[animation of trumpets playing "La Cocarocha, narrator speaking:] Just as a drill sergeant calls cadence for marching ,[animation of drill sergeant commanding notes] rhythm calls cadence for music. There are two parts to time, or rhythm in music. [animation of clock] The first is beat, the other is measure. Just like minutes in an hour, there are a certain amount of beats in a measure. Time in music is expressed in beats per measure. We can begin to understand about rhythm by simply counting to four. [animation of clef] As we count, we are counting beats. Each four beats completes a measure. On the staff the begin and end of each measure is marked by a vertical line like this. As we count from one to four the one beat is a little louder. This is to emphasize the beginning of the measure. Try tapping your foot along with the beat as you count aloud. Tap your foot a bit heavier on each count of one. 1,2,3,4. 1,2,3,4. 1,2,3,4. 1,2,3,4. A measure with four beats is in 4/4 time. The time is noted on the staff just after the clef. 4/4 time is also called common time. Often a "c" for common time is used to indicate 4/4 time is to be used, but 4/4 is not the only musical time. Any number of beats per measure is possible. Here is an example of 3/4 time. As you can see, there are only three beats per measure in 3/4 time. 1,2,3. 1,2,3. 1,2,3. 1,2,3. Tempo is simply the speed of the beats, or how fast you go. Here is the example of 4/4 time we just heard, and here is 4/4 time at a fast tempo, or as some might say "up tempo". Lets review what we have learned about musical time. Musical time is divided into measures, with a certain number of beats per measure. Tempo is the speed of the beats.