Physics Review and Reflection

Overall I really liked this class, it was always very fun and entertaining. We learned a great deal too, 10 units of physics in 6 weeks. We went from knowing nothing to knowing all about kinematics (the study of motion), acceleration, forces of gravity, momentum, sounds, and light. I never knew about Newton's 3 Laws of Motions before, the first one states all objects will tend to stay at rest or in motion unless acted upon by an outside unbalanced force, the second one saying that force equals to mass times acceleration, and the third stating that with every action there is a reaction. It was amazing learning so much in so little time.
Mr. Blake made things very easy to understand. I liked all his examples and ways of teaching. Like when we learning about colors of light and couldn't believe that red and green makes yellow, he proved it to us by turning off all the lights and windows and using projectors to shine the colored lights on the screen. It was really cool because with every light color that would go onto the screen we would play a song that would go with the colors. Like when he showed green he played a kids song, I think by Kerby the frog singing, "It Isn't Easy Being Green." When he put the red and green on the screen, it shocked all of us by making yellow and when he stood in front of the lights, he casted two shadows, one that was a bright red and one that was green. Once these three rasta colors went on the screen, he changed the song to reggae. It was amazing to look at and really helped us learn about the colors of lights.
From this class, I feel like I can apply everything to physics basically. It's actually really sad how often I do it. Just last week on wednesday after class, my friends and I went to the beach in Waikiki. When we were driving around the area looking for parking, we were on the street and almost ran right into a bus when switching lanes. After all of us panicked for a little while, I then applied physics to the situation. I told them how if we were to run into that bus because it has a bigger mass, it has more inertia and would take out our car easily. I even explained to them what inertia was, the objects ability to stay in motion or at rest. After explaining, my friends just kind of looked at me but I'm glad I know now what happens in these kind of situations.

This picture is one of my friend and I sitting in the truck on our way to Waikiki.

Unit 10: Electromagnetic Waves, Color, and Light Properties

Light rays can create two different kind of reflections, specular (regular) and diffuse. Light rays can change directions from hitting surfaces, but they are always straight lines. A specular reflection is when a light ray hits a smooth, reflective surface like mirrors or such. Diffuse reflections happen when a light ray hits a bumpy, scratchy surface such as screens or doors. Specular reflections reflect the light rays following the rule of the reflection with the light rays being the same angle as the initial light ray to the normal on the opposite side of the normal. Diffuse reflections don't follow these rules and with these bumpy surfaces sometimes don't even reflect off the light rays. That's why projectors shine their light onto screens with diffuse surfaces so it doesn't reflect off the screen and is able to show what is to be seen.

Unit 10

In class we learned about the primary colors of light. it was very surprising to me finding out that red, green, and blue were the 3 main primary colors. Usually (or at least what I learned in art class this last semester), the 3 primary colors are red, yellow, and blue. Learning the color wheel today felt so new to me because everything was so different. The new 3 complementary colors are yellow (mix of red and green), cyan (mix of green and blue), and magenta (mix of red and blue). At first I was barely able to believe that these colored lights were able to make these colors when put together, but then in class, with the help of 3 projectors, we were able to see all the complementary colors. When we put all the colors together though, you get white. We found out that white is actually a reflection of all the colors. We found in the shadows from the light to be a black color, this is the color that is formed with an absence of light. It was amazing to understand how the colors of lights work with or without each other.
This picture below is one I took of a sunset. I found out that skies are normally blue because of the scattering of that color in the upper atmosphere and also because there is a less amount of other colors like red, yellow, and green up there too. Around sunset, since this is when the sun goes through the most atmosphere to get to where we are, with more matter around the more the color changes. Sunsets are beautiful and it was cool to know about why it changes and why it is the color it is.

