Vertical Extent of the Atmosphere

From measurements by triangulations of the height of the aurora, (northern lights) the atmosphere extends to at least 800 miles above the earth's surface. There really is no top to the atmosphere as it grades into the Solar Wind. The density of the air, even at 200 miles, is so low that it is less than that of the best vacuum available in the laboratory. The highest clouds, noctilucent clouds are rarely seen, but typically occur at a height of 80 km or 50 miles above sea level.

Passenger jets regularly reach the top of the weather producing atmosphere, the troposphere, pass through the tropopause, and cruise in the lower stratosphere. The tops of tall thunderstorms rarely reach more than 55, 000 feet or 11 miles when they occur in the central USA. Tropical thunderstorms are commonly higher, usually 12 or 13 miles high, but are rarely severe except when in Hurricanes. The troposphere, the weather producing layer of the atmosphere, has a thickness of around 13 miles in the tropics to 9 miles in the Arctic in winter. The troposphere is really very thin; ten miles is not very far being only ten minutes drive on an Interstate.

The lower boundary of the Atmosphere

Most people think that the lower boundary of the atmosphere starts at the surface of the earth. Actually, air penetrates the top layers of soil, water, and snow.

Materials: State and local maps

One tumbler or small glass jar.

Water, soil, and snow (if available).