Nice try though Take a glass with you into a swimming pool... pull it down into the water till you no longer can without it filling with water....Then go to the Lake (since your inland no ocean to do this with) and do the same experiment... Result... The glass holds it back no matter how much water is around it... make the glass taller and you run the risk of it breaking (Pressure is based on Depth.. not volume or width, those only change the bracing needs)Pharaoh;2480524; said:At the certain point that he is expanding the tank, the width of the tank will increase, which will increase the pressure exerted on the glass.