Topic 1

Question 1

What shape is the earth

Answer 1

It is what we call an oblate spheroid

Question 2

What causes the earth to be an oblate spheroid

Answer 2

. The Earth spins on its axis causing it to bulge in at the equator due to the centrifugal force of the spin.

Question 3

what is a terrestrial planets

Answer 3

compact, rocky surface

Question 4

what is the largest of our Solar System’s terrestrial planet

Answer 4

earth

Question 5

what makes up 70% of the earth

Answer 5

water

Question 6

What is the crust

Answer 6

The crust is the outermost layer of the Earth. It is solid and is also the thinnest layer

Question 7

what is continental crust?

Answer 7

Continental crust make up the continents and are older. These are made of low-density rocks such as granite and is between 30km and 70km.

Question 8

What is oceanic crust?

Answer 8

Oceanic crust is younger and is between 5 km and 10 km thick and these are found on the ocean floor. These are made of high-density rocks such as basalt.

Question 9

What is the mantle?

Answer 9

The mantle lies below the crust and is around 2900km thick which is half way to the centre and makes up about 80% of the Earth’s volume. It consists mainly of silica and minerals of iron, magnesium and other metals.

Question 10

what is the upper mantle?

Answer 10

The upper mantle is made up of semi-molten (melted) rock, called magma and is about 870°C. As it is liquid it has thermal convection currents driving the sideways motion of the tectonic plates.

Question 11

what is the lower mantle

Answer 11

The lower mantle is 2200°C-3700°C and is solid.

Question 12

Why is the lower mantle solid even though it is at a higher temperature?

Answer 12

The weight of the rest of the planet above it means the pressure is too high for it to be a liquid.

Question 13

What is the core?

Answer 13

The core extends to just over half the Earth’s radius and is made from iron and nickel.

Question 14

What is the outer core and what temp is it?

Answer 14

The outer core is liquid and has a temperature of about 500oK. It is liquid and electrical currents flowing through it generates the Earth’s magnetic field (magnetosphere

Question 15

what is the inner core?

Answer 15

The inner core is theorised to be solid and has a temperature of about 550oK (which is the same temperature of the Sun’s photosphere

Question 16

what is latitude?

Answer 16

Latitude is a co-ordinate on the Earth’s surface that measures how far north or south a position is

Question 17

where is latitude measured from?

Answer 17

. It is measured from 0° at the Equator to 90° at the North Pole. Co-ordinates south of the equator are preceded by a minus sign, so the South Pole would be at -90°.

Question 18

What is longitude?

Answer 18

Longitude is a co-ordinate on the Earth’s surface that measures how far west or east a position is.

Question 19

how can longitude be measured?

Answer 19

A circle can be divided into 360° but for longitude we measure co-ordinates from 0°. Co-ordinates are located at up to 180° west or east of this location.

Question 20

what does subtended mean?

Answer 20

Subtend means to be at the opposite of an angle or an arc and is formed when viewing something from an external point.

Question 21

where are angles of longitude and latitude subtended from?

Answer 21

Latitude and longitude are actually angles subtended at the centre of the earth.

Question 22

what is the equator?

Answer 22

A line around the widest part of the Earth dividing the Earth equally into the northern and southern hemispheres. Latitude 0o

Question 23

What is the prime meridian

Answer 23

Prime meridian: The line splitting the Earth top to bottom through the centre. The position of Longitude 0ois measured from the north-south line that intersects Greenwich, London.

Question 24

what are the earths pole?

Answer 24

Poles: Earth poles are the highest and lowest points on Earth. Latitude 90o Longitude 0o

Question 25

what is the arctic circle?

Answer 25

Arctic Circle – The most northerly latitude (66.50 N) from which you can see the Sun rise and set on every day of the year.

Question 26

what is the anarctic circle?

Answer 26

Antarctic Circle – The most southerly latitude (66.50 S) from which you can see the Sun rise and set on every day of the year.

Question 27

what is the tropic of cancer?

Answer 27

Tropic of Cancer – The Sun lies directly above here (latitude 23.5o N) on the northern hemisphere’s summer solstice (21st June) when the Earth has it’s maximum tilt towards the Sun.

Question 28

what is the tropic of capricorn?

Answer 28

Tropic of Capricorn – The Sun lies directly above here (latitude 23.5o S) on the northern hemisphere’s winter solstice (21st December) when the Earth has it’s maximum tilt away from the Sun.

Question 29

what is the spring equinox

Answer 29

Spring equinox– Around 21st March, the Sun directly lies over the equator

Question 30

what is the autmn equinox?

Answer 30

Autumnal equinox – Around 23rd September, the Sun directly lies over the equator.