O-level English : There is no point in preserving the past. We should be looking to the future.

Sample Essay

http://mareingenii.t15.org/EngOlvl/There%20is%20no%20point%20in%20preserving%20the%20past%20We%20should%20be%20looking%20to%20the%20future.html

Polarized Light Microscopy

A student of mine tore apart his old digital dictionary that he was going to toss in the trash. We had a nice time discussing its construction and he gave me its LCD screen from which I tore off a polarizing film. I cut the film into discs and added them to the light path of my Olympus CHB microscope. One went under the eyepiece turret while the other under the condenser.

These are the results:
Citric Acid Crystals at 100 times magnification (Camera : LG Optimus Black)

Small Citric Acid Crystal at 400 times magnification  

A technical treatment of this is available here:
http://www.microscopyu.com/articles/polarized/polarizedintro.html