trying to figure out if tracker can be used to determine useful curriculum learning. seems to be possible to determine the velocity of wave when a length is assumed.
say if S1S2 is 0.3m
since we know the video i n phase sources, by observing the bright light at S1 and S2 happens together.
the centre line, say length is set at 4.659E-1 m from S1 to P where P is a bright interference.
similarly, S2P is roughly 4.734E-1 m
by stepping the video,for simplicity 4 steps result in t = 0.133 s = T.
thus, f = 1/T = 7.52 Hz
the wavelength is determined as 1.097E-1 m as shown
therefore, using v = f.lambda
                      v = 7.52(1.097E-1)
                      v = 0.825 m/s
[color=red][b]is this correct?[/b][/color]

took 3 videos
real setup video taken by lookang

in phase sources video taken by lookang

in anti-phase sources video taken by lookang