"What do you do in the morning?"
Translation:오전에 뭐 해요?
Great question! 오전 refers to the whole AM aka all 12 hours from midnight to noon. 아침 more loosely refers to the waking hours of the morning, roughly 6 am to noon. I will say meaning varies slightly from person to person. For example my boyfriend only considers 6 am - 10 am to be 아침. It's like trying to define exactly when afternoon becomes evening. Hope this helps!
• 아침 = morning, period of the day from sunrise (dawn, 새벽) till midday (noon, 정오).
However in common usage, 아침 is often used to refer to the morning period before the working day starts. Hence, the "early morning" expression.
• 오전 = a.m., period of the day before noon (It includes the period just past midnight till dawn).