1/3 of all classes in a major must be technical (this includes all electives, basic studies, etc.) 1/6 of all credit hours must be Junior/Senior in level and a technical class - Technical classes correspond to chemistry, physics, biology, engineering, etc.
For example: If your major is 123 credit hours, then 1/3 or 41 credits must be science. Also, 1/6 or 21 credits or more must be science and at Junior/Senior level standing.