We added the last descriptor of motion - acceleration - for C and F Blocks today. Keep in mind that acceleration is not just a change of velocity, it is the rate of velocity change and can involve both the speed of the motion and the direction. And be very mindful of the meaning of signs when evaluating accelerated motion. Acceleration and velocity can have the same sign, which means the speed increases, or opposite signs that indicate the speed decreases. We went over the situations where you have zero velocity but do have acceleration (like a ball at the top of it's rise) or where you have velocity but zero acceleration (object continues to move at constant velocity). We'll go over your homework problems tomorrow and then put all these descriptors together into what are called the kinematics formulas, which are powerful tools for analyzing the motion of objects.
F Block reached kinematics land today and, after an overview of the topic and relevant formulas, were given time for practice. It is easy to trip up with these - you get signs wrong, overlook implicit information, etc. - and, since we'll use them heavily, getting started on the right foot is important. We'll review these tomorrow before launching into a discussion of free fall and how to apply the kinematics formulas to objects in free fall.
B Block got to play with basketballs today to analyze their motion as they were tossed into the air. Position/time, velocity/time and acceleration/time graphs were generated and folks were able to put what we've been talking about in lecture to practice analyzing these graphs. It was to be expected that the position/time graph was curved because the motion had acceleration. It was to be expected that the velocity/time graph was linear because the acceleration was constant. That was reinforced by the acceleration/time graph, since it was basically a straight horizontal like right around -10 m/s2 (accepted value for acceleration due to gravity, on average, is -9.81 m/s2). Tomorrow, we'll discuss the lab and then head into our discussion of kinematics.
9/8/11
9/7/11
Not a Happy Rain
Wow, is today dreary... luckily, we're studying motion which is FUN FUN FUN!!!
Ok, enough of that. B and E Blocks entered into a discussion of accelerated motion. Acceleration, the rate of change of velocity, can occur either through a change of speed or direction. We'll concentrate on the speed change for now, but remember the direction piece when we hit circular motion. We took time to look at acceleration conceptually, graphically and with equations and began to creep into a full kinematics discussion that we'll hit tomorrow for E Block and on Friday for B Block. Tomorrow, for B Block, is a lab that will let you examine the position-time and velocity-time graphs we've discussed and you will use them to interpret the motion of a ball in free fall - our next topic of study.
C Block conducted their Ball Toss lab and got very good results. The software provides position-time, velocity-time and acceleration-time graphs for a single piece of motion, so the movement of the ball through the air could be visualized and analyzed in a variety of ways. Consider the shape of each graph and make sure you explain them in your lab conclusions. Why do I expect the velocity/time graph to be nicely linear, for example... we'll go over the lab tomorrow before diving into a deeper study of acceleration. We'll hit the special circumstance of acceleration due to gravity a little later in the chapter.
F Block began their discussion of motion with an introduction to frame of reference and a few basic descriptors of motion. We took special care to distinguish the vector quantities (displacement and velocity) from the scalar ones (distance and speed) and make sure that, for tonight's homework, you include direction with your answers if the value is a vector. Tomorrow, we'll add another descriptor of motion - acceleration and then use all three on Friday to examine how we can use math to describe and make predictions about motion through the use of the kinematics formulas.
Maybe it will have stopped raining by then...
Ok, enough of that. B and E Blocks entered into a discussion of accelerated motion. Acceleration, the rate of change of velocity, can occur either through a change of speed or direction. We'll concentrate on the speed change for now, but remember the direction piece when we hit circular motion. We took time to look at acceleration conceptually, graphically and with equations and began to creep into a full kinematics discussion that we'll hit tomorrow for E Block and on Friday for B Block. Tomorrow, for B Block, is a lab that will let you examine the position-time and velocity-time graphs we've discussed and you will use them to interpret the motion of a ball in free fall - our next topic of study.
C Block conducted their Ball Toss lab and got very good results. The software provides position-time, velocity-time and acceleration-time graphs for a single piece of motion, so the movement of the ball through the air could be visualized and analyzed in a variety of ways. Consider the shape of each graph and make sure you explain them in your lab conclusions. Why do I expect the velocity/time graph to be nicely linear, for example... we'll go over the lab tomorrow before diving into a deeper study of acceleration. We'll hit the special circumstance of acceleration due to gravity a little later in the chapter.
F Block began their discussion of motion with an introduction to frame of reference and a few basic descriptors of motion. We took special care to distinguish the vector quantities (displacement and velocity) from the scalar ones (distance and speed) and make sure that, for tonight's homework, you include direction with your answers if the value is a vector. Tomorrow, we'll add another descriptor of motion - acceleration and then use all three on Friday to examine how we can use math to describe and make predictions about motion through the use of the kinematics formulas.
Maybe it will have stopped raining by then...
9/6/11
Motion!
