Re: weak and loud bones?
At your young age, you need to see your family doctor. Most times, when someone "cracks" their knuckles, it is the sound of bubbles in the joint fluid that makes that sound and it is completely harmless. Same for the other joints. I know my son used to "crack" his neck all the time and he is just fine.
But just in case, since there are things that can go wrong with kids, you should show you doctor all the joints you can crack an ask if this is just harmless joint noises.
Most joint noises are just "noises". If those same joints hurt, a lot, then I'd be worried. But you said nothing about pain. Arthritis hurts....a lot. And in kids, you would see redness and feel heat around the joints too. Kids don't get osteoarthritis...the arthritis of aging...but can get arthritis if a joint is injured or they can get a type of arthritis that makes them sick all over.
I suspect you just have joint noises from those joint fluid bubbles and that is normal and harmless. But ask you doc to put your mind at ease.