Earth Science Flashcards
What law states that in undisturbed sedimentary rocks, each layer is younger than the layer below it and older than the layer above it
Law of Superposition
A reliable way to tell the Earth’s age
Radioactive Dating
Describe the precambrian era (3)
- algae, sponges, worms
- too primitive to leave any fossils
- most rocks are igneous/ metamorphic
Describe paleozoic era (5)
- ancient life
- most fossils were found in layers of sedimentary rocks
- Devonian period
- appearance of reptiles
- land climate changed
Describe Devonian period(2)
- amphibians: first animal to succeed in adapting itself to breathe air
- land plants began to develop
Describe Mesozoic Era (2)
- formation of several continents
- dinosaurs
Describe Cenezoic Era (4)
- recent life
- volcanic activity
- warm blooded animals
- Northern hemisphere was covered in glaciers, which has signaled the start of Ice age
What are warm blooded animals?
Their temp does not change regardless of their surroundings (birds and mammals)
4 layers of earth
Crust, mantle, inner core, outer core
This is the thin outermost layer of the earth where all life on earth exists
Crust
Describe the outer core of the earth (2)
- liquid iron and nickel
- the intense heat makes the iron and nickel molten as a hot liquid
Describe the inner core of the earth
- Iron and nickel
- very dense due to intense pressure
What is an igneous rock? (2)
- when lava is cooled, it turns into igneous rocks
- obsidian
When magma cools quickly, crystals do not form and the minerals stay mixed in a glass-like solid
Obsidian
What is a sedimentary rock? (2)
- from deposits of the ocean which are made of travels, sand, plant and animal matter
- majority have a banded appearance due to differences in color, grain, etc
What is a metamorphic rock?
Tremendous pressure and high temp + igneous/ sedimentary rock
It is a crystalline solid w definite composition and structure
Minerals
What is the most abundant mineral?
Silicates
It is the tendency of a substance to split along certain planes which are determined by the arrangement of particles in its lattice
Cleavage
It occurs due to the tilt in earth’s rotational axis and it’s resolution around the sun
Seasons
Periodic rise and pull of the sea level due to the moon’s gravitational pull
Tides
It is the blocking of light by a heavenly body so that the source of life seems to disappear
Eclipse
Lunar vs Solar Eclipse
Lunar: when earth passes between sun and moon so that the earth’s shadow falls on moon
Solar: when the moon passes directly between sun and earth
Describe Troposphere(2)
- the layer we live
- weather
Describe Stratosphere
High concentration of ozone (filters out harmful uv rays)
Describe Mesosphere (2)
- lack of ozone
- meteors
Describe Ionosphere
- reflects radiowabes back to earth and makes long distance broadcast possible
Describe Thermosphere (2)
- the sun’s rays first hit
- satelite
True or False
Erosion is weathering
False
High temperature ______ rock and Low temperature _______ rock
Expands, contracts
It is used to indetify the age of a fossil
Carbon 14
Force of attraction: large object,_____ attraction. Small object, _____ attraction
High, low
