try to reflect if possible. Specular surfaces are smooth like glass or water. If the surface imperfections are smaller than the wavelength of the incoming light waves the light will reflect nicely. But we do not live in a world with tiny imperfections, so most surfaces are what we like to call diffuse surfaces. These are more rough such as roads or fabric. Light is not as visibly reflected on these surfaces.

My disco ball has a specular surface. Actually each mirror is specular and has its own "normal." A normal is the imaginary line perpendicular to the surface. The angle of reflected light depends on the normal. According to the law of reflection the angle of incidence, or incoming light, equals the angle of reflecting light. A disco ball reflects lights in so many directions because each little mirror making it up is positioned with different "normals." 

Unit 10 - Electromagnetic Waves

Imagine everything you know and recognize as a color actually being several waves reflecting off of a surface and bouncing back to your eye balls for you to perceive. Now that's what color is. When you see red, all the other light waves are being absorbed by the object except for red light. The red light waves reflect and bounce off for you to see. Each color has different wave characteristics such as: wavelength, frequency, and energy. Red has higher energy and wavelength. Since wavelength and frequency are inversely related red has a lower frequency. Violet has high frequency and low wavelength and energy. There is something called an electromagnetic spectrum that displays they colors in order of lowest to highest frequency. When ordered like so, the colors make a rainbow pattern.

Unit 9 - Waves

I learned the physics behind the waves of the ocean. When it comes to water, a longer wavelength has a faster velocity. So those two are directly related. When wavelength directly affects the speed of the wave this is called dispersive waves. Non-Dispersive waves travel at the same speed in the medium regardless of frequency. For example, sound waves are non-dispersive. 

When water is deep the velocity of the wave can be faster, and if the water is shallow, the velocity will be slow. Therefore depth, and the topography of the floor affect waves in so many ways. How they break, where they break, size and speed. For example lets say there is deep water and a wave is moving with great velocity. If all of a sudden the water gets shallow, the base of the wave will slow down but the top part of the wave remains at a high velocity because of inertia. When this happens eventually the base of the wave can't keep up with the top, so the top falls over thus creating a wave.

Unit 9

Today we learned about waves. Waves are all around us, in the ocean, in the football stadium, any sound and light. A wave is a disturbance or oscillation in space and time. Think of it as a wiggle in time and space. There are several properties to a wave, such as frequency. Frequency is the number of cycles that pass in one second. Cycles are measured by wavelength which is between two consecutive identical points of a wave (crest to crest, trough to trough, etc.) We use controlled frequencies to create different waves and make radio possible. Each radio station is represented by a number because that is the frequency of that radio wave. For example 93.9 has 93.9 waves pass in one second. This is frequency 93.9Hz or Hertz, the unit for frequency.

Rocket Launch: Day 2

     We started launching with our old model, small fins and long skinny nose cone with a weight inside. Our launches were averaging three seconds and not doing very well. We made bigger fins and a new nose cone. We made our cone out of sturdier material. Before it was manila folder so we made our new one out of a cereal box. It was wider and shorter. Our launched were improving already but we cut more off of our fins and nose cone to make it smaller. We also cut off the top of our bottle so our parachute could fit into the top of the bottle as well as the nose cone. When it was only being stuffed into the nose cone it was getting packed too tight and wouldn't release. Overall our rocket was doing well even though we didn't get to achieve the ten seconds of flight time. One time the parachute stuck to the tape on the nose cone. One time the string of the parachute got wrapped around a fin so it didn't open up properly. We encountered a new problem with each launch and I think if we had more launch time we could have eventually fixed every problem. The hardest thing was getting the parachute to launch. I think what worked best was having a nose cone on loosely and a piece of the parachute sticking out. Once the rocket started to fall air could fill up this little piece of parachute like a pocket and the rest of it would open up. The hard part was finding a balance. We wanted it to stick out enough to do the job, but if it was too much it would create drag and slow down the initial velocity.
     We were shooting our rocket around 60 psi. That seemed to be when there weren't that many bubbles pumping into our rocket anymore. We filled it up almost half way with water, so just under one liter.
     I learned that the rocket was sensitive to physics, and one adjustment made all the difference. Weight made a big difference when we did not have weight in the tip of our nose cone it didn't work at all. The whole time though we had to consider the risk of weight over design. A more solid nose cone was risky of adding weight. Some risks payed off and some didn't. It really was an experiment. I found that despite the heavier mass, the cardboard nose cone worked impressively better. Since it was stronger it could take the hit better. The force of impact crunched he tip of our nose cone upon landing, but it saved our rocket from being damaged.