A proposal under consideration by Prince Georges County would make a student's works for the public schools in Prince Georges County the property of the Board of Education, even if done on the student's own time and with use of their own materials. The law does not work that way.
While a work made for hire may apply to the teachers and educators employed by the County public school system, students are not employees of the public school system.
It is possible that the county could obtain rights to a student's work through a license or assignment. However, the better question, would be why would any student agree to such an arrangement?