Are block schedules effective for students?

I'm a 4th grade homeroom instructor. I teach four core subjects. My students seem to really enjoy the modern learning strategies that are utilized in my clroom; they have fun. Each day is allocated for one subject for example, three science periods on Monday, three social studies periods on Tuesday, etc. Because of such a strong focus on one or two subjects each day, my students really get into the lesson. However, I want to know if it is detrimental to longterm comprehension of the content if each subject is taught during only one segment of the week. Do you know if breaking up each subject and spreading it throughout the week is more effective in terms of mastering the content? Your time and thoughts are appreciated.