Simple Pendulum

A simple pendulum is a weight suspended from a pivot in a way that it can swing freely. When a pendulum is displaced sideways from its resting or equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released the pendulum after displacing, the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also to a slight degree on the amplitude, the width of the pendulum's swing.
I am suggesting a video that i find very simple regarding explaining the features of a simple pendulum.
suggested video for simple pendulum in indian accent 
 I always intend to suggest short timed videos with simple explanations of the phenomenon. I am suggesting another video to learn some specific terminology as well as working principle of a simple pendulum.
suggested video

re-view of the screw gauge

hi
its a video that i already have shared on my blog earlier. however I am posting the link again for the students of 9th C. you can watch the video to revise the method of determining the reading using a micro meter screw gauge.
click here to see the video selected to show the method to determine the reading

I hope you will find the video helpful
regards
kashif jamal

effective content for electromagnetic spectrum

hi
 I want to share a very effective and focused website with all my readers. It has very relevant content that I found very helpful for developing basic understanding. The link for the website is given below:
 Mini Physics
 further more you can search topic wise as I suggested the webpage to my students of X-Cambridge for exploring uses of electromagnetic waves and for that another link in given below that will directly open the required page:
electromagnetic waves and application
hope you will like the search and will find the content interesting and helpful.

yours truely
Kashif Jamal

click link for screw guage

Screw gauge principle and description 

micro metre screw gauge for 9-C

Its an effective and detailed video from the youtube.com
https://www.youtube.com/watch?v=11EM0nZUdqE

The URL is given above, click it to see the video.

Screw Gauge: (history)

The word micrometer is a neoclassical coinage from Greek micros, meaning "small", and metron, meaning "measure". The Merriam-Webster Collegiate Dictionary says that English got it from French and that its first known appearance in English writing was in 1670. Neither the metre nor the micrometre (μm) nor the micrometer (device) as we know them today existed at that time. However, the people of that time did have much need for, and interest in, the ability to measure small things and small differences. The word was no doubt coined in reference to this endeavor, even if it did not refer specifically to its present-day senses.
The first ever micrometric screw was invented by William Gascoigne in the 17th century, as an enhancement of the vernier; it was used in a telescope to measure angular distances between stars and the relative sizes of celestial objects.
Henry Maudslay built a bench micrometer in the early 19th century that was jocularly nicknamed "the Lord Chancellor" among his staff because it was the final judge on measurement accuracy and precision in the firm's work. In 1844 details of Whitworth's workshop micrometer were published. This was described as having a strong frame of cast iron, the opposite ends of which were two highly finished steel cylinders, which traversed longitudinally by action of screws. The ends of the cylinders where they met was of hemispherical shape. One screw was fitted with a wheel graduated to measure to the ten thousandth of an inch. His object was to furnish ordinary mechanics with an instrument which, while it afforded very accurate indications, was yet not very liable to be deranged by the rough handling of the workshop.
Thanks for your time

                                                                                                              Yours Truly
                                                                                                              Kashif Jamal
 

up coming topic for 10-C

sound and its properties

refraction in waves according to the wavefront...

direction of wave motion is perpendicular to the wavefront

dont get mixed up with wavefront and direction of a wave :)