Recovering Disc Space MBA

So I have had my MBA for about 2 weeks and I am trying to look ahead to the future so I have sone a clean install already, etc... learning time machine, so in the future hopefully I'll know how to handle some issue's.

I started to download a large file and stopped it in the middle of the download as I noticed my SSD HD space go from the 80 GB to 13 GB. So I stopped the download and deleted the part that had downloaded but I could never get any of the HD space back. Ended up learning how to do a recovery from Time Machine. What exactly could have happened. How come I didn't get the space back by putting items in the trash and emptying it. I did restarts, shut downs, disk utility, and nothing would get the space back but a restore.

Putting this thing through the paces to learn about Mac OS again!

Thanks!

It was about 55 GB ( guess I should of said about 80-13 GB). I was messing around mostly and was never going to download the entire file. But I still don't get how come it wouldn't let me delete it and regain the space. Especially since it never got even close to actually downloading that amount!

Guess I still have a lot of learning to do about my MBA and OSX since making this my main computer. Haven't had a Mac since the early to mid nineties. Been wanting a MBA for some time, and a new operating system helped me with my decision. Kind of gave me an excuse to get the MBA I was going to get one anyway just made the process faster!