DOOOONE :(

Physics is all kinds of things! From pendulums to the speed of light, we learned so much in this class. If i were to google the proper definition of "Physics" I would come up with "The branch of science concerned with the nature and properties of matter and energy," but to  me, it will always be "The best Summer School class ever." We learned sooo much in such a short span of time. We rolled, dropped, shot, threw, pumped, moved, and broke all kinds of items from eggs to rockets and a bunch of things in between. I admit, I had a ton of fun in this class and 6 weeks of physics definitely flew by! I completely understand all of the concepts we were taught in this class and even those crazy equations! You made it really fun and easy to learn everything without rushing us or stretching a lesson longer than needed. 


Everywhere where I go, all i can think about are Physics. Seriously. When i'm on the bus, and it comes to a stop the whole bus whiplashes back and now i know why. Newton's first law: objects in motion tend to stay in motion! Its crazy. I learned all about velocity and mass, even the difference between that and weight because they definitely aren't the same thing! Even learning about acceleration and collisions was fun! The equations with used, DAT VAT VAD and D=VT will probably stay in my mind forever. We learned about things like gravity, which pulls at a force of 9.8m/s^2, projectiles and the rate at which an object would fall, conversions from kilo to centi, to our recent lessons including waves and the speed of light in certain media. 


I can say I liked everything about this class. Even those darn exams and everynight blog posts weren't so bad after all. I loved how the labs were fun and educational at the same time, also that we had many opportunities to work in other groups, and not only ours but those around us. I like how we used the remotes to answer questions and do some review! It really helped before those tests to go over things that we didn't understand and while using them on the test it was simple to just plug in our answers on the remotes. And I especially liked your music playlist! It made it all the better! Also, the short breaks we got between actually learning were good, and the long lunch break we got was helpful because even if we didn't finish at 2:30, it gave us more time to get our food, come back, and then be immersed in physics. 
I know we learned more than the guys next door! haha the ones in back of the boards that is.. But i think we had more fun than either class! I wouldn't change anything about it. :D

A little something from every unit, sorry it's a very bad picture!

refraction!

Refraction is the change in light speed due to change in medium! Refraction is dependent on the speed of light in the medium it's travelling through. We use the equation n=c/v, c standing for the speed of light in a vacuum which is 3x10^8m/s, v for the speed of light in the medium and n for the index of refraction. We used this equation to find the speed of light in air (n air) which is 1, by dividing 3x10^8m/s by 3x10^8m/s (c/n) and since the meters per second cancels out there is no units for the index of refraction. n and c have an inverse relationship meaning as the index of refraction goes up, the speed of light in a vacuum decreases. 

We can apply Snell's Law to refraction, which is n1Sinϑ1=n2Sinϑ2. To determine the direction of the refracted ray we can use our equation and plug in all the numbers we know in order to solve. The pencil goes from air to water, so air's index of refraction is 1 by using the equation n=c/v and dividing the speed of light by 3.0x10^8m/s, then to find the index of refraction of water you use the same equation but instead plug in 2.25x10^8m/s for v and get 1.33. If the angle the pencil is coming at is 60 degrees from the water, Theta1 would be 30 degrees. The pencil is going from fast to slow so n1<n2 and ϑ1>ϑ2.If i stuck my pencil perpendicular to the surface, there would be no bending since that is the normal. The light is coming from the top of the room, so if i use Snell's Law i can find the angle water bends the pencil at! It would bend more to the center or normal so to the left a little. Here's the work! vv 

We can also use Snell's Law to find the critical angle of object that go from a slow to fast medium such as water to air if the light source is coming from the water. This time n1 would be greater than n2 and we'd set it up as sin-1(1/1.3). 

We also learned about light that goes through different shaped lenses. An object in front of a lens in the shape of a long oval with light will send a ray parallel to the ground, then once it hits the lens, it travels towards the focal point on the images side going down. A parallel ray is parallel to the optic axis, meaning that light that hits there, will stay there. The focal ray will go through the focal point and then bend parallel to the optic axis. Light that hits the focal point on the object's side will travel downwards, then hits the normal coming from the lens and travel parallel to the surface. Another ray that hits the center in the middle of the lens will travel down and they will all meet causing the image to be ral and inverted because it shows up upside down and enlarged. I hope that makes sense! :] 

Reflections!

Today we learned about light and reflection. There are two types of reflection, specular and diffuse. Specular (regular) is when light is reflected off of a smooth surface, while diffuse is when it is reflected off of a rough surface. Some specular items include mirrors and smooth bodies of water. The angle of incidence is equal to the angle of reflection so ϑi=ϑr.All the angles are relative to the normal. Some examples of a diffuse surface are paper, cloth, or asphalt. 

Here's a venn diagram of the three primary colors of white light and their mixtures!

Complimentary colors are two colors that when put together, they make white. So for example the complimentary of blue would be yellow. In class we did a lot with the color projectors so for example, there were the words Red, Green, Blue, and Black written in their matching colors, and when the projector shined specific color light on the board there were different results. The red cancelled out with the projected light, but the green shone when in green light because the light needs to be the same frequency to fully blend in. When we were looking in the light spectrums we compared the light in the classroom to the sun's rays outside. The colors were more blended and stronger than indoors.

We used the equation v=fλ to solve for frequencies, wavelength, and velocities of light using 3x10^8 m/s as the speed of light! To find the distance of a light year, we could use the equation d=vt and plug in the speed of light for velocity and convert our time to seconds then multiply. 