Unit 10

Today in class we learned about electromagnetic waves, these are the waves emitted by light.  There are two types of light sources, ones that emit it and ones that reflect it. With visible light, we are able to see colors, which include red, orange, yellow, green, blue, indigo, and violet. White and black aren't really colors, white reflects all of them while black absorbs it. That's why when you wear a black shirt, you get hot more easily standing out in the sun rather than a white one because it attracts the light. Objects can be transparent or opaque to light. When it is transparent, the electromagnetic frequencies can go through the objects like windows. When it is opaque, the electromagnetic frequencies cannot go through the object like doors.

I like waking up early to watch the sun rises, that is my favorite part of the day. I love watching the way the sun peaks over the mountains (I live in Manoa) and starts creating a shadow onto the valley. This shows how opaque the mountains are in relativity to the air and the clouds. Although the clouds can sometimes create a little shadow, it is not as dark compared to the one of the mountain because some light is still able to pass through it.

Unit 9: Waves & Sounds

Waves are mediums disturbed by vibrations, there are two types of different waves. There are transverse and longitude waves. Transverse waves are waves that has their energy moving perpendicular to their velocity. Longitude waves are those with energy moving side to side with their velocity. Transverse type of waves include ones like the ocean, longitude are ones that happen more so in springs, slinkys, and such. In transverse waves, the area where it is tight or compact are areas of compression, the areas where it is looser and not as compressed are called rarefactions. An example of a transverse wave would be like when people line up, and move side to side. When my sister had her baccalaureate this past year at central union church, we stood outside the church and lined up as a family to take a picture. When taking it my mom accidentally tripped and hit me, which made me hit my sister, and my sister hit my dad. With this movement, and then stepping back into place, we make a transverse wave.

Unit 9

Waves are mediums disturbed by vibration, they basically look like squiggly lines. Waves can come in many forms, like the ocean waves, radio frequency waves, or spring waves. They are found everywhere in so many situations. Waves can go at different velocities and can have different lengths. The wave length and velocity have a directly proportional relationship so that with an increase in one, the other also increases. This can occur with ocean waves. Living here in Hawaii, we are a little island surrounded by miles and miles of water so most of us know a lot about it. With little swells coming through the ocean, maybe from a small storm, those swells can come to us a day later. With big waves, like the tsunami one that hit Japan, it can take only a matter of hours for the huge wave to make it's way out over here because with it's bigger wave length, the velocity of the wave is very, very fast, sometimes hundreds of miles per hour. The bigger the wave, usually the more dangerous. Like when pro surfers go out on waves that are 30 feet high, it's super dangerous, life threatening because with all the water moving so fast, the wave can drown a man by pulling them under at a very high speed. The reason why waves break at the shore and not really in the middle of the ocean is because the rocks and sand at the bottom affect how they break. If you were out in the ocean and two swells / waves were coming towards each other, both of the waves once hitting would make a wave the size of both put together because both of their energy is put into that one part of the water. It's important knowing these facts about waves, especially living in Hawaii.

Rocket Building

When Kim and I were launching our rocket for the first couple times, it wasn't working so well. We had big fins and a skinny manilla folder cone attached to our bottle rocket. It would only stay in the air for an average of maybe 3 seconds, barely. To help lighten the mass to keep the rocket up longer, we would cut down the fins by an inch and then prepare to launch. We learned that big fins are only good to a certain extent, when it comes to being too long where it's weighing the rocket down and is unnecessary, it is useless.

Still after cutting and cutting down the fins, we then tried using less water. We figured with more air inside, the more the pressure can build and get a higher psi. With a higher pressure inside the rocket, the launch would go off with a higher velocity, going higher into the air.

After getting wet from the wet ground and the water accidentally getting poured on our cone, it got really muddy and a little soggy, it wasn't too sturdy so we came back in the class room to make a new cone. Having no more folders, we used a honey bunches of oats cereal box for the cone. It felt so much more stable than the other cone. As we launched, it's time in the air passed doubled from 3 seconds to 6.75 seconds. We figured out that it was the cone that was holding our rocket back.

