How to calibrate the spirit Level?
Bubbles always float on the surface of the water. If the tube is straight, the bubbles will always float on both ends. Only when the tube is absolutely horizontal will the bubbles stay in the middle. This straight tube is useless. Only the standard tube made of curved, curved pipe and leveling into different angles, bubbles will stay in different positions. The greater the radius of curvature of the level tube, the higher the accuracy of the level gauge.