Large plastic tank, perfectly sealed, ideal for optical actions.
Just fill the tank with water, use a laser pointer and visualise the path of the light beam to highlight phenomena such as refraction, reflection or even the deviation of a light beam by a gradient index (adding sugar to the bottom of the water).
Dimensions (LxHxD): 480 x 150 x 25 mm
The tank is held in place by a plastic base and can not be knocked over.