10/5 Chao

MY THOUGHTS AT THE BEGINNING OF CLASS

            Thank goodness the board said “Check p. 54 #37 – 46” because I surely did not understand some questions. Oh, and we get our 2.4-2.5 guided readings back…and our Kinematics tests. Oh, don’t forget to turn in the pair check from yesterday. Wait, I already did that. Did I? Clearly I need sleep.

WHAT REALLY GOES ON IN CLASS PART 1

            Those two aforementioned papers will be waiting for any reader who was absent today in his or her folder, waiting to meet the hungry eyes. Using our handy dandy keys that Coats-Haan passed out to us and our partners, we checked over our homework from the previous night. While doing that, Coats-Haan passed around calculators with the QUADFORM program on them. Sonny helped our table link our calculators with this shortcut way to enter numbers for the quadratic formula.

            The notorious number 44 was a common question that left some of us befuddled. With her handy-dandy SmartBoard, Coats-Haan explained that when an object is thrown up in the air from some initial height and with some initial velocity, the endpoints of the objects’ journey are the endpoints that truly matter because at that certain height, whether the object is traveling up or down, the velocity will be the same and to find the end velocity, use V_f = V_i + at. A in this case will be -9.8 m/s², the acceleration constant for Earth’s gravity.

           As usual, Coats-Haan had a lot planned for us to do today so we didn’t get through everyone’s questions. If you, reader, would like to go ask Coats-Haan to explain some questions to you that you had trouble on or just to visit her with some stolen flowers, that is perfectly OK to happen between 6:30 to 7:30. She’ll be waiting.

            After the usual homework checking and Patricia and Sonny’s usual conversations about general “senior” things, Coats-Haan showed us a YouTube video. While it was loading, Coats-Haan let out all of the frustration she has about Lakota technology. Many of us would agree, even you, reader, perhaps, that Lakota technology just, well, isn’t the best. After a few long moments, Coats-Haan showed us a 1970’s experiment done by astronauts during the Apollo missions. Now of course, the video quality was slightly not up to par, considering that cell phones these days have “a thousand times more memory” than the cameras and computers used to power the Eagle, according to Coats-Haan. The video showed an astronaut holding in his hands a hammer in one and a feather in the other. Coats-Haan told us that because of air resistance and our atmosphere, Galileo’s postulate does not seem to be true regarding two different falling objects. If the hammer and the feather were dropped in our classroom, the hammer would meet the ground first. However, this astronaut daringly and gingerly let go of the two items and well, Galileo’s right after all. They both land at the same exact time onto the moon’s dust-laden ground. It’s hard to tell from the fuzzy, pixilated footage but yes, the feather lands right beside the hammer from the same height.

            Next, we moved on to a different topic known as linear regression, which leads me to the question of the day.

QUESTION OF THE DAY

Coats-Haan (a.k.a. ch) asked, “What is the point of linear regression?”

My answer: The point of linear regression is to minimize the amount of displacement of a point plotted on a graph based on data and the distance of the X and Y coordinates from the true line of best fit. In other words, we use linear regression to find the best line of best fit that would most accurately represent the data that we obtained, since there can be so many lines of best fit drawn through a set of data. For linear regression, the r value when inputted into a calculator is ideally 1 because then the linear regression is a perfect line.

MY THOUGHTS AGAIN

            What’s a derivative and she’s taking the derivative of what? Oh, she told us to not worry. This is calculus related.

WHAT REALLY GOES ON IN CLASS PART 2

            There’s one rule of simple logic in physics we will never break when it comes to graphs: we never connect the dots. Period.

            Coats-Haan pulls up a TI-84 calculator program and we can see what she’s doing as well as her key history. She shows us that we can use some data and the calculator will help us calculate linear regression. First we press STAT, choose option 1: Edit, then enter our X values in the L1 column and our Y values in the L2 column. This table will help us determine the linear regression. It serves as our list and if you want to clear an entire column, you simply select a value of that column, go up until L1 or L2 is selected and press CLEAR. After our list is complete, we select STAT again, this time switching to the CALC menu in which we select option 4: LinReg (ax + b). Pressing ENTER will reveal a menu like this

            LinReg
            y = ax + b
            a = …
            b = …
            r² = …
            r = …

            If the r² and the r values do not show up, select 2nd 0 to select CATALOG, then go the D options and select DiagnosticOn. Ideally, r should equal 1.

            This material will be on the test and we will have to know how to do it or else it is a “fail” (her words, not mine). Expect this material on the test next Thursday the 13^th.

            Then, Coats-Haan asked each group to grab a golf ball, p. 39 of our lab manual, and a timer. We stole quickly and quietly through Main Street to go to the stadium (Patricia and Sonny still jabbering away about their “senior” things). The “most coordinated” person stood at the top of the visitors’ bleachers to drop the golf ball. The “second most coordinated” person stood at the bottom along with the rest of the group timing and tossed the golf ball up to the “most coordinated person” (all her words, not mine). Miranda is obviously the most coordinated person as declared by Coats-Haan. My table sent Jasmine up, since my coordination clearly renders me unable to catch something (have you tried throwing me a football?) and she indirectly volunteered.

            Since we only had 15 minutes, we did three trials in which we timed each one and then we headed back. It was nice outside except the grass was extremely dewy and half of the bare patches were covered with mud. Our golf balls looked more brown than white by the time we finished timing our trials.

            That about wraps up what happened but before I forget, there’s something that has to happen AFTER class right?

HOMEWORK

            We received a linear regression practice worksheet in which we use the calculator to figure out the line of best fit (linear regression) for two sets of data and graph them on the back. We also have to complete a report (on notebook paper or the back of the lab manual page).