origin

• What is the focus of the study material?

  The origin and structure of the Earth
• What do scientists study to understand the universe?

  Galaxies, stars, and comets
• What principles do scientists use to study the universe?

  Hypotheses, models, theories, and laws
• What are the four scientific ideas mentioned?

  • Hypothesis: Testable proposition
  • Model: Representation of ideas
  • Theory: General principle explaining phenomena
  • Law: Description of observed phenomena
• What theories are to be filled in the assignment table?

  • Big Bang Theory
  • Steady State Theory
  • Oscillating Universe Theory
  • Nebular Hypothesis and Condensation Theory
• What does the Big Bang Theory propose?

  A massive blast created the universe
• Who first suggested the Big Bang Theory?

  Georges Lemaitre
• What is the main idea of the Steady State Theory?

  New matter is continuously created
• Who formulated the Steady State Theory in 1948?

  Fred Hoyle, Thomas Gold, Hermann Bondi
• What does the Oscillating Universe Theory suggest?

  The universe undergoes cycles of expansion and contraction
• Who first proposed the Oscillating Universe Theory?

  Albert Einstein
• What does the Nebular Hypothesis explain?

  The solar system formed from a gaseous atmosphere
• Who published the Nebular Hypothesis in 1755?

  Immanuel Kant
• What is the thickness range of the Earth's crust?

  5 to 70 km
• What is the mantle composed of?

  Molten silicate rocks
• What is the core of the Earth known for?

  It is the hottest layer and source of the magnetic field
• What are the two layers of the Earth's core?

  Outer core and inner core
• What are the subsystems of the Earth?

  • Lithosphere: Rocky crust, inorganic minerals
  • Hydrosphere: All water on Earth
  • Atmosphere: Air surrounding Earth, composed of gases
  • Biosphere: All living organisms
• What is the composition of the atmosphere?

  79% Nitrogen, fewer than 21% Oxygen
• What does the biosphere encompass?

  All living organisms on Earth