Onto more reflection! While doing our lab with the light thingies, we could see the reflection of light rays when directed by different types of mirrors such as a flat one, a concave one, and a convex one. Concave is when it bends inwards and convex is when it bends outwards. When light rays are reflected from a concave mirror, they create a focal point where all the rays meet. Unlike concave, convex mirrors send the rays outwards where they will never collide with each other. The flat mirror caused the reflection to move in a direction with the same angle as it was bent at. Light bounces off of a source so that our eyes can see them, if it is unable to get to the object, you can't see the light reflected off of it!

Unit 10

LIGHT :D

Electromagnetic Waves are those that have transverse waves travelling perpendicular to the energy travelling longitudinally, (like what we did in class with out hands!) these are given off by light. We learned about light and waves today and how light has to strike an object and reflect it back into our eyes. Thats how we see colors and objects! There are two types of light, transparent and opaque (although it is relative). Transparent is when lights allows electromagnetic waves through, not visible to our sight. Opaque light is when electromagnetic waves aren't allowed to go through, thus making them visible to us. For example: Windows. A light year is the time it takes for light to travel for a year, but is measured as distance. The speed of light is about 3x10^8 m/s, faster than the speed of sound which is why there is a loud boom when you break the sound barrier!

More waves!

Today we used the equations V=fλ which is wave speed equals frequency (in Hertz) times lambda (wavelength). We looked at a stretch of string connected to a wave driver and a pulley.By increasing the frequency, you directly increase the velocity, but frequency and wavelength have an indirect relationship meaning as one goes up, the other goes down. We were also able to count the nodes that were unmoving and the antinodes which were vibrating up and down, but the amount of wavelengths is less than both because it is the distance from one spot to another of the same equilibrium. 

An object's "natural frequency" is the frequency an object wants to vibrate at and resonance is the overall adding of wave energies. Sound is a longitudinal wave that needs a medium (what it travels through), without a medium, it cannot exist! The speed of sound is relatively constant. The equation for this is Vs=331m/s+Tc(0.6). 331m/s stands for the speed of sound at zero degrees celsius and Tc is temperature in celsius. Temperature is average kinetic energy, or energy in motion. The speed of sound in the air at room temperature in Hawaii would be approximately 346m/s. Here's how to do it:
Vs=331m/s+Tc(0.6)
85 degrees Fahrenheit=~24.4 degrees Celsius
Vs=331m/s+24.4(0.6)
So the answer comes out to 331+14.64=345.64 or 346m/s!
We also calculated percent error which is ltest-acceptl / accept. So if our experimented speed of sound product was 328 we can set it up like this
l328-346l / 346 = 0.052 so move it over two decimal places and you get ~5% percent error!

WAVES

We talked all about waves and frequencies and defined a whole lot of words today!
A vibration is the back and forth AND BACK motion or "oscillation" which is a cycle of movement. A wave is basically a transfer of energy. What it moves in is called the medium.

We were working a lot with slinkies today because they're a really good example of different sizes and types of waves! There are two types of waves that we created, transverse and longitudinal. Transverse waves are when the energy is moving in the direction perpendicular , and longitudinal is when they travel parallel (in the same direction). So when we were working with the slinkies, to make a longitudinal wave, you would push the slinky forward and pull it back to create a wave. To make a transverse on, you would move it left or right and return to the same spot, this causes the energy to travel side up and down, while it goes to the side until the end of the slinky. The wavelength is the distance or length of wave from two equal spots, usually from trough-to-trough or crest-to-crest. The amplitude would be the distance from the starting point to either a trough or crest!



As you can see in the photo I'm holding the slinky with both hands and having a pretty even curve. The area that is compressed is the part hat bends. It's compressed because that is where the slinky wires come together, and the areas where it's looser is the long end. This is the rarefaction. By using slinkies we can conclude that the tension of the slinky affects the speed of the wave because a higher tension makes the energy move faster. Also that the amplitude of the wave doesn't affect the speed, along with the wavelength because they still end up being the same! The parts that don't move in a wave are called nodes, and the areas that move are antinodes. We used a lot of this equation: V=F(lambda) I don't know how to do the squiggly line...but Velocity equals frequency times lambda!

Another way of looking at waves is to look at the ocean! I learned today that waves do NOT bounce off of each other (even though it may look that way), but travel through them and continue on their merry way! A period of a wave is the time it takes for one cycle to occur, or for it to return to its original spot. A water wave would be an example of a dispersive wave. This is when a wavelength will affect the speed, compared to a non-dispersive wave which is one that has all waves travel at the same speed in the same medium, not matter what your frequency is (like a sound wave). There are also constructive and destructive waves. Constructive are when two waves come together to create a larger one. A destructive wave is when they are opposite, one positive and one negative, and they cancel each other power out to create a flatline.

Yesterday!

We mainly did review, our exam, and building rockets. For building, Juliet and I created a rocket that was about 1 1/2 feet. This is actually our rocket from today, but to get a picture of what it looked like yesterday, here's a description. One 2L bottle with fins half the size, and a very bright nose cone made of thick paper and pink duct tape! Our absolute first parachute was a 7-11 regular sized plastic bag. We cut the handles to make 4 ends to attach the string to. Our parachute seemed to be the right size compared tot he rest of our bottle. The fins were half the size of those in the picture, but the same design. If you looked at it from the bottle cap area, there would be a pocket in the shape of a V sticking out from the bottle. We assumed the air would catch in here, holding it in the air for a longer period of time. This shot up into the air, but not very high having a total of about 3 seconds. Our problem with this one was that we didn't have enough mass in the nose cone to make it shoot high, and also the parachute wouldn't deploy. This caused it to go off it's path and fall to the ground. By the time we had finished and tested this design it was time to return to class.