1. The Earth and its oceans - 1.1. Structure of the Earth Flashcards
Number of planets orbiting the Sun
8
Largest object in the Solar System
the Sun
Force that keeps the Earth in orbit around the Sun
Gravitational pull
Position of the Earth around the Sun
Third
What creates the ideal temperatures for life to exist on Earth?
It’s position (as the third planet) from the Sun
How often does the Earth spin on its axis?
Every 24 hours
At what angle does the Earth spin on its axis?
23.5 degrees
What is the result of Earth being on a tilted axis?
Unequal exposure to light and heat throughout the year
Where is the intensity of the Sun greatest?
Near the Equator, between the Tropics of Cancer and Capricorn
Coldest regions on Earth?
Polar regions
Why are the polar regions the coldest on Earth?
Light intensity is very low compared to the equator
How long is takes the Earth to complete a full orbit of the Sun
365 1/4 days
What causes seasons?
Number of hours of daylight in the Northern and Southern hemispheres changes during the year.
Describe summer
Longer days and more exposure to energy from the Sun
Describe winter
Shorter days and less exposure to energy from the Sun
What is the Moon
A natural satellite that orbits Earth
How often does the Moon orbit Earth?
Every 27.5 days
What causes a strong gravitational pull between the Earth and the Moon?
Their closeness and the relatively large size of the Moon compared to the Earth
What does the gravitational pull between the Earth and the Moon affect?
The water in seas and oceans, creating tides
The Earth is a rocky planet, but the rock is only solid…
… at and near to the surface
What is the crust?
A thin layer of solid rock at the surface of the Earth
Describe the crust beneath the ocean
Greater density than continental crust, varies in thickness (3-10km)
Describe the continental crust
Lower density than crust below the ocean, varies in thickness (35-100km)
What is the mantle?
Thicker layer beneath the crust made of viscous molten rock called magma
What is the core?
Centre of Earth, below the mantle, made almost entirely of metal (iron). Solid in the center, molten around this.
What is the effect of the Earths’ core being made of iron?
Creates a magnetic field around the Earth
What do we use the magnetic field for?
Compasses, navigation
