Projectile Motion

The projectile motion concept is one of the more difficult concepts for students to comprehend. Also, it is also one of the more difficult concepts to teach. The teacher who teaches projectile need to learn the following ideas about this motion and its equations before tackling it otherwise the teacher falls into the trap of thinking that some equations involving it has "no solution,"

1. Equations for projectile motion are idealized setup and maybe difficult to perform and even verify in an outside set-up with a high degree of precision and accuracy.
2. To make the experiment less erroneous otherwise it might develop misconceptions to students is that the projectile in the projectile motion is also idealized (Actually a point-mass). The closest thing to a point mass in this experiment are the following - a marble, a metal ball or a small piece of stone. 
3. A plane or winged projectile follows a path not described by the kinematical equations. More so a rocket. A rocket loses mass as it it propelled and therefore does not follow a path described by the kinematical equations.  The more aerodynamically sound the device is, the less it follows the kinematical equations. Aerodynamical system is affected by air pressure. 
1. For example, a pingpong ball approximately follows the kinematical equations. However when a player applies strong SPIN to the ball, the ball either bounces higher or lower. In flight the ball curves its path either to the right, left, or drops fast or drops slower than usual,. The spin gave it aerodynamical effects.
2. The same idea works for BADMINTON bird. The :"ball" drops fast since the ball is dragged by the air so as it reaches its peak it drops almost vertically
4. The solutions for kinematical .equations sometimes need trigonometric identityes and property

The complete K+12 Competencies

https://docs.google.com/file/d/0B52LsZdeqWiFRGhEWFl2aTBzV0k/edit?usp=sharing
https://docs.google.com/file/d/0B52LsZdeqWiFSW1CMTBQVzk1Zkk/edit?usp=sharing

Spend time reading and understanding these links. Download them if you must.

Ever wondered how Tony Starks created his new element in IRON MAN 2?

Watching Iron Man 2 and seeing Tony Starks create a new element from his home laboratory is probably a great fiction to everyone. In the movie, Thor the scientist told Thor's future girlfriend Jane that it is fairy tale, Jane answered back "a precursor to science fact." I was bemused by the idea that THor said to Jane later that "In our world, what you consider as magic, is science to us."

I suppose that the writers of these science fantasy stories were reading science fiction or SF stories. Because a number of times, a science fiction invents an idea, science seem to follow suit.

Take for example, this article
http://phys.org/news/2013-06-particle-tabletop-chapter-science.html 

After reading it is now easier to imagine what Tony Starks did in Iron Man 2. Although he did invent an ultra heavy highly radiating metal, the concept is not anymore out of reach.

http://phys.org/news/2013-06-particle-tabletop-chapter-science.html

The last of the PSSLC's of 2003.

Next school year 2014-2015, we'll be witnessing the last batch of RBEC students graduating from the old Curriculum. The curriculas before it, as far as my memory can carry me were SEDP, NSEC, RBEC, BEC as well as SEC and the latest was ASEC. Now its K+12. The last two batches were warned that failing in this two year period would result to spiraling down to the K+12 and would entail additional years just to reach college. Then again, the students said if they enter Grades 11 and 12, they can already find jobs after it and are not in a hurry to enter college years. One can always outreason what others state as warnings (or heralds-depending on who is listening). 

The last batch of Physics curriculum had remained the same since it was introduced last 2003. The PSSLCs of the past 10 years, was itself an experimental set of LCs. If one were to study the Modules created for K+12 and the Prototype Lesson Plans of the 2003 PSSLCs, one can actually feel the the K+12 modules were "rehashed" versions of the 2003 Prototype Lessons. The Prototype Lesson Plans themselves show hallmarks of an amateur mind, with lots of ENCARTA, scanned comics and copied but uncited books that were more done haphazardly than products of longer research or studies. What does that tell me of the K+12? It feels like more of the same.

