## Optical Illusions from Polarisers

[P4 to S4 Science - Light & EM waves] As an aficionado for science since young, I often wonder where the intrigue for optical illusions one might have, arose from. The fact that they betray our intuition? The fact that they often require some deeper knowledge which, once understood, provides a deep, pleasing feeling within oneself that you've learned something unique? The video contains a particularly cool optical illusion, where a black disc is formed in the middle of the tu

## Proof for the Area of a Circle

[P6 Maths and beyond: Circles] This is something that's exclusively useful for Mathematics. Whenever you come across a formula in your textbook, you should have the right to ask the teacher how the formula is derived, where it comes from. For example, let's say you have a scalene triangle of sides 8, 9 and 13 (clearly not a right triangle). Without knowing the height from any base to the opposite vertices, how is one meant to find out the area of this triangle without the sta