We tried really hard to get our parachute to come out and tried many different folding techniques. We tried one that I found on the internet where I fold the rectangular chute the long way, then into many triangles. We tried to just loosely fold it and stuff it into our cone. We tried leaving a little piece or pieces of the chute out of the rocket so hopefully the air would pick it up and throw off the cone once at the top. However through all these tries, we couldn't get a successful parachute. The technique that probably worked the best though was to leave a little piece of the plastic parachute outside the cone, but when we would do this, we noticed the velocity of the rocket going up was slower and the rocket would go less high.

This applied to physics with the variable of air resistance, or the force of friction with the air. When launching up the air would push against the rocket, because with an upwards force against the air, the same force is coming back onto it, this is due to Newton's third law of motion, every action has a reaction. With air resistance, we would have to make the shape of our nose cone very pointed so it can cut through the air easier, having less friction on it to slow it down. Also with earth's acceleration of -9.8 meters per second per second, we really needed a nose cone because gravity is already pulling down on our rocket, we don't need air resistance to slow it even more.

Rocket Building

In class we are working on water bottle rockets. These are made from 2 L bottles with water inside being pressurized from air being pumped in, which should have a psi around 60. My partner Kim and I brought in two 2 L bottles of soda for the rocket body, cereal boxes to cut out the cardboard for fins, a manilla folder to make the nose cone, a plastic garbage bag to make the parachute, kite twine to connect the nose and parachute to the rocket, and duct tape to piece everything together. We first picked the bottle with the smallest mass to keep whole because we figured with a smaller body mass of the rocket, it will be easier to keep in the air without the weight pulling it down. We then decided on making a very slender, long nose cone from the folder. With a longer cone, the more narrow it is and fights less air resistance helping the rocket to go faster. We cut out 4 fins, all very long and thin to help keep the rocket straight in the air and also long to have less friction with the air going on. After being cut, we taped the fins with duck tape to make it more stable, the less shaky it is the more likely it will stabilize the rocket and keep it from breaking. The parachute was very tricky, we are still trying to learn how to hold it because during the launch it didn't open. Hopefully with using even more tips, we can keep our rocket in the air for more than 10 seconds.

Unit 8 Continued

Today we learned about power, it is the rate of which work is done at. It is measured in work per time, in units of joules per seconds, and is represented by a Watt. The difference between work and power is that work is the change in energy while power is more so the rate of energy (dealing with measurements of time).

Around Christmas time, my dad puts out incandescent decoration lights in our drive way and leaves them on all for all night. Even with these these Christmas lights going, we still use the same ones inside, maybe not for all night, but probably around for a good couple hours before we go to sleep. If the ones outside are harsh, hot, incandescents while the ones inside are flourescents which save a bunch of electrcity, the incandescents by morning time should have done the most work compared to the flourescents. The energy used by these light bulbs is much greater than that of the energy efficient ones. The power also is very high because even though it is going on throughout the whole night, a long period of time, a great amount of work is being done. Even though the inside lights are only on for a couple hours, because they are such energy savers, they don't use as much power.

Unit 8: Work & Energy

Work (W), is the only change in energy (delta E). Work = Force • Distance which is also Work = Newtons • Meters. Energy / work is measured in Joules ( J). The law of conservation of energy says that energy cannot be created or destroyed, it only changes form. In other words the sum of your energy coming in is the same amount as the energy going out. There are two different kinds of energy, potential and kinetic. Potential energy is the stored energy in an object, it is based off gravity and the height you are from your equivalence point, it is based off of positioning. Kinetic energy is moving energy, it is based off of motion. For example, if plumeria flowers were falling off a plumeria tree onto the ground, the energy they would have while still connected to the branch of the tree would be all potential, because it is all stored energy and is not yet in motion. Half way to the ground the plumeria's energy would still have the same amount (because energy is never lost and is always conserved) but just be a different type, half potential and half kinetic. Right before the plumeria touches the ground, all of it's energy would be kinetic because it is at its greatest movement. As the plumeria drops from the height of the tree, it loses potential energy and gains kinetic energy.

