Chapter 8 Our Planet Our Earth

Chapter 8

Our Planet Our Earth

Our Atmosphere

• 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.

Our Atmosphere

• 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

Water

• 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.

Water

• 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.

Water Cycle

• 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.

Rock

•  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.

Rocks and Minerals

• 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.

Layers of the Earth

• 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.