Chestub08, the answers to the questions that you originally posed are dependent upon your own personal and professional goals, and the industry and type of job that you envision for yourself. I earned my PhD in Materials Science at the University of Rochester back in the early 1990s. The requirements of that program were representative of most university PhD science and engineering programs at the time in terms of the credit hours required for graduation, which totaled 90 minimum. I had 72 hours of course work, and 18 official hours of research credits under my belt when I walked into my dissertation defense. In order to graduate, you must write a PhD dissertation and then successfully defend it in front of a committee that is composed of your thesis advisor, professors from the department in which you are enrolled, and at least one faculty member from outside your department. The apparently minor detail or writing and defending a thesis seems to be absent from most of the posts above, yet represents the majority of the time and effort required to earn the PhD. After the coursework is done, the real work begins. I actually did the calculations several years ago, and estimated that after earning my Bachelor's degree I spent an average of 60 hours a week for 5 years studying and working toward the PhD. I went straight through from the BS degree to the Master's, and then to the PhD before landing my first full time job. And I observed many people who studied part time for their advanced degrees. They had no life outside of work and school. It took them much longer to earn their degrees because they were employed in full time positions, and they were only able to juggle at most two classes per semester along with their job and their family. I can't imagine going back to school to earn my degree with the responsibilities and time constraints that are placed on me now.
How your potential employer views the Master's degree depends upon the requirements of the position and their expectations. If the job that you apply for lists a B.S. degree as the minimum educational requirement, then the M.S. degree will provide you with some distinction from the rest of the employment pool when you go for that first job. For the most part it should be considered as an advantage. And unlike the PhD, you are usually not viewed as being overqualified when you have the M.S. degree. If the minimum educational requirement for the job is a Master's degree, you will have to have it if you expect to even be considered for the position. What this usually means is that the employer is looking for someone with more specialized knowledge and ability than the B.S. degree candidate would normally be expected to demonstrate, and the bump in pay over a B.S. can be significant in this type of circumstance. If they typically hire lots of PhDs (think national lab for example) then the Master's degree is looked upon as more of a consolation prize that was given to someone who did not have the drive or ability to earn the PhD. Note that I do not condone this point of view. It was expressed directly to me by one interviewer, and I believe that it is not an uncommon sentiment in some work places.
Having the Master's degree will pay dividends for you as you progress forward in your career. In upper level management, it is sometimes a requirement of the position to have an advanced degree. And getting the Master's when you are younger is much easier than trying to earn it later in life. Lots of things like job responsibilities, family issues, and life in general have a tendency to get in the way of reaching that goal. If you plan to go into environmental or civil engineering, a PE is a worthwhile investment of your time and effort. Whatever your decision, I wish you good fortune.
Maui
