Earth system

• What is a system composed of interacting components that form a complex whole?

  A system
• How does the human body exemplify a system?

  It is composed of many organs that interact to produce a living human.
• What role does blood play in the human body system?

  Blood nurtures the stomach, which helps provide energy to maintain the blood.
• What drives the flow of matter and energy in the human body system?

  The ingestion of food and inhalation of oxygen.
• How are waste products released from the human body?

  Through urine, feces, sweat, and exhaled breath.
• What happens to energy used in the human body?

  Some energy is used for respiration and motion, and the remainder is released as heat.
• How do humans interact with their environment?

  Like a Stone Age hunter-gatherer living in a small valley.
• What is an ecosystem composed of?

  Plants and animals that interact with their physical environment.
• Why is it important to study smaller systems within the human body?

  To understand how they contribute to the overall human system.
• What are the four major systems of the Earth?

  Geosphere, hydrosphere, atmosphere, and biosphere.
• How is a volcanic eruption part of a system?

  It is driven by mantle convection and movements of tectonic plates.
• What happens to ash from a volcanic eruption?


  It cools the Earth and becomes a component of the climate system.
• What powers Earth's surface systems?

  The Sun.
• How long will Earth continue to receive solar energy?

  For another 5 billion years or so.
• What are the fundamental cycles in Earth systems?

  The water, nitrogen, carbon, and rock cycles.
• What is always conserved during energy and material cycles?

  Matter.
• What is unique about Earth compared to other planets?

  It has rain falling from clouds and water that runs over the land.
• What is the geosphere?

  The solid Earth, including its rocks and minerals.
• How did the Sun form?

  Gravity pulled material toward the swirling center while rotational forces spun material into a thin disk.
• What are planetesimals?


  Rocky clumps that formed from small grains sticking together.
• What happened to Earth as it coalesced?

  Rocky chunks and planetesimals collided, generating heat.
• What caused the early Earth to become molten?

  Collisions with asteroids, comets, and planetesimals, along with radioactive decay.
• How is the geosphere structured today?

  It consists of three major layers: a dense metallic core, a less dense rocky mantle, and an even less dense surface crust.
• What is the thickness of the outer core?

  About 1400 miles thick.
• What is the composition of the inner core?


  Primarily iron.
• What happens to temperature with depth in the Earth?

  The temperature increases with depth.
• What characterizes the outermost mantle?

  It is cool, strong, and hard up to a depth of about 100 kilometers.
• How does the mantle behave beyond 100 kilometers depth?

  The rock becomes soft, plastic, and flows slowly.
• What is the lithosphere?

  The outer part of Earth, including both the uppermost mantle and the crust.
• How thick is the lithosphere on average?

  About 100 kilometers thick.
• What theory explains the movement of tectonic plates?

  The theory developed in the 1960s that tectonic plates are derived from the broken lithosphere.
• How fast is North America drifting toward China?

  About as fast as your fingernail grows.
• What happens when Asia and North America collide in the future?

  They may crumple the edges of the continents and build a giant mountain range.
• What is the hydrosphere?

  The liquid water component of the Earth.
• What percentage of Earth is made up of oceans?

  71 percent.
• What percentage of Earth's water is contained in the oceans?

  97.5 percent.
• How does ocean currents affect global climate?

  They transport heat across vast distances.
• What percentage of Earth's water is frozen in glaciers?

  About 1.8 percent.
• How much of Earth's land surface is covered by glaciers?

  About 10 percent.
• What is the significance of freshwater on Earth?

  It is essential to life, despite being a small proportion of total water.