Egg Drop

My partner for this egg drop was Sho Matsumoto. The day before it took place, we were coming up with ideas. The requirements were that we can't use parachutes, the volume must be at most 35 cm • 35 cm • 35 cm, and the capsule must be ready to drop within 60 seconds of obtaining the egg (which means it must be ready in a minute after getting your egg).

An idea we came up with was to have a bungee rope attached to our egg. We got many, many rubber bands, cut them with sisscors so it was basically a rubber string, and triple knotted them all together. We guessed how much we should use because we didn't know how long it would stretch out to after being dropped. I brought in a tissue box because we weren't planning on dropping the egg just by itself attached to rubber bands and from it we took out all the tissues and wrapped it around the egg. The rubber bands would lessen the acceleration of the egg and therefore making the impact less great. Instead of dropping it from a 3 story building, by the time the rubber band would stretch all the way out and be at it's maximum, the egg would have slowed down to maybe only around half a story. From then once it slowed down we would release the cord and let it fall, at least we would of decreased the drop height of the egg.

In class, after talking to Mr. Blake we found out that our capsule didn't meet the requirements. Our bungee cord although could be held in the fist of your hand, it can also be several meters when stretched out (not meeting the 35 cm measurement). He told us that we could still test our bungee cord but we have to make a different system for the egg to depend on without the rubber bands. Using Matt's wrestling helmet, we placed towels in the curve inside of it and then stuffed our tissue box in. It looked like an upside down helmet with a tissue box in it. We came up with the idea really fast because we used most of our time trying to make the bungee jump.

As we dropped our egg off the third floor of Bishop, surprisingly our egg survived. It's landing from the helmet seemed to have made it bounced and I guess with all the cushion (tissue and helmet) supporting the egg from taking in all the force helped a lot. When watching the video of our egg test, we could see the helmet cushioning the drop really well, it spread out over the floor and took the impact. This helped lessen the force because it had a greater contact time (change in momentum = average force • change in time). After testing this capsule, we then used the bungee cord which didn't really work because we made the rubber bands too long. By the time it hit the ground, the cord could have still been stretched even more. I was really happy with our surviving egg that lasted through two drops but something that would definitely help the bungee idea would be to make our cord a lot shorter. I actually really want to see the bungee again with a shorter cord, I'm sure it would work a lot better.

Unit 7

Momentum can be passed from object to object, however it is always conserved. This means that the amount of momentum going in is the same amount of what is coming out of the system. We learned about inelastic and elastic. Totally inelastic collisions is when colliding objects stick together and become one. Elastic collisions would be when objects are still separate after the collision. An example of a totally inelastic situation would be like the time I was running after my friend on the beach. It was night time and I was chasing after her to splash her with water, she was slower than I and I jumped on her to chase her down. If she was object 1, moving at a velocity slower than mine, and I was object 2 running in the same direction as her except with a higher velocity, as we would collide I would give her my momentum after us sticking together through me jumping on her. With equations using and knowing our masses and the velocities, we would be able to find the momentum. And through knowing the force and already knowing the momentum, we can find the time.

Unit 7: Momentum, Impulse, & Collisions

In unit 7, we focused in on the momentum of a object or objects. Momentum is the product of mass and velocity, so  p = m v  ( p : average momentum, m : mass, v : average velocity). The unit it is measured in is kg (m / s). We learned that momentum is always conserved and the sum of momentum in is = to the sum of the momentum out. Force = change in momentum • time, this means that with more contact time, the force is also changed. For a cheer bonding last year, my team was in the pool and was doing some stunting, which is when we do tricks with lifting people up. After some shoulder sitting, we were able to make a 4 person sit. Using the heaviest and strongest mass at the bottom we built up our tower getting higher and lighter. The person with the most mass was at the bottom because inertia is directly proportional with mass. After learning about momentum, I found that the technique we used helped us because with a smaller mass, velocity is inversely proportional to it so the velocity would be bigger. It would help us to push people up on to higher shoulders.

