Oceans cover 3/4 of the earth's surface, while air makes up the entire sky up to 1,000 km of altitude (1/2 of the air stays in the lower 5 km). That is an pretty large amount of water and air, one would think. But just look at this enlightening computer graphic, which shows us that, compared to the total mass of the earth, water and air are very small parts of our planet.
On the left, the little blue ball represents ALL the water on our earth (only 1/1000 of its volume), and on the right, the small white ball shows the amount of air that surrounds our planet.