The main difference between the two is just the subject matter.
A BA is a bachelor of arts, so for example, will be used for the humanities, English, languages and the arts.
A BSc is a bachelor of science, so will be the sciences, maths and other science based courses.
Due to this split in subjects, a BA will have more of a focus on skills like communication and critical thinking whereas a BSc would be more focussed on logic and numerical or scientific skills.
Sometimes a BA will have a broader scope of content whereas a BSc will be more specific or specialised.
What subject are you asking this in reference to?
Lizzie (3rd year BSc Mathematics and Philosophy at the University of Sheffield)