Explaining time signature is hit and miss with my 5-6 year-olds. I was struggling with the concept of the measure line with my first student of the day and failed miserably. Even when we worked in the writing book and drew the measure lines I felt I was not connecting. The next student was the same age and we were doing the same lesson. I remembered copying learning tools from Susan Paradis called rhythm blocks. This seemed to do the trick.