Amplitude and period are important in the study of music and acoustics; amplitude indicates the energy, or loudness, of a sound and the period determines its pitch (pitch, or frequency, is the inverse of the period). Amplitude is the height from the mean, or rest, value of the function to its maximum or minimum.The period is the distance required for the function to complete one full cycle. For the sine function, the amplitude is given by and the period is defined as. The same is true for a cosine function.mplitude is the height from the mean, or rest, value of the function to its maximum or minimum. The period is the distance required for the function to complete one full cycle.
Planaria. Planaria (Platyhelminthes) are free-living flatworms that live in freshwater. They are typically found under rocks and debris in streams, ponds, and springs. Planarians are interesting to study for a variety of reasons. First, planarians have bilateral symmetry with two nerves extending the length of the body, an enlarged brain (ganglion cell), and two eye spots. The eye spots are sensitive to light. Planarians move away from the light and are most active in the dark. Second, light and water current can be used demonstrate kinesis (change of speed) and taxis (change of direction).
Planaria are flatworms and members of the Platyhelminthes phylum. Planaria are often found in aquariums with uneaten food. The planaria won't hurt the fish, but they are a symptom of too much gravel containing too much uneaten food, and that is not good for fish.