What method can be used for collecting the gas after reacting sulhpuric acid and magnesium?

The traditional method was to fill a cylinder with water and invert it on top of a form with a hole in the side and one in the top, also under water. Run some rubber tubing from the reaction vessel into the hole in the side of the form. The hydrogen then bubbles up through the cylinder depressing the water level as it does so. This enables you to measure the volume of hydrogen given off.