It is the second-smallest county by total area in Maryland. Notable waterways include the Choptank River and Tuckahoe Creek, as well as the man-made Williston Lake. Caroline County currently ranks seventh nationally in terms of land protected under the Ag Preservation Program.
Dry air contains roughly (by volume): All the above are relatively small, light, non-polar molecules, characteristics mimicking an ideal gas. At normal ambient conditions such as standard temperature and pressure, most real gases behave qualitatively like an ideal gas.
The thin envelope of air that surrounds our planet is a mixture of gases, each with its own physical properties. The mixture is far from evenly divided. Two elements, nitrogen and oxygen, make up 99% of the volume of air. The other 1% is composed of trace gases, the most prevalent of which is the inert gaseous element argon. The rest of the trace gases, although present in only minute amounts, are very important to life on earth.