How do you measure the wavelength with a ripple tank?

You measure the length of 10 waves, then divide by 10. This increases the accuracy. You then need to find the magnification (m = I ÷ A), because the water enlarges the actual wavelength. To do this, you'd measure the length of another object (e.g. 13.5cm), then measure the length of the image projected (e.g. 21.5cm). Then, you'd do the image size ÷ actual size (e.g. 21.5 ÷ 13.5) to get the magnification (e.g. x1.6). Then, you would divide your wavelength by the magnification (e.g. 5 ÷ 1.6 = 3.125).