Hi OP
My son's school scared the life out of me last term regarding science teaching for GCSE.
During the options process, the children were given opportunity to request double or triple. Students would only be allowed to take the triple if they hit level 6a or above in their Y9 exams...so far, so good. We were expecting three individual science GCSE exams (Biology, Physics and Chemistry) at the end of Y11.
Then the school got to see the GCSE syllabus (AQA exam board) for double and triple science and decided to completely change their approach.
Double Science is now called 'Additional Science' and contains elements of all three sciences but it counts for two GCSE's. Triple Science is called 'Further Additional Science' and again, contains elements of all three sciences but counts for three GCSE's.
My son's school is getting all Y10's to sit 'Science A' (the GCSE science foundation paper) at the end of Y10, then depending on how they do*, they will either complete 'Additional' or 'Further' in Y11.
Many parents thought that 'double science' meant their child would get Biology+Chemistry or Chemistry+Physics etc without the 'third' science at all; that isn't how it works. Children taking 'Additional Science' (the double) will still study Biology, Chemistry and Physics in separate lessons.
The children taking 'Further Additional Science' (the triple) will have more to learn in less time. *We've been told this paper is extremely challenging and will only be open to the students who get an A in the 'Science A' GCSE and who also excel in their Maths end of year exams.
It might be worth finding out if your son's school is using AQA as their exam board and if they have a similar approach?
Good luck 