1st Semester Review

I learned so much in this first semester, from accuracy and precision to speed and velocity, from acceleration through projectiles and free falling objects to Newton's 3 Laws of Motion. In total, we were taught around 6 Units of Physics. The first one dealt with just the basic vocabulary we would need to learn, such as periods: "T" - the time it takes for one complete cycle to occur, accuracy: closeness in relations to the expected value (target), precision: how close a group of values are to each other, qualitative (appearance / descriptive) and quantitative (deals with measurement) observations, and conversion factors.

In Unit 2, we got into motion, we were taught about scalar: value with magnitude (how much of something you have), vectors: value with magnitude and direction, displacement, the distance you are from your original / starting spot, distance: the total amount you traveled, speed: how fast you're traveling (distance over time), velocity: displacement over time, and instantaneous speeds: the speed of an object at any given instant. At first, understanding this unit was really hard for me. I had trouble understanding the difference between vector and scalar units. The only difference between the two is that with one, direction matters. This was important to understand because through this it affects distance and displacement and also speed and velocity. Although challenging, through examples I got it.

Unit 3 was a continuation of kinetics except added in a new variable of acceleration, which is the change in velocity over time. Also through this unit, we were introduced to some equations (d, a, t, / v, a, t, / v, a , d,) to help us solve for certain variables like distance, acceleration, time, velocity, and the initial velocities, when having the given in some problem. Real life situations dealing with acceleration would be ones like with cars and such.

Unit 4, taught us the Vegas rule which is what happens on the x - axis stays on the x - axis and what happens on the y - axis stays on the y - axis, this rule helps with 2 dimensional things. This is when there are changes happening on both the x and y axes, so there are horizontal and vertical changes going on, like for projections. SOHCAHTOA was also taught to help us with these projects, through there diagonal path we could make right triangles and with using the angles and velocity, we could find both the horizontal and vertical velocities. In this unit, I really liked the way this break down and forming of the right triangles were taught to us. Mr. Blake would use his methods of the Bureku and Ukerub techniques which he supposedly learned from his "master", it was very entertaining and helped to maintain what we had to learn easier because it was more memorable.

Unit 5 taught us about Newton's 3 Laws of Motions and frictional forces. The first law, also known as the Law of Inertia, states that objects at rest or in motion will tend to stay at rest or in motion unless acted upon by an outside unbalanced force, inertia is directly proportional to mass. The second law says that acceleration of an object is directly proportional to force and acceleration is inversely proportional to mass. The third law says that with every action there is a reaction to it. For example, in class when Mr. Blake got on a skate board and Sho stood in front of him, when they both pushed each other, it really helped my understanding that they are both putting the same amount of force on each other, the only reason why one accelerates faster is because one has less mass.

In Unit 6, we just applied acceleration to Newton's Laws. We went more into how with bigger accelerations there are smaller masses, and with bigger masses there are smaller accelerations. We were taught how to find the accelerations with pulleys (which change the direction of tension), and how to find the tensions. The way it was taught, with the reggae voices made from our teacher was good because it made me remember "da whole ting" from how he would say it.

Unit 6

In Unit 6, we learned about friction. Friction is a force (push or pull) that opposes motion or impending motion. This kind of force is a contact force which means that it has direct contact between two objects. Friction is an important factor to consider in physics especially with Newton's 3 Laws of Motions. The force of friction can affect the acceleration of an object. For example, with the Inertia Law, saying that an object will stay in motion if in motion or in rest if it's at rest, won't apply so well if friction is involved. A ball can't keep rolling if it's on a surface of sandpaper as easily as it would on slippery ice.

An example of friction, looking at it on bigger terms, would be like the ocean. When your riding a boat, you want to go on a smooth sailing day, while the water is calm and not too bumpy. Therefore, if the water is so smooth, your boat can glide over it easily. If you go when all the waves are out, when its stormy or rough waters, it's very dangerous to go out to sea because with the waters so rough, it can toss your boat and keep it from moving. This would be like the boat going over a surface with friction (rough water), which slows the boat or stops it from moving.