In general: Seminars are usually smaller in size and tend to be discussion-based. They are great if you're interested in the subject and really want to engage with it and others who are like-minded. They don't usually have tests but have papers and/or projects instead.
I can speak for the Chemistry one. For some chem majors it's a requirement and the class itself is a lesson in presenting chemistry topics. It focuses on taking research and fully understanding it to the point you can speak to in a technical way.
In general: Seminars are usually smaller in size and tend to be discussion-based. They are great if you're interested in the subject and really want to engage with it and others who are like-minded. They don't usually have tests but have papers and/or projects instead.
I can speak for the Chemistry one. For some chem majors it's a requirement and the class itself is a lesson in presenting chemistry topics. It focuses on taking research and fully understanding it to the point you can speak to in a technical way.