Science test on Friday 10/10/14 Flashcards
(22 cards)
What is Earth mostly made of?
Rock
What is the Earth’s surface mostly covered with?
Water
What did planetesimals do as Earth formed?
crashed and combined
What happened to Earth as gravity crushed at its center?
It became round
What heated Earth as it formed?
radioactive material
What happened as Earth heated up?
inner rocks melted
Thin outermost layer of Earth
crust
Central part of Earth
core
layer beneath the crust
mantle
what makes up most of the Earth’s atmosphere today?
nitrogen and oxygen
What might have made up Earth’s early atmosphere?
carbon dioxide and water vapor
What probably changed Earth’s early atmosphere
volcanic gases
What might have helped change part of the early atmosphere?
elements in comets
How might water vapor have formed the first oceans?
It condensed
What might have brought some water to the first ocean?
icy comets
has lots of energy and can break apart molecules
ultraviolet radiation
protects us from the rays of the sun
ozone layer
may have started forming from molecules in Earth’s waters
life-forms
a way organisms make food by using the sun’s energy
photosynthesis
a gas that is added to air as organisms make food
oxygen
a gas that is removed from air as organisms make food.
carbon dioxide
what caused a global ocean to form when Earth cooled
rain
