Jillm

=__Jill M's Physics Page__= include component="comments" page="Jillm" limit="10"

**__ Agents of Climate Reflection __** In the article //Agents of Climate// the author talks about solar radiation which is electromagnetic raditaion energy from the sun. Electromagnetic energy is viewed as a stream of photons that behave as either waves or particles. These photons enter the Earth and is absorbed by the atmosphere, the interactions between the photons and atmospheres gases bring about climate. The ozone is responsible for the absorptioin of these photons and adds a small amount of heat to the atmosphere, therefore, atmospheric temperature can be explained by the emission and absorption of radiation. This emission and absorption can be illustated with a tub of water with several different drains and faucets (each a different size so there is different flows going in and coming out). If one of the facets increases the amount of water it inputs, and the size of the drains didn't increase, the water level would rise until it reached a new equilibrium. Same with if the size of a drain increased but the faucets still input the same amount of water, then the water level would decrease. So to determine Earth system budgets we have to determine the present level in the system, the sources, and the sinks. With any two you are able to determine the third. This is what allows us to determine the amount heat transfer from the sun and in our atmosphere.

**__Scientific Imagination Reflection__** In the article //Scientific Imagination,// the three authors discuss how it is hard to describe certain aspects of science because there is no way of actually seeing them. For instance, you can't really see electromagnetic waves, we can only imagine that there are invisible waves constantly moving through space. Trying to picture electromagnetic waves would be like trying to explain a rainbow to a blind person. We only see the beautiful colors, but if you really try to describe what a rainbow is, it's an "intensity of radiation as a function of angle under certain weather conditions." Overall I think the authors are trying to say that scientists have a different sense of imagination as well as a different outlook on what beauty really is.

__**Firing Projectiles Reflection**__ The height of where you fire a projectile from affects how long it will take to hit the ground because the higher up the object is, the more time it is going to take to reach the earth. It depends upon the objects velocity (distance over time) so if it is a greater distance it will take a longer amount of time. For distance, the projectile will go a farther distance the higher up it is because it has more time to move a farther distance and doesn’t hit the ground right off. The horizontal speed affects the time it take the projectile to hit the ground because the faster it is going horizontally the longer it will take to slow the object down and have gravity pull it to the earth. Without any horizontal speed gravity would pull the projectile down right away. With more horizontal speed the projectile will travel farther because once again gravity won’t pull it down right away and will have more time to move horizontally before hitting the ground. The vertical speed of a projectile will affect the time it takes to hit the ground because if you shoot an object up, it has to travel upward until it reaches a point of no velocity and then travel back down to the earth. If you shoot it straight down, it will take less time because it doesn’t have to travel upward first. The vertical speed affects the distance it travels because as you tilt a gun, it causes the projectile to curve upward, which causes it to be in the air for a longer amount of time and making it travel a farther distance.

__** Calorimetry Lab Reflection **__ The advantages of heating up paraffin until it melted would be that we could take the actual temperature of the paraffin rather than the water that the paraffin filled test tube was in. This would make our calculations more accurate. The disadvantages would be that not only would you have to find the temperature of the paraffin, but also the water it was in because you would need that data to measure how much heat escaped to the water, calorimeter, and stirring rod. You would have to take more measurements and do more calculations.

__**Energy Reflection**__

The two rules of energy are “energy is conserved” and “energy always goes from more useful to less useful forms.” Theses rules apply to our collisions lab because first in the collisions lab we were trying to prove that law of conservation of momentum was correct. From the lab we saw that this law was true. We were able to calculate the momentum values before and after the collisions and their numerical values turned out to be very similar, and this proved that the energy from one cart was being transferred to the other. Work was being done on the first cart (when it was being pushed) which created kinetic energy. That energy was then transferred to the other cart as the two carts collided and overall the original energy created was conserved. This lab applied to the second rule of energy because eventually both of the carts stopped. They couldn’t keep moving forever. This is because some energy escaped into the atmosphere as friction, sound, or heat. Once in the atmosphere the energy created by the carts can’t really do anything. Both rules applied to the roller coaster lab as well. We measure the potential, kinetic, and mechanical energy at the 30 different points on the roller coaster. From the top of the roller coaster to when it came full cycle the amount of mechanical energy (potential energy + kinetic energy) was pretty much the same, proving that energy had been conserved throughout the roller coasters cycle. The roller coaster cart gained a lot of potential energy as it went up the ramp, that stored energy then turned into kinetic energy as it went down the first big drop, but the cart wouldn’t just keep moving around and around the track. The ramp to pull it back up to the top was important because just like the colliding carts some of the energy escaped into the atmosphere and that energy is no longer useful in making the cart of the roller coaster move.

**__Kinetic Energy, Heat, and Temperature Reflection__**

Matter is made up of many atoms or molecules, most of which are moving in some way depending upon their state (solid, liquid, or gas). Matter has kinetic energy due to the random movement of the molecules. When kinetic energy of the molecules increases, the matter becomes warmer; if the kinetic energy decreases then it becomes cooler. Temperature is related to the motion of molecules in matter, but it’s not a measure of the total kinetic energy of all the molecules in a substance, just the average kinetic energy in that substance. The energy that transfers from one object to another always goes from warmer to cooler. The temperature difference between the objects is called heat. Matter can contain energy, but it does not contain heat. Heat flows in relation to temperature differences, or kinetic energy differences. The motion of atoms in matter causes matter to have kinetic energy. Temperature is used to measure the average kinetic energy an object of matter has. When the temperature between two objects differs, energy transfers from the warmer object to the cooler one, and this is called heat.

