Ranking is the place you come in your year
e.g. you might come 5/120 in maths or 60/70 in english
and that is determined by your assessments that you have at school in year 12
Scaling happens after you get your overall marks in the hsc, and how much that mark contributes to your aggregate and ultimately your atar
E.g. You get a mark of 90 for chemistry, and scaling will determine how much that 90 will contribute to your atar
and because chemistry is a high scaling subject, it will contribute more to your atar than say if you get a 90 in society and culture