Why did I say that the 2003 PSSLC's were experimental? The lesson topics covered the REVERSED (Optics to Mechanics) topics of standard Physics textbook treatment (Mechanics to Optics). There was never an explanation as to why the reversal was done. It never served its purpose since College entrance tests always follow the Physics standard treatment of topics. When it was first shoved down to us, all Physics major teachers were in an uproar until we were told to Tow the line. Of course we never towed the line and opted to follow how college treat Physics since that would be the Physics that our students will eventually face.

THIS IS THE "DYING" PSSLCs of PHYSICS

https://docs.google.com/file/d/0B52LsZdeqWiFSWZiVDR3Y3R6Y28/edit?usp=sharing

Happy to share this to all of you.

K+12 PHYSICS FOR HIGH SCHOOL

The Physics Curriculum of K+12

The K+12 for high school (Grades 7 to 10) is spread-out over four years of high school and taken by piecemeal. Based on my understanding of the K+12 curriculum, the idea was to train high school teachers for teaching the K+12 Physics and by Grade 10, it will be spiraled. The teachers then will teach all year levels but by quarters, depending on the schedule. But the way some administrators and their consultants have understood the K+12, they only send First year teachers (usually GenSci Majors) where they learn all 4 subjects -Chemistry, Biology, Physics and Earth Sciences in one week seminars. According to feedbacks, some of these teachers didn't teach the subjects at all (Physics especially).. This could lead to a serious implication that by fourth year (Grade 10) the students will have to deal Physics according to actual Physics major teachers at Grade 10 and will be discussing higher levels of Physics where the students arriving at their Grade 10 levels don't know Physics at all. 

Luckily I got copies of the hand-outs and DepEd and managed to collect all the Physics LC.s and objectives into one Physics "curriculum." 

The K+12 Physics Objectives and LCs 

The collected LC's can assist all Pinoy Physics teachers waiting (or already undergoing) training for K+12. Any changes before Grade 10 arrives can be freely done because its a spreadsheet. This can easily tell a Physics Teacher how to construct their Lessons.

I hope this can help. Enjoy downloading.

The First Law of Motion - Newton's First Law of Motion


A typical answer to this one is "An object at rest or in constant motion tends to remain in that state unless an outside force acts to change such state". 
Simple and easy to recall but the generalized statement reduces the concept associated with such a statement. When I lecture about this Law, the divide it into two with the second statement further subdivided to two.

Newton's First Law of Motion

1. An object at rest tends to remain at rest unless a net force acts to make it move.

• An object in constant velocity will remain in such state of motion unless a net force acts to change that constant velocity.
• An object in constant angular velocity will remain in such state unless a net torque acts to change the constant angular velocity.

Work, Work, Work

One of the things that a teacher encounter in a classroom are the misconceptions developed and even reinforced over the years. As 4th year teacher, I need to let them change their vehemently held ideas. One of them is the concept of Work. Defined by a student when called to recall it from their elementary and early high school, they recite this mantra: Work is  Force times distance of W=Fd . FALSE of course for several reasons.

1. Work is a scalar quantity, so it cannot be a product of a vector (Force) and scalar (distance). The result of such multiplication is a vector quantity. 
2. The multiplication used is a dot multiplication not algebraic multiplication and so must be expressed as Work = F•d.
3. The other factor is NOT distance but displacement. The dot product of displacement (Vector) and force (Vector) is Work (Scalar).

The usual equation given in books is W = Fdcosθ. This equation is the magnitude version of the above mentioned vector equation. The θ is the angle between the Force F and the displacement d and the usual angle between the two is 0º and the value of cosine zero (cos0º) is 1. The entire equation then simplifies to W = Fd, which is the magnitude version.


Furthermore, it is not always TRUE that when force causes motion, work is done. When Force causes motion that is perpendicular to its action [Cosine(90º)= 0], no work is also done. But that is the only instance it can happen. 


To some teachers also include the fact that Work is also the product of torque and angular displacement. W = Γθ. Here when a force acts on a body pivoted at a certain point, it spins and does not translate or change its position.