Week of March 22, 2010

If I could go back in time and talk to myself about one concept that would make it easier to learn in the future, I would talk to to myself about work-energy bar charts. First, I would tell my past self that an energy bar chart represents a process that occurs to a system. I would also tell myself that in order for work to be done there has to have been an external force.

Second, I would tell myself that it is important, when making bar charts, to get the labeling at the top right. That way anyone trying to read your bar chard can understand it. Ki+Ug,i+Us,i+W+Kf+Ug,f+Us,f+(delta)int. This all means initial kinetic energy+ initial gravitational potential energy+initial elastic potential energy+ work+ final kinetic+ final gravitational potential energy+final elastic potential energy+ the change in internal energy. Thirdly, I would tell my past self that when you add up the initial energy and the work it should equal final energy. If the final state has more or less total energy than the initial state than positive or negative work must have been done by an outside force, so you should draw a bar in the work column. The number sentence should always be equal.

Fourthly, i would explain energy transfers to my past self. Energy transfers is when you have one type of energy in the before section of your energy- bar chart and another type (but the same amount) of energy in the after section of the bar chart. For example, if the initial state of a bar chart is a marble is high up in a marble ramp [friction free] , it might have 3j of gravitational potential energy, and the final state is it moving (it is almost at the bottom of the ramp) it may have 3j of kinetic energy. no work was done, the energy was just transfered. The night that we practiced doing bar charts with the money examples is a good thing to show my past self. Those helped me understand the whole work section of the work-energy bar charts.

this link explains work-energy bar charts:

http://www.physicsclassroom.com/CLASS/energy/u5l2c.cfm

Week of March 1, 2010

If I could travel back in time and talk to myself about energy and systems, I would first show my self the elephant video. The elephant video helped me understand the different types of energy, how it was transfered, and when the system has these types of energy. The first type is Kenetic energy, I would tell myself that the system has this type of energy when it is accelerating. Then, I would say that gravitational potential energy was when something was at the peak of falling or about to fall. I would show myself Mr. Finley dropping a dictionary. Next, I would tell myself that Elastic potential energy was when something had the power to stretch another thing, like when Aage flung the chalk at the classroom door using a rubber band. Then i would look at the problem with the girl pushing the box on a color changing floor to help me out with the last energy form. To help me learn to identify the things in a system I would talk to myself about all the things that are affecting it, because anything affecting the system cannot be in the system. Then i would ask myself if the system has gravitational potential energy. If it did I would tell myself that I then needed to include the earth in my system. for initial and final states i would try to explain to myself that there are normally two choices for initial and final. For example, when Mr. Finley was dropping the dictionary the initial state could be when it was on the ground and then the final would be when he was holding it. Or, the initial could be when he was holding it and the final would be when the dictionary was in mid-air. It all depends on what kind of energy you are trying to explain that your system has. And for calculating work, I would yell at myself, "YOU CANNOT HAVE CENTIMETERS IN YOUR NUMBER SENTENCE!" because I forget that every time.

Week of February 1, 2010

Comparing and Contrasting Inner and Outer Planets!

There are two different groups in the solar system, the inner planets and the outer planets. the all orbit the same sun, are named after Roman mythology, and have all been explored by a spaceship/rocket. The inner planets are Mercury, Venus, Earth, and Mars. They are close to the sun and are on the inside of the asteroid belt. The inner planets are also called the terrestrial planets because they have a solid surface and are made of iron and nickel and other heavy metal. These planets have little or no moons. The outer planets are Jupiter, Saturn, Uranus, and Neptune. They are far from the sun and are on the outside of the asteroid belt. The outer planets are called the gas giants or the Jovian planets, they are called this because they are composed of gas and have a liquid core. All of the outer planets have rings (even if they are not very noticeable) and many many moons.

The project where we searched up all of the patterns and relationships between the planets helped me understand this concept well.

