It cracked at the top while still in the pan and then I rushed to take it out of the pan ( you are supposed to wait and let it cool a lil right?) and part of the sides were cracked just like the top and rushing it made it worse.

what is a science of cake, why did it crack

I had that problem recently, but the oven was screwing up and cooking too hot. I don't really know the science, but I've only had it happen one time and it cracked 2 of the 8 cakes I had in the oven at the time.

It could have been overbaked, or your oven could have been too hot!
Overbeating batter can cause cakes to crack...
HTH!

i had it at 335 ( it was a box cake w/ additions and the box said 350 ) but I am just a renter and have a cheap apartment oven, would not surprise me if it was being wonky.

it was a cake that was also sticky from pineapple and coconut cream, so it was taking forever to cook and it came out sticky yet crumbly. I messed up the water/juice ratio so I threw some more flour in there and I think I added too much. It was kinda dry while also being sticky.. kinda odd (tasted good though).

maybe too much flour..

i think all the things you just said about your cake is your problem. probably adding more flour was the culprit.

I read a tip just recently regarding 'cracking cake tops' during the baking process.. it was suggested that you lay a piece of greaseproof paper over the top of the pan during cooking. The feedback suggested this worked a treat Hope this helps!