Lesson 1 & 2 (8th)

Earth system

▪ The Earth system is all of the matter, energy, and processes

within Earth’s boundary.

▪ The Earth system can be divided into five main parts—the

geosphere, the hydrosphere, the cryosphere, the
atmosphere, and the biosphere.

Earth system

Geosphere

▪ The geosphere is the mostly solid, rocky part of Earth.

▪ The geosphere is divided into three layers based on

chemical composition: the crust, the mantle, and the core.

Geosphere: Layers

▪ Crust = The thin, outermost layer of the geosphere.

o The crust beneath the oceans is called oceanic crust.
o The continents are made of continental crust

▪ Mantle = is the hot layer of rock between Earth’s crust and

core. The mantle is denser than Earth’s crust.

▪ Core = is Earth’s center. The core is about twice as dense as

the mantle.
o The core is composed of a solid inner core and a liquid outer core.

Geosphere: Layers

Hydrosphere

▪ The hydrosphere is the part of Earth that is liquid water.

▪ 97% of all of the water on Earth is the salt water found in

the oceans.

▪ Oceans cover 71% of Earth’s surface.

▪ The hydrosphere also includes the freshwater in lakes,

rivers, and marshes. Rain and the water droplets in clouds
are also parts of the hydrosphere. Even water that is
underground is part of the hydrosphere.

Cryosphere

▪ Earth’s cryosphere is made up of all of the frozen water on

Earth.

▪ Include: sea ice, glaciers, ice shelves, and icebergs.

Atmosphere

▪ The atmosphere is mostly made of invisible gases that surround

Earth.

▪ The main gases that make up the atmosphere are nitrogen and

oxygen.
o About 78% of the atmosphere is nitrogen.
o Oxygen makes up 21% of the atmosphere.
o The remaining 1% is made of many other gases, including argon, carbon

dioxide, and water vapor.

▪ The atmosphere also absorbs some of the energy from the sun’s rays.

▪ Some gases in the atmosphere absorb and reflect harmful ultraviolet

(UV) rays from the sun, protecting Earth and its living things.

Biosphere

▪ The biosphere is made up of living things and the areas of

Earth where they are found.

Weathering

Unit 1: Lesson 2

Weathering

▪ The breakdown of rock material by physical and chemical

processes.

▪ Two kinds of weathering are physical weathering and

chemical weathering.

▪ Physical weathering is the process by which rock is broken

down into smaller pieces by physical changes.

▪ Chemical weathering is the breakdown of rocks by

chemical reactions.

Agents of Physical Weathering (use book to
read)

▪ temperature changes

▪ pressure changes

▪ plant

▪ animal actions

▪ water

▪ wind

▪ gravity

Agents of Chemical Weathering (use book to
read)

▪ Reactions with Oxygen

▪ Reactions with Acid Precipitation

▪ Reactions with Acids in Groundwater

▪ Reactions with Acids in Living Things