B, C and E Blocks began their study of motion today with an overview of distance/displacement and speed/velocity. We will dig into the difference between scalar and vector quantities in more detail in the next chapter, but hopefully everyone got the basic idea that vectors require a statement of direction, whereas scalars only report magnitude. We also looked at the importance of a frame of reference for evaluating motion and started quantifying motion changes graphically and with the velocity formula. Tomorrow, C Block will conduct a lab investigation that will take a very graphical approach to the study of motion, using a motion detector to track a ball tossed into the air. B and E Blocks will move on to a discussion of acceleration and the major kinematics formulas.
F Block reviewed last week's material on the scientific method and metric system, then launched into the area of accuracy/precision. Accuracy problems are usually our fault somehow, but precision limitations stem from the physical design of the measuring tool. To correctly report the precision of a measurement, rely on significant figures. This is especially important with using several measurements in a calculation. In the case of ambiguous trailing zeroes, fall back on scientific notation. Truthfully, it's more efficient to report all values that way since it can make estimated calculations easier, but SI prefixes work well, also. Tomorrow - we begin our study of motion!
...and yes, this image is relevant to motion, so don't mock me...
F Block reviewed last week's material on the scientific method and metric system, then launched into the area of accuracy/precision. Accuracy problems are usually our fault somehow, but precision limitations stem from the physical design of the measuring tool. To correctly report the precision of a measurement, rely on significant figures. This is especially important with using several measurements in a calculation. In the case of ambiguous trailing zeroes, fall back on scientific notation. Truthfully, it's more efficient to report all values that way since it can make estimated calculations easier, but SI prefixes work well, also. Tomorrow - we begin our study of motion!
...and yes, this image is relevant to motion, so don't mock me...
9/5/11
Happy Birthday Freddie!
Freddie Mercury, lead singer of Queen would have been 65 today. The man had a 4-octave range (if you don't know why that's impressive, ask Mrs. Laflamme) and really entertained his audience in an age when Auto-Tuning and lip-synching were unheard of. The guys who do the Google doodles crafted a tribute and it's a hoot... BTW - did you know that Queen's guitarist, Brian May, has a Ph.D in Astrophysics...
9/4/11
9/1/11
And, We're Done
Short week due to the impending holiday, and what's better for a short week than a nice fire drill. C Block lost some time due to that, but we made it work. B and C blocks spent time discussing the concepts of accuracy and precision and why precision (though we sometimes don't give it it's fair due) is a vital part of reporting measurements. Through the use of significant figures and scientific notation, the precision of values can be made clear to everyone reading them, which is critical for science, medicine, engineering... On Tuesday, we start in on one-dimensional motion!
E Block had their lab period and conducted an introductory investigation to familiarize themselves with the Vernier probeware system. Between the sensors/probes and the data analysis features, this system allows for highly quantitative labs to be performed, which is the name of the game in physics. Also, the various sensors make possible a good number of measurements that more classical apparatus do not easily permit. We'll go over the lab on Tuesday and then hightail it into our study of kinematics. Remember to have both yesterday's assignment and the lab write-up ready to go on Tuesday.
F Block reviewed yesterday's lab and began a discussion of the metric system, dimensional analysis and the scope of physics. We'll round out Chapter 1 on Tuesday and find ourselves in our study of motion on Wednesday. Just a head's up - looking over the lab sheets, I noticed a lot of people didn't follow the proper procedure for writing the lab synopsis. I don't care if you do it in paragraph form or in a list, but ALL components should be there. Since this is the first one, I gave the people who did it correctly an extra point and those who did not still got full credit. Next time, though, expect a reduction in grade.
E Block had their lab period and conducted an introductory investigation to familiarize themselves with the Vernier probeware system. Between the sensors/probes and the data analysis features, this system allows for highly quantitative labs to be performed, which is the name of the game in physics. Also, the various sensors make possible a good number of measurements that more classical apparatus do not easily permit. We'll go over the lab on Tuesday and then hightail it into our study of kinematics. Remember to have both yesterday's assignment and the lab write-up ready to go on Tuesday.
F Block reviewed yesterday's lab and began a discussion of the metric system, dimensional analysis and the scope of physics. We'll round out Chapter 1 on Tuesday and find ourselves in our study of motion on Wednesday. Just a head's up - looking over the lab sheets, I noticed a lot of people didn't follow the proper procedure for writing the lab synopsis. I don't care if you do it in paragraph form or in a list, but ALL components should be there. Since this is the first one, I gave the people who did it correctly an extra point and those who did not still got full credit. Next time, though, expect a reduction in grade.
