English: A water wave analogue of the Casimir effect. Two parallel plates are submerged into dyed water contained in a sonicator (i.e., an ultrasonic bath). When the sonicator is turned on waves are excited imitating vacuum fluctuations; hence, the plates attract to each other as in the quantum Casimir effect. For details see, e.g., [B. C. Denardo, J. J. Puda, and A. Larraza, "A water wave analog of the Casimir effect" American Journal of Physics, Vol. 77, Iss. 12, pp. 1095 (2009); https://dx.doi.org/10.1119/1.3211416]