Marble in acid demonstration. Apparatus used to demonstrate what happens when a marble chip (white, front left) and marble powder (white, front right) are added to acid. Marble is a form of calcium carbonate rock. It reacts with acid to produce hydrogen, which is be seen as bubbles in the solution. The marble powder reacts much faster than the chip as its surface area is much larger. Therefore the beaker on the right will fizz vigorously whilst the one at left will fizz much more gently.