8/31/11
For Real, This Time
Yesterday was housekeeping, today was real work. B, C and E Blocks reviewed the scientific method and the basics of the metric system and checked the homework problems for metric conversions. As I said in class, the method you choose to perform unit conversions is up to you, as long as you do it correctly. You will find yourself often having to convert units (metric mostly, but some non-SI units, as well), so hammer that skill down now. Time was also taken to discuss the importance of models in physics and why their use is critical for analyzing complex systems. We will often make assumptions about a system that reduce it to a model and, surprisingly, still get respectable predictions of real-world events. Tomorrow (Tuesday for E Block), we tackle accuracy and precision, the use of scientific notation and significant figures and the value of checking answers for dimensional consistency.
F Block conducted an introductory lab investigation to get them used to working with the Vernier probeware system. Equal increments of pennies were weighed and graphed to explore how Vernier presents real-time data and how the program performs mathematical data analysis. We modified the experiment a little by having groups test both pre-1982 pennies and post-1982 pennies and comparing the weights. Remember to follow the instructions for writing a lab synopsis and answer all questions/perform all calculations required in the lab handout. E Block will perform this lab tomorrow and F Block will take up today's lecture material in class.
F Block conducted an introductory lab investigation to get them used to working with the Vernier probeware system. Equal increments of pennies were weighed and graphed to explore how Vernier presents real-time data and how the program performs mathematical data analysis. We modified the experiment a little by having groups test both pre-1982 pennies and post-1982 pennies and comparing the weights. Remember to follow the instructions for writing a lab synopsis and answer all questions/perform all calculations required in the lab handout. E Block will perform this lab tomorrow and F Block will take up today's lecture material in class.
8/28/11
11-12 is On!
Starting the new year is always a bother for both teachers and students, but hey... can't do anything about it so buck up and just get it done. This week is very short, but that doesn't mean we're going to be slacking. We'll be attacking Chapter 1, which introduces folks to the identity of physics and some of the fundamental skills you'll need throughout the year. Take time this week and weekend to make sure you have a good calculator to use - you WILL need it and the faster you get used to using it, the happier you will be. As for lab, we'll be working through an activity that will allow people to learn the Vernier system and get a feel for how the lab program will be conducted this year. And weigh pennies... Come on, you know playing with pennies is fun. Just admit it.
After this introductory chapter, we'll be moving directly into a study of motion. Distance/displacement, speed/velocity and acceleration are going to be the big players and there will be a set of formulas that you'll have to tackle to analyze the motion of objects. Get familiar with them - they are going to be your buddies for a good long, LONG, time in the course.
After this introductory chapter, we'll be moving directly into a study of motion. Distance/displacement, speed/velocity and acceleration are going to be the big players and there will be a set of formulas that you'll have to tackle to analyze the motion of objects. Get familiar with them - they are going to be your buddies for a good long, LONG, time in the course.
12/6/10
Torquin' Through Monday
Honors Physics completed their discussion of simple machines. We reviewed the types of simple machines, described how they functioned to make work easier and the two formulas for mechanical advantage. Added in the concept of efficiency emphasized the connection between the action of many of the simple machines and the concepts we've been covering in the rotational motion unit. Tomorrow, a lab that takes us back to centripetal force and tangential velocity. Wednesday, review and Thursday will be exam day.
Physics B conducted a lab investigation on rotational equilibrium. Setting up balanced torques for a variety of masses demonstrated clearly that force (weight) was not the only player in the game. Lever arm is critically important and rotational equilibrium is dependent not on balanced forces but on balanced torques. Tomorrow, we'll discuss the lab in more detail before continuing on with our discussion of rotational inertia and angular momentum.
Physics F spent time with rotational inertia and applied that idea to rolling. How easily an object rotates or rolls depends on its moment of inertia, and that depends on the object's mass and the distribution of that mass around the rotational axis. For single objects, there are often several axes around rotation can occur, but it is easier for some than for others. We looked at some moment of inertia formulas for simple shapes and it became clear why for a hoop and a ball, with identical masses and radii, the ball would always win a race when propelled by the same force - smaller moment of inertia = easier rotation.
Physical Science took time to discuss laboratory write ups. There's been problems in that area, so with the lab we just completed as a guinea pig, we looked at what each section of the lab write up should contain and what needed to be done to the current labs to bring them up to code. Work on your rewrites tonight and let's see how things look tomorrow.
Homework
Honors Physics: 8.4 Section Review and p. 308 #39 - 43
Physics B: None
Physics F: p.165, 166 in packet #7-13 and 27-30
Physical Science: Rewrite lab write ups for simple machines labs
Physics B conducted a lab investigation on rotational equilibrium. Setting up balanced torques for a variety of masses demonstrated clearly that force (weight) was not the only player in the game. Lever arm is critically important and rotational equilibrium is dependent not on balanced forces but on balanced torques. Tomorrow, we'll discuss the lab in more detail before continuing on with our discussion of rotational inertia and angular momentum.
