[S3 and above: Stiochiometry & Mole] Let's say you have a junior whom is currently struggling with Chemistry, specifically the mole questions given how it's confusing and somewhat like complicated Maths. How would you explain the concept of moles to such a junior? Whether they might be a junior from school, or a child of a relative / your spouse, it's not always easy to explain what moles are, especially when they're based off of a ratio. Good news is, British physicist and s

[P4 Science - J1 Chemistry: Heat & reaction between oxygen & ethanol] You often know heat as a dangerous form of energy. The reason kids are often not allowed in the kitchen without supervision, of course, is because they rely on their eyes too much. They're not careful enough to catch onto the fact that heat is an energy, so it's not always visible. As a result, a hot oven can't be distinguished just by looking inside the oven. Same deal with hot water - One usually has to h

[P6 Maths and beyond: Circles] The following question is a tricky question from 1982 that a lot of people got wrong. It's deceptive (and tempting) to use the large circle B as the point of reference when answering this question. Sure, the circumference of Circle A makes three rounds around Circle B, but that is in relation to the circumference of Circle B as opposed to position of Circle A. In Maths, we must be rigorous with the question and the answer. The question specifies