Conceptual stuff like that is tricky if you don't already know it. I've found that visual explanation works best for building an intuition. My approach for day

Conceptual stuff like that is tricky if you don't already know it. I've found that visual explanation works best for building an intuition. My approach for day / night type of questions: - a soccer ball - a toilet roll - the lamp in your phone When you shine your lamp through the toilet roll on the ball, you get a neat 'terminator'.