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How did the moon form?
Material was knocked loose when Earth collided with another object
What is a comet?
A ball of dust, gas, and ice that orbits the sun.
What gases from volcanoes and comets were in the SECOND atmosphere?
Carbon dioxide, water vapor, and nitrogen
How many years ago did Earth form?
4.6 Billion years ago
What did scientists use to find the age of the moon rocks?
radioactive dating
What gases were included in the FIRST atmosphere?
Hydrogen and Helium
What gases from organisms were in the SECOND atmosphere?
Oxygen
Sequence: ___ Ozone layer forms
3
What do scientists think the Earth began as?
a ball of dust, rock, and ice
Earth's FIRST atmosphere was blown away by what?
Particles from the sun.
How many years ago did many organisms begin using energy from the sun to make food?
2.5 billion years ago
Sequence: ___ Earth loses its first atmosphere
1
How old are the oldest rocks ever found on Earth?
about 4 billion years old
At first, Earth's atmosphere was too hot for water to stay liquid. All water remained as what?
Water vapor
What part of the atmosphere was developed to black ultraviolet rays of the sun?
Sequence: ___ Volcanoes and collisions with comets add water vapor to the atmosphere
2
Could life have existed on Earth if there was no liquid water? You must explain!
No. Life needs liquid water to exist, if there is no water, there is no life!
During which time did Earth's rock cool and harden?
Precambrian Time
Scientists have found fossils of single-celled organisms in rocks that formed how many years ago?
3.5 billion years ago
How would Earth's atmosphere be different if organisms capable of photosynthesis had not evolved?
There would be no oxygen in the atmosphere