振幅: maximum displacement from the center
Read 振幅 from the center of a simple oscillation. Distinguish moving the drawing upward on a screen from changing the size of its displacement.
Read 振幅 relative to the center
振幅, read しんぷく, means amplitude. 実験では振幅の変化をグラフに記録した。 says that changes in amplitude were recorded on a graph during the experiment.
For the simple oscillation considered here, amplitude is the largest displacement magnitude from the center. It differs from the full span between the upper and lower extremes.
Distinguish amplitude from the full span
In a drawing using one length unit, a center at 0 and extremes at 3 and minus 3 give an amplitude of 3. The full span of 6 is not the amplitude.
First find the center, then read the maximum displacement to one extreme. The bottom of the screen is not an arbitrary replacement for that reference.
Moving the drawing preserves its amplitude
Move that drawing upward so its center reads 10 and its extremes read 13 and 7. Each extreme remains 3 from the center. Only the drawing’s displayed position has changed.
A larger displayed center value does not by itself indicate a larger amplitude. Check whether the displacement from the center to an extreme changed.
Is the amplitude 6 when a drawing has a center at 0 and extremes at 3 and minus 3?
Show the answer and why
No. Its amplitude is the maximum displacement magnitude of 3 from the center. Six is the full span between the extremes.