Straighten a Bob

Straighten a bob with a flat iron
Q: What is easier to straighten yourself at home with a blow dryer or a flat iron, long hair or a short bob? And an angled bob? Is a bob with a shorter back easy to straighten?
A: Technically, longer hair is easier to straighten yourself at home, due to the fact that the weight of the hair already pulls the hair down for a smoother, straighter effect. If you have very curly hair this point may be almost irrelevant, though. Yet, although this might be technically easier to straighten, it will obviously take much longer.
It depends a lot on which kind of short bob you go for. If you go for a shaggy short bob, constructed with lots of razored and thinned out hair, things could get tricky. Hair that has been thinned out a lot tends to curl or wave easier, as the tips have been relieved of any bulkiness and weight.
This means that the lighter hair can easily flick or curl once a bit of humidity hits it. In this case, I would suggest applying a smoothing cream to the hair while it’s still wet, and also a silicone based product after the hair has been styled.
If you want to save a lot of time, effort and product, I’d suggest an inverted (A-line) bob with longer sides. The back should be really short, so that the hair automatically follows the line of the scalp. Then you’d only have to straighten the hair around the face and on the crown.
The hair around the face and crown tends to curve downward and inwards due to the form of the head. It’s usually the hair in the neck and resting on the shoulders that curls or waves. This is due to the fact that the hair is forced in different directions by the neck or shoulders.
Thus, choose an inverted bob which is really short at the back and not long enough at the front so that the side-sections don't touch your shoulders. Also, use shampoos, conditioners and styling products specifically designed to keep any humidity out. This way, you’re side-stepping all the potential problems that could mess up your straight hair.
See also:
Hair straightening
Angled bobs
How to cut a short inverted bob