Topic 1

• What is the latitude of the Antarctic Circle?

  66.5°S
• What is the significance of the Antarctic Circle in relation to the Sun?

  It is the most northerly latitude where the Sun will not set on the northern hemisphere winter solstice.
• What is the latitude of the Arctic Circle?

  66.5°N
• What does the Arctic Circle represent in terms of sunlight?

  It is the most southerly latitude where the Sun will not set on the northern hemisphere summer solstice.
• What are the main components of the Earth's inner core?

  Solid iron and nickel.
• What is the state of the Earth's mantle?

  The mantle is semi-solid.
• What causes the movement of tectonic plates in the mantle?

  Convection currents.
• What is the shape of the Earth described as?

  An oblate spheroid.
• What is the composition of the Earth's outer core?

  Molten iron and nickel.
• How does the outer core contribute to the Earth's magnetic field?

  Moving electrical currents generate the Earth's magnetic field.
• What is the twinkling effect observed in stars caused by?

  Movements in the atmosphere subtly affecting the appearance of a star.
• What does "good seeing" mean in astronomy?

  It means the atmosphere is cool and still, resulting in less twinkle.
• What is the latitude of the Tropic of Cancer?

  23.5°N
• When is the Sun directly overhead at the Tropic of Cancer?

  On the summer solstice.
• What is the latitude of the Tropic of Capricorn?

  23.5°S
• When is the Sun directly overhead at the Tropic of Capricorn?

  On the winter solstice.
• What are the key characteristics of the Antarctic and Arctic Circles?

  • Antarctic Circle: Latitude 66.5°S, no sunset on winter solstice.
  • Arctic Circle: Latitude 66.5°N, no sunset on summer solstice.
• What are the main layers of the Earth and their properties?

  • Inner Core: Solid iron and nickel.
  • Outer Core: Molten iron and nickel, generates magnetic field.
  • Mantle: Semi-solid, causes tectonic plate movement via convection currents.
• What are the Tropic of Cancer and Tropic of Capricorn?

  • Tropic of Cancer: Latitude 23.5°N, Sun directly overhead on summer solstice.
  • Tropic of Capricorn: Latitude 23.5°S, Sun directly overhead on winter solstice.