Physics F spent time with rotational inertia and applied that idea to rolling. How easily an object rotates or rolls depends on its moment of inertia, and that depends on the object's mass and the distribution of that mass around the rotational axis. For single objects, there are often several axes around rotation can occur, but it is easier for some than for others. We looked at some moment of inertia formulas for simple shapes and it became clear why for a hoop and a ball, with identical masses and radii, the ball would always win a race when propelled by the same force - smaller moment of inertia = easier rotation.
Physical Science took time to discuss laboratory write ups. There's been problems in that area, so with the lab we just completed as a guinea pig, we looked at what each section of the lab write up should contain and what needed to be done to the current labs to bring them up to code. Work on your rewrites tonight and let's see how things look tomorrow.
Homework
Honors Physics: 8.4 Section Review and p. 308 #39 - 43
Physics B: None
Physics F: p.165, 166 in packet #7-13 and 27-30
Physical Science: Rewrite lab write ups for simple machines labs
12/3/10
They See Me Rollin'
They calculate my moment of inertia...
Honors Physics went over their work on angular momentum and angular kinetic energy before moving on to simple machines. In grade 9, we lumped simple machines in with the work and energy chapter and that's fine. Both arenas, rotational motion and work are good ways to evaluate machines. We defined machines and began to look at how they functioned to make work easier. Actual and ideal mechanical advantage were contrasted and we will pick up with the families of machines and efficiency on Monday.
Physics B and F went over their torque work before beginning a discussion of rotational inertia. Objects do resist changes in rotation, but mass is not the only player. The distribution of mass is also important. Clustering mass around the rotational axis produces a lower rotational inertia than placing the mass at a distance from the axis. We'll build on this next week. On Monday, B's long block, look forward to a lab dealing with rotational equilibrium.
Physical Science got time in class to work on test corrections. Students can earn up to a maximum of 1/3 the points they missed back on their score. Next week, talking about lab write ups and continuing on with work and power.
Homework
Honors Physics, Physics B and F: None
Physical Science: Complete test corrections (if you get completely stuck on one, remember to ask me in class on Monday)
Honors Physics went over their work on angular momentum and angular kinetic energy before moving on to simple machines. In grade 9, we lumped simple machines in with the work and energy chapter and that's fine. Both arenas, rotational motion and work are good ways to evaluate machines. We defined machines and began to look at how they functioned to make work easier. Actual and ideal mechanical advantage were contrasted and we will pick up with the families of machines and efficiency on Monday.
Physics B and F went over their torque work before beginning a discussion of rotational inertia. Objects do resist changes in rotation, but mass is not the only player. The distribution of mass is also important. Clustering mass around the rotational axis produces a lower rotational inertia than placing the mass at a distance from the axis. We'll build on this next week. On Monday, B's long block, look forward to a lab dealing with rotational equilibrium.
Physical Science got time in class to work on test corrections. Students can earn up to a maximum of 1/3 the points they missed back on their score. Next week, talking about lab write ups and continuing on with work and power.
Homework
Honors Physics, Physics B and F: None
Physical Science: Complete test corrections (if you get completely stuck on one, remember to ask me in class on Monday)
12/2/10
Circular Motion Continues
Honors Physics took time to review and refresh their problem solving skills for rotational equilibrim before moving on to other properties of rotational motion - angular momentum, Newton's 2nd law applied to rotational motion and rotational kinetic energy. The concepts are familiar, they are now simply applied to rotating bodies. For problem solving, here's a hint (especially for conservation of energy problems): ω = vt/r...
Physics B and F reviewed their torque homework and spent time working with the idea of rotational equilibrium. The problem set for homework will make you think, so here's your hint: Sometimes you need to look at both conditions for equilibrium to be able to solve a problem.
Physical Science completed their simple machines lab. Little problem following directions for the lever piece, but everyone finally pulled together a good set of data. Get the writeups completed (along with your examples of the three classes of levers) for tomorrow so that we can use the information to illustrate our discussion of work and power.
Homework
Honors Physics: 8C #1, 2; 8D #1, 3; 8E #1, 2
Physics B: Torque practice problems packet
Physics F: Ancillary packet p. 165-166 #1-4, 21-23 and Torque practice problems packet
Physical Science: Complete lab write up
Physics B and F reviewed their torque homework and spent time working with the idea of rotational equilibrium. The problem set for homework will make you think, so here's your hint: Sometimes you need to look at both conditions for equilibrium to be able to solve a problem.
Physical Science completed their simple machines lab. Little problem following directions for the lever piece, but everyone finally pulled together a good set of data. Get the writeups completed (along with your examples of the three classes of levers) for tomorrow so that we can use the information to illustrate our discussion of work and power.
Homework
Honors Physics: 8C #1, 2; 8D #1, 3; 8E #1, 2
Physics B: Torque practice problems packet
Physics F: Ancillary packet p. 165-166 #1-4, 21-23 and Torque practice problems packet
Physical Science: Complete lab write up
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