Week of January 18, 2010

This week in science class we continued our study of Astronomy. In the beginning of the week we learned about direct and indirect light. Direct light is at a perpendicular angle , is smaller, and stronger. Indirect light is more spread out and has less strength. We also learned that we only see fifty percent of the moon, and no more than fifty percent is lit up. We see the moon phases because the moon revolves and rotates around the earth. This week we also learned the terms solstice and equinox. A solstice is when the sun reaches it's highest point (summer solstice) or lowest point (winter solstice) in the sky at noon, marked by the longest ( summer) and shortest (winter) days. This takes place on June 27 and December 27. An equinox is the time and date (twice a year) at which the sun crosses the celestial equator, when day and night are of equal length. This takes place on September 22 and March 20. Later in the week we took a quiz (ahhhh!) and watched a video. In the video David pushed a rolling bowling ball with a hammer to make it move in a circular shape. This brought us to the study of why the earth orbits the sun or why the moon orbits the earth without crashing into it. There are several that need to happen to get something to orbit another thing. First, the object or satellite has to be in motion. (Initial Velocity) If the initial velocity is too small it will crash into the object it is orbiting, but if it is too big the object that is orbiting will fly away (escape velocity). Second, Distance effects the amount of initial velocity necessary to orbit. The farther you are from the object you are orbiting the less initial velocity needed to put in orbit. But the closer you are to the object you are orbiting the more initial velocity needed to put in orbit. Lastly, the arrow direction (direction of velocity)should be perpendicular to the object you are orbiting. to learn this we practiced on our two imaginary planets Turtle and Juego!

Week of January 11, 2010

This week in Science class we took the placement test for honors science. It was two days long. When we weren't taking the test we were learning about seasons. We came up with four hypothesis' for why we have seasons:

1.) Mark- depending on how long the sun is out during the day.

2.) Mickey- depends on where we are around the orbit compared to the sun (if we are close to the sun it is summer)

3.) Emily- it has to do with the tilt of the earth.

4.) Jackie- it depends on the direct and indirect rays.

One by one we tried to prove them wrong. We used the simulation to discover that when the earth is farthest away from the sun it is summer. So Mickey's hypothesis is wrong. We thought about Mark's hypothesis and concluded that his was wrong because the seasons changing is the cause and the change in how long the sun is out is the effect. He had it the other way around. So that left Jackie and Emily. Their hypothesis' were correct. The final answer to the question WHY DO WE HAVE SEASONS?is:

We have seasons because the angle of the tilt of the earth makes direct and indirect light and we are revolving and rotating around the earth, so different parts of the earth get different kinds of light and that is what makes the seasons change.

We also learned five important facts about seasons;

1.) The earth is tilted and stays in that one tilt.

2.) We are revolving and rotating around the sun.

3.) The hemispheres face the sun at different times.

4.) The light is direct and indirect.

5.) Some places don't get much light at all. (Alaska)

Week of January 4, 2010

This week in science class we learned about Astronomy. We learned that the moon revolves and rotates around the earth. We also learned that rotating means changing in orientation but not position and revolving is a complete turn or change in position but not orientation. I learned that the moon and the sun rotate counterclockwise and that it takes 29 1/2 days for the moon to go through all of it's phases. I made the phneumonic device; Nanny Wilson Froze Watermelons For Willie Till Winter to help me remember the phases of the moon. The phases of the moon are New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, and Waning crescent. These phases keep repeating. Lastly, we started making force diagrams for the earth in relation to the location of the moon and sun. This lead us into learning about the tides on earth. The moon pulls on the surface of the earth and since the surface is mostly ocean it pulls the ocean and creates tides and waves. It is important to know these things if you want to be an astronomer, or are interested in anything that has to do with the different waves and tides of the ocean.

Week of December 14, 2009

This week during Science I learned more about forces. i learned that the earth applies more force on a heavier object, but when you drop the two they hit the ground at the same time. We also talked more about the greater the force that you have the greater the acceleration of an object. And the less the mass the greater the acceleration. I also learned that when two forces are balanced, there is no acceleration. The object is either not moving or moving at a steady rate. An object is always moving at a steady rate, even if it is a steady rate of 0 miles per hour or meters per second. We also talked a lot about friction and what a world without friction would be like. You would not be able to stop driving or to stop sliding unless you crashed. You would not even be able to start running because in order to start you have to use friction to push your feet off the ground. We learned about Newton's Third Law. When Kathy pushed on Laura and they were on carts, Laura and Kathy both moved. We also tested this on springs. What we learned from this was that even if an object is not pushing back, it is pushing back and that every object returns the same amount of force that is pushed against it.

I learned this by doing the spring experiment, the Laura and Kathy experiment, and dropping two thing while standing on a counter.

It is important to know these things because if you do not know Newton's three laws then you will not understand how an object starts to move, how it keeps moving, and how other objects effect the way he moves.