RHYTHM;
This word rhythm means arrangement of tones according to their various time-values. It is the control of time. - the difference, dissimilarity, and peculiarity of short and long time values, and of the accented and unaccented( heavy and light) pulses (that is Beats) Listen to the song "Yesterday", "Far away", Here to stay"…etc.. This repeating rhythm makes to move the song further. The word Rhythm signifies arrangements. Arrangements of tone according to their various time-values .
TEMPO:
Musical picture is always changing not constant. It is panoramic. We don’t hear a piece of music all at once. But as a panorama of successive sounds. Tempo (an Italian word) is considered as "the rate of speed" of the beat of music which scroll passes before one's mind, and is measured by the number of beats per minute. In other words, tempo refers to the speed or frequency with which the pulses occur. A beat may be slow or fast. Human perception perceives a range of tempo speed from about 30 to 240 beats per minute. "Romantic" songs tend to have a medium tempo, while dance music may range from slow to fast tempo. March music reflects a comfortable marching pace -- about 120 beats per minute.
TIME:
Time is one and the same thing in music that is true everywhere in nature. It scrolls or passes while a piece of music is played ,sung or read .Time is the canvas upon which the musical images are drawn --- in melodic lines. Bass is like the shadow given for this image.