I have often sat by a campfire or in front of the fire in a fireplace and watched the sparks fly upward. I am sure that man has observed this phenomenon ever since he built the first fire for warmth or for a sacrificial offering. No one really questions as to why this happens; it just seems to be a natural thing for sparks to do. But when one considers that these sparks are small chunks of glowing carbon that are heavier than air, it requires some logical explanation as to why it happens. A fire generates a rising column of heated air that carries with it sparks and smoke and sometimes pieces of paper. The larger the fire, the more powerful is this updraft. As this heated air rises, the surrounding air rushes in to fill the resulting vacuum. In fact, I understand that a forest fire can generate its own wind as the air rushes in from all directions to provide the necessary oxygen to sustain the blaze. But why does this happen?
As one drives northward up the Napa valley of northern California past vineyards and the beautiful green hillsides, suddenly one notices some large, colorful objects that seem to hover motionless in the azure blue sky. As one gets closer, the objects increase in size and they are in motion. These are hot air balloons that are wafted by the gentle breeze of the summer day giving happy balloonists a bird's eye view of the beautiful valley. The force that keeps a hot air balloon aloft is the same that causes sparks to fly upward. This force was originally defined in a law expressed by a French physicist named Jacques Alexandre Cesar Charles about the year 1800. From his study of balloons he formulated Charles' Law which relates the volume and temperature of a gas. Simply stated, the volume of a gas varies directly as the temperature. In other words. if the temperature increases, so also does the volume increase; if a rubber balloon is heated, it becomes larger. But in order to fully understand why hot air rises, we must couple this law with Archimedes' Principle which relates volume, weight and density. This principle states that density and volume of a gas vary inversely, and since volume and temperature vary directly, we can put the two laws together and say that density varies inversely as temperature. So, the higher the temperature the less dense the gas will be. It is this difference in density that buoys up the hot air balloon.
Job is told by his friend, Eliphaz, that troubles are the lot of man just as sparks fly upward. He implies that this is because man has sinned and that trouble is God's punishment. But Job disagrees because he knows that he has done nothing to deserve his misfortunes and suffering. Finally, Job is justified in his innocence. We know that man is not destined to be troubled by God, but rather he is destined to be called and chosen for God's kingdom as surely as the "sparks fly upward."
