Chapter 8 Our Planet Our Earth

Earth's atmosphere has five layers.

The atmosphere contains the troposphere, the mesosphere, and three other layers.

The most abundant gas in Earth's atmosphere is nitrogen.

The most abundant gas in Earth's atmosphere is nitrogen.

The stratosphere is the layer of the atmosphere that contains the ozone layer

The troposphere is the layer closest to Earth's surface where weather occurs

The top of the zone of saturation is known as the water table.

Relative humidity is so named because it measures how much water is in the air relative to how much could be there.

Less than one percent of Earth's freshwater is usable by humans

Ice accounts for 79 percent of Earth's freshwater.

The zone of saturation is below the water table.

Evaporation, transpiration and precipitation are steps in the water cycle.

Condensation is the process by which a gas changes to a liquid.

When water vapor condenses, drops of water form.

Water from puddles evaporates into the atmosphere.

 Igneous rocks are formed from cooled magma.

The rock cycle suggests that rocks are continually recycled into different forms.

Sedimentary rock is formed by compaction and cementation.

Surface processes that work to break down rock are called weathering.

Minerals are naturally occurring inorganic solids are part of the geosphere, with a definite chemical composition and orderly arrangement.

The crust is actually Earth's thinnest layer, even with the tall mountains on it.

The inner core of the Earth is a dense ball of solid iron.