A float will ride the tank's next run: lifting 2 cm above calm level, dipping 2 cm below, one full bob every 0.5 s. The lab sheet's second grid is labeled displacement (cm) against time (s), and the order reads: draw the float's story.
The construction routine carries over almost whole; only the horizontal step changes its meaning, from a length to a time.
Picture the real float first: up 2 cm, down 2 cm, one complete bob every 0.5 s, over and over above its own patch of water.
The lab sheet wants both of those facts in one drawing: how far the float swings, and how much time one bob takes.
Mark the swing range: peak tops at +2 cm, trough bottoms at -2 cm.
Place the first peak at a convenient time. Step one period, 0.5 s here, along the time axis and mark the next peak: every peak sits one period after the one before.
Halfway between two peaks, mark a trough bottom: troughs sit half a period after peaks.
Join the marks with one smooth curve through the zero line, and check the finished sketch against both givens: peak height off the displacement axis, peak spacing along the time axis.
Construct a displacement-time graph of one float with amplitude 7 cm and period 8 s, first peak at 2 s. Where do the next peak and the first trough after it sit?
Peaks sit one period apart.
2 + 8 = 10
Troughs sit half a period after peaks.
Half of 8 s is 4 s, so the trough sits at 6 s, at -7 cm.
The next peak sits at 10 s (top at +7 cm), and the first trough sits at 6 s (bottom at -7 cm).
Anselm constructs a displacement-time graph of a bobbing float with amplitude 4 cm and period 2 s, placing the first peak at 0.5 s. Enter the time, in s, of the next peak.
Beata constructs a displacement-time graph of a wave with period 4 s, placing a peak at 1 s. Enter the time, in s, of the first trough after that peak.
Dilys's sketch must follow one point of a wave through time. Which horizontal axis label does her grid need?
A construction task gives period 5 s, with the first peak placed at 0.7 s. Enter the time, in s, of the next peak.
A construction task gives period 6 s, with a peak placed at 1.5 s. Enter the time, in s, of the first trough after that peak.
Cosmo's finished graph must show a period of 4 s, but his peaks sit 8 s apart. Which fix makes the graph correct?