Is science extension good? How come a lot of people don't do it?
I did it for 2 terms, then dropped it for a reason I will outline below. The subject is of beneficial value if you intend on studying Science in university - particularly if your university course has a lot of research and experiments involved. SciX covers some scientific philosophy, in-depth scientific research techniques, and statistical analysis. Additionally, you complete a major independent research task for a topic of your choosing. All in all, a good preparatory course for uni Science.
In relation to why many people don't do it, the main reason is that SciX is not offered in many schools. Furthermore, SciX (even for 1 unit) is a very
demanding subject - you begin your independent research task almost instantly and the amount of research which has to go into the task can be quite overwhelming. When I initially did SciX, there were about 13 people in the class. When I dropped the subject, 10 people had already dropped before me - all for the same reason: extremely demanding.
One other reason which not many people talk about (though I had this conversation with my teacher at the time who brought it up) is the scaling outcomes - the chance of getting an E4 is rather small. In the 2022 candidature of 658 students, only 8.4% received an E4 in comparison to 70.51% which received an E3. (https://www.boardofstudies.nsw.edu.au/ebos/static/BDHSC_2022_12_15345.html
Just as a note to anyone who wants to consider doing this subject, I would not recommend doing this subject alongside another extension subject unless you can handle work pressure and can manage your time well.