What's the difference between "Higher Level" and "Extension"?

[Ilkana]

Hi everyone

Probably irrelevant, but I'm a bit confused.

I'm doing HL Biology and HL Chemistry, and today when I was reviewing Topic 2 and Topic 12 (SL and HL of Atomic Theory, respectively), in my text book I came across "Higher Level" and "Extension".

I'm in my last year of IB, and last year my chem teacher taught the HL Atomic Theory stuff to us cause it's pretty easy, but we only learnt "12.1.3-12.1.5" and I was searching for 12.1.1 and 12.1.2 and they're under "Extension".

What is this?

There's "Extension" for all the topics! Even the HL topics that we've covered and finished in class...there's "Extension" stuff that I haven't learnt! Is this not "AHL"? Why is it there?

It's freaking me out. Do I need to know it?

Thanks for your time guys!

[dessskris]

What textbook do you use? IBID?

Extension is literally extension, it's an addition to the IB syllabus.

Therefore it's something you don't have to learn

You may want to learn it just for the sake of broadening your knowledge, that's it.

[Ilkana]

The textbook I use for Chemistry, at least, has been written by IB examiners and thus tailored to the IB syllabus...

but okay, cool ! Hahaha, nah, I love extra knowledge and all that but.. HL Chemistry and HL Biology... I have enough interesting knowledge to learn

Thanks!!