2.3.Reflective Index of Water The similar problem shown above may appear here too.Furthermore,the water container may case problem either.How to avoid that? 3.Instruments and Cautions 3.1.Instruments 3.2.Hints Since the peak value and zero position are determined manually,you may want to adjust the signal of the digital oscilloscope,so that the peak height of the optical signal is the same as that of the reference signal.2.3．Reflective Index of Water The similar problem shown above may appear here too. Furthermore, the water container may case problem either. How to avoid that? 3. Instruments and Cautions 3.1．Instruments 3.2．Hints Since the peak value and zero position are determined manually, you may want to adjust the signal of the digital oscilloscope, so that the peak height of the optical signal is the same as that of the reference signal