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Showing posts from May, 2017

Superposition of two waves with different amplitude

I initially thought that even with a different amplitude two waves will still form a standing wave if they have the same frequency and move in opposite directions. So I tested it using Mr Loo Wee Kang's simulation and it turned out I was wrong. The blue and green waves are the individual waves moving in opposite directions. The red is vector sum of the two waves. As observed from the video, the red wave is not a standing wave but propagates.

Simulation of a magnet moving at constant velocity through a solenoid

http://www.physics.usyd.edu.au/teach_res/mp/doc/em_emf.htm While looking at the simulation, follow the graph plotted as the magnet moves through the solenoid. Lenz's law agrees with the conservation of energy by resisting the change that causes it. Mechanical energy changes to electrical energy and in turn thermal energy due to the resistance of the wires. Current flows from low to high potential in this case. Remember it is EMF (electromotive force) we are looking at here so in the same way IN a cell/battery current flows from low to high potential. What if the magnet is not at constant velocity but falls from rest through the solenoid? Think about it before watching the video below. Induced emf due to magnet falling through solenoid using Addestation Datalogger

Magical storytelling - The rise and fall of Nikola Tesla

One of my all time favourite TED talks Nikola Tesla was isolated at his death. Would we consider his a success though with all his contributions to mankind?

Shock and Awe: The Story of Electricity - Jim Al-Khalili BBC Horizon

Jim Al-Khalili does such a great job presenting a chronological flow of events. From electrostatics, to current of electricity, to the link to electromagnetism. Great resource to look at how a CRO was used to record the voltage of the Torpedo Marmorata, as well as Galvani's frog leg experiments. Also there is some discussion about how Faraday discovered the first motor . Despite only receiving formal education till he was 12, Faraday had a great thirst for knowledge and discovery.

BBC Documentary - The Secrets of Quantum Physics

The topic that always mystifies the students (and teachers). Write up on the BBC website.

Science books to spur interest

The Disappearing Spoon A Beautiful Question: Finding Nature's Deep Design I Contain Multitudes: The Microbes Within Us and a Grander View of Life A Short History of Nearly Everything

The Link

So what is the reason for the detachment between school and work? Does school not prepare you for a life in the work force or your career? Even with a physics/science education which aims to help one be in awe of the wonders and patterns in nature? Is that the fault of the exam or grading system? Students today are so much more fortunate with all the resources. Resource from the internet, teachers compiling notes or even providing links to youtube videos, simulations. Some demos are even shown "live". Yet with such good fortune, students seem to be more and more detached. They are unable to correlate the question on the paper to what they see in the lab or even in their everyday lives. So it is not a matter of lack of resources but how can I as a teacher help them draw the parallels between the question printed on the paper to the simulation/animation/video/demo. That is what I hope to do in due time.