Ay [T1] - Planet Earth Flashcards
What are the 4 layers of the Earth?
The crust, the mantle, the outer core and the inner core
What is the mean diameter of the Earth?
13,000km
What is the mean radius of the Earth?
6,500km
Which layer of the Earth is responsible for the Earth’s magnetic field?
The outer core
What is the mean radius of the Mantle?
3,500km
What is the inner core made of?
Solid iron and nickel
What is the outer core made of?
Liquid iron and nickel
Which layer of the earth makes up 80% of earth’s volume?
Mantle
What shape is the earth?
Oblate spheroid
What is the equation for the circumference (of the earth)?
Circumference = 2 π r
What is the equation for the volume (of the earth)?
V = 4/3 π r³
Which directions does latitude measure?
North (which is positive) and South (which is negative)
Which directions does longitude measure?
East (which is positive) and West (which is negative)
Define the equator
The zero point of latitude, north and south are measured from here
Define the Prime Meridian
The zero point of longitude, east and west are measured from here.
The Prime Meridian passes through the Observatory of Greenwich
Define the Arctic Circle
The most southerly point in the northern hemisphere where there is a period of 24 hour sunlight
Define the Antarctic Circle
The most northerly point in the southern hemisphere where there is a period of 24 hour sunlight
Why do stars twinkle?
Different densities of air in the Earth’s atmosphere result in the refraction of light as it passes through these layers
Define skyglow
Extra brightness in the night sky
Why is the sky blue?
Light is made up of different sized wavelengths (therefore different colours).
The longer wavelengths for red, orange, yellow and green will pass straight through the atmosphere, whereas the shorter wavelengths for blue, indigo and violet get absorbed by gas molecules.
Rayleigh scattering then occurs, meaning everywhere we look, the blue light hits our eyes and makes the sky appear blue.
What do you need to include when writing locations in latitude and longitude?
One of the 4 Cardinal Points (N, E, S, W)
What latitude is the Tropic of Cancer at?
23.5°N
What latitude is the Tropic of Capricorn at?
23.5°S
What is the definition of the Tropic of Cancer?
Most northerly point on the Earth where the Sun will be directly overhead on the summer solstice
What is the definition of the Tropic of Capricorn?
Most southerly point on the Earth where the Sun will be directly overhead on the winter solstice
