Scratch questions

Hi All, i am pretty new around here. Glad to see Squeak is so active still.

 I have been looking at new Squeak apps like Sophie and Scratch.
pretty cool! makes me want to learn Smalltalk.  Out of curiosity I
have read some of the FAQs about how to deploy a Squeak application. i
understand about image files,  the VM, and the basics.

 I was wondering about Scratch in particular. It seems really nicely
done. i am impressed because it's so nice looking and it launches
really fast too.

1) How do they get it to launch so fast? It launches in <1 second on
my system. In comparison,  Squeak 3.9 takes like 15 seconds to launch.
Sophie takes about 6 seconds. Why the disparity between these 3
examples?

2) The Scratch user interface is attractive and responsive. Is that
Morphic, or MVC or some other UI toolkit?

Thanks,

Alex Rice