= __Work/Energy Reflection__ =

Work is the amount of energy put into or out of a system and is equal to the quantity of forces times the quantity of distance. Where work is done there is an application of force and the movement of something because of that force. When something has been acquired that allows a system or object to do work then it is called mechanical energy. For example, when we dropped the pendulum, as we pulled the pendulum back and then dropped it, it was gaining force from a gravitational pull which allowed it to do work (or swing back and forth). Mechanical energy can be both potential and kinetic. Stored energy that has potential for doing work is known as potential energy. For example, a coiled spring has potential energy because if it is released then it will spring and the result will be a form of work. Until the coiled is released then its energy is just being stored. Kinetic energy is the energy of motion and it depends upon the mass of the object as well as its speed. The kinetic energy of an object in motion is equal to the work required to bring it to that speed or slow it down from that speed. Even with all the different forms of energy and work, the law of conservation of energy states that energy cannot be created or destroyed, but it can be changed from one form to another.

__System Reflection__
According to physicists, a system is any object or ser of objects we wish to consider, which may interact with each other. This definition differs from my original thought of a system, because I thought a system was a group of objects that interact together to produce some sort of change.

The concept of a “closed” or “isolated” system (such as a sealed jar) does not let mass enter or leave the jar, because outside forces can’t influence the inside and what goes on inside the jar can’t escape, so mass would be conserved inside that jar. In a closed system the total momentum can’t be conserved because forces such as friction and gravity do influence a system. However if we were to measure the momentum of two object right before and after a collision (before forces such as friction and gravity really influence the objects) it can be seen that momentum really is conserved in that brief moment.


 * __Clock Lab Reflection__ **

** Independent reflection: **   One lab report will be turned in for each group. In addition, each student must complete   // independently //    a reflection addressing the following questions: 1. How was the process of designing and testing a clock similar to the scientific method as discussed in class? The process of designing and testing a clock was much like the scientific method in a sense because we used many of the steps as guidelines for the lab in order to find a clock that worked. First, as part of the prelab, we predicted which variables we thought would have an affect on the frequency of the clock. Then we had to design the clock by experimenting with those different variables and seeing which variables affected the frequency. With the data we collected and patterns we saw from the experiments, we then had guidelines for how to make the clock that worked. 2. How did it differ? The clock lab differs from the scientific method because normally facts are used to help find patterns in an experiment. In this lab however, it was more of a guess and check trial each time we tested different variables rather than using facts we knew about clocks. 3. What "steps" in the scientific process were present and which were missing? The steps in the scientific process that were present were making predictions, making observations, conducting experiments, collecting data, and noticing patterns. The only step that I thought was missing was making an actual hypothesis. We made preconceptions about what would affect the clocks frequency, but we never made an actual written out hypothesis for which clock design we thought would work. 4. Was there a part of the activity that is not a part of the scientific process? The only part of this lab that wasn’t really a part of the scientific process was the fact that we did guess and check for finding the right design for our clock, but that could just be considered a type of experimenting.

The link to this lab is below with the other links.

__Reflections__ ||
Review questions; 8/31/09 7. Hypotheses, theories, and predictions are essential to the scientific method because if no one ever made predictions or educated guesses about why things happen in nature then there would be no reason to test those hypotheses. With no reason to test and experiment things then theories would never form since theories become theories by being proven experimentally correct many times. 8. An observation is something we notice about nature from our five senses. An experiment is when we change something in nature and observe the outcome from the change. 9. The scientific method should maybe be called a scientific cycle because the word method makes it seem more like you have to follow the method in specific steps; however you can really jump into any step of the method and eventually you will go full cycle through all the steps. ||
 * 6. In the scientific method you come up with a hypothesis, make a prediction, observe and collect data, and identify patterns. A hypothesis is an educated guess about why something occurs in nature. Then predictions are made to explain why that hypothesis occurs. To test those predictions, experiments are conducted in order to collect data and provide proof that the hypothesis is correct. If it is proven correct serveral times, then there is a pattern.

Reflection on Scientific Method; 8/29/09 Reflectoin on Wikispaces; 8/28/09 ** || 2. Outside of school I have access to the internet at my house. 3. I feel wikispaces will be a helpful tool for the class by providing a website that will be accessable from home as well as having things organzied in one space. ||
 * According to the author of the article about the scientific method, the method is a process to help answer questions about the world around us. The cycle of coming up with a hypothesis, making predictions, observations, doing experiments, and collecting data is not necessarily always done in that order. It doesn't matter where scientist start in the cycle because eventually it will take you all the way around the cycle again. Generally, scientists observe something in nature and try to come up with a specific reason of why that is occuring. Once a pattern in noticed, scientists will often begin to make a hypothesis, or educated guess, for its happenings. If the hypothesis is proven correctly many times, a theory develops. That theory could then bring upon new questions about nature which would then start the cycle over again. ||
 * **__Reflections I__
 * 1. I have never used wikispaces as an online tool, but last year I used a blog in several classes.

__Links__
[|Hartford School District] (Check here for important announcements) [|Hyperphysics] Clock Lab Report Collisons Lab Report Roller Coaster Lab Calorimetry Lab