Many scientific disciplines incorporate the concepts of waves, frequencies and periods. Physicists, engineers and astronomers study and work with wave energy. Examples of wave energy include light waves from a faraway galaxy, radio waves received by a cell phone and the acoustical waves from an orchestra. Regardless of the wave's source, the relationship between the wave's frequency and period are the same. A wave period is the time in seconds between two wave peaks and is inversely proportional to frequency.

Count the number of times the wave's peak occurs in a given time period. Use an oscilloscope to view the waveform.

Divide the number of waves by the length of time in seconds. This figure provides the wave's frequency. For example, assume 15 waves occur in 3 seconds. The frequency is 15 divided by 3, which equals 5. The units of frequency are Hertz.

Calculate the inverse of the frequency to obtain the wave's period. For example, 1 divided by 5 Hertz is equal to a period of 0.2 seconds.