Natural

• The Earth is one of eight planets orbiting the Sun in the Solar System
• The Sun is the largest object in the Solar System and it has the greatest gravitational pull on other objects, particularly planets, in the Solar System
• Gravitational pull keeps the Earth in orbit around the Sun
• The Earth's position as the third planet from the Sun helps create the ideal temperatures for life to exist on the Earth
• As the Earth orbits the Sun, the Earth is also spinning on its axis every 24 hours (one day)
• The Earth spins on its axis at an angle of 23.5 degrees, so for most of the year there is unequal exposure to light and heat from the Sun on the surface of the Earth
• The intensity of the Sun is greatest near the Equator and between the Tropics of Cancer and Capricorn
• Light from the Sun only reaches the southern limit of the Arctic Circle, resulting in no light on any of the Earth's land or ocean north of this line
• The Antarctic Circle, near to the South Pole, is completely exposed to light from the Sun
• At the poles, there is very limited heating from light from the Sun, meaning that the polar regions are the coldest on the Earth
• The Moon is a natural satellite that orbits the Earth every 27.5 days
• The closeness of the Moon to the Earth, relatively large size of the Moon compared to the Earth, causes a strong gravitational pull between them
• The gravitational pull between the Earth and the Moon also has a large effect on the water in seas and oceans, causing tides
• The Earth takes 365 ¼ days to complete one full orbit around the Sun
• As the Earth moves around the Sun, the Earth's axis continues to point in the same direction
• Longer days, by which we mean longer periods of daylight, and greater exposure to more energy from the Sun, cause warming of the Earth's surface in summer months
• Shorter days, with less exposure to energy from the Sun, cause cooler weather in winter months
• Modelling day and night

  1. Use a torch (lamp) and globe

  2. Turn the Earth anticlockwise on its axis

  3. Move the Earth slowly around the Sun in a large circle

  4. Rotate the Earth on its axis at different positions in its journey round the Sun

  5. Observe how the light reaches the North Pole or South Pole only when that Pole is pointing towards the Sun

  6. Investigate the difference in the length of the day in both hemispheres as the Earth moves around the Sun

  7. Discuss how the length of day changes near to the poles

  8. Discuss the intensity of light near the poles compared with the intensity of light near the equator
• An important effect of the iron in the Earth's core is that this creates a magnetic field around the Earth
• We use the Earth's magnetic field for navigation
• A compass uses a magnet that can freely rotate to align with the Earth's magnetic field and point to the magnetic North Pole
• The Earth's magnetic field is important in helping some species to navigate during migration
• The Earth


  • It is a rocky planet
  • The rock is only solid at and near to the surface
  • The crust beneath the ocean has a greater density and varies in thickness from 3 to 10 km
  • Continental crust has a lower density and usually varies in thickness from 35 to 40 km, though continental crust can be as much as 100 km in thickness
  • Beneath the crust is a much thicker layer (the mantle) which is made of viscous molten rock called magma
  • Beneath the mantle is the core, made almost entirely of metal, particularly iron. The core is solid in the centre and molten around this
• Theory of plate tectonics


  A theory developed in the 1960s that helps explain the formation of some of the important features on the Earth's surface and how the continents move
• Convection current


  The transfer of thermal energy (heat energy) by the motion of fluid
• Tectonic plates


  Large sections of crust
• Supercontinent


  A large landmass thought to be broken up into several of the current continents
• Pangea


  A large landmass thought to have broken up to create all the current continents
• Divergent plate boundary


  Two tectonic plates move apart, forming new land between them
• Convergent plate boundary


  Two tectonic plates move towards each other
• Transform plate boundary


  Two tectonic plates try to slide past each other
• Lava


  Molten rock that erupts from the Earth's crust
• Earthquake


  A sudden shaking of ground, usually caused when two plates suddenly slip against each other
• Volcanic islands


  Islands formed when volcanic eruptions result in the formation of an island or group of islands
• Volcanoes


  Part of the Earth's crust from which lava erupts
• Mid-ocean ridge


  Mountain ranges formed deep in the ocean that extend for hundreds of kilometres either side of the parting plates
• Hydrothermal vent


  Cold ocean water seeps into the Earth's crust and is superheated by underlying magma; this water is forced through vents (gaps) in the ocean floor and as it cools dissolved minerals solidify and form a chimney-like structure
• Minerals


  Nutrients that are needed by living organisms; examples include calcium and iron
• Subduction


  The downwards movement of one plate beneath another
• Tsunami


  A series of fast-moving waves with a long wavelength, created by ocean floor displacement or landslide