The main difference between work experience and a work placement is usually the time each requires.
Work experience may be either a one-off short period or something undertaken once a week but again for a couple of weeks maximum.
A work placement is generally part of a college or university course, such as an undergraduate degree, and can take between six months and a year to complete. For example, student nurses are assigned to a hospital or other medical setting for a mandatory work placement as part of their training. Similarly engineers may complete a years placement in order to gain practical hands-on experience sandwiched in between their learning.