Some magma, which is called lava when it reaches the earth’s surface, is shot high into the air from pressure and gasses that accompany many eruptions. The air cools the magma and hardens it while it still contains the gasses that were present in the magma as bubbles. The resulting rock is filled with an infinity of holes which were once gas bubbles in the airborne lava.
Explanation:
The most straightforward thanks to making a case for this can be as a result of some volcanic rocks (pumice specifically) are actually rock foam. like several artificial foams, it's created once an extremely viscous soften fluid at air mass is violently depressurised and cold, avoiding the liquid kind to settle in a very compact condition. The holes, as in any foam or sponge, are empty as a result of on the first liquid kind they were full of gasses. once an activity, those gasses left the rock and therefore the cavities are full of air.
