How do geologists determine the age of rocks?
Geologists determine the age of rocks by measuring their radioactivity with special detectors.
What significant events occurred during the Hadean eon?
During the Hadean eon, the Earth was hot, had many volcanoes, and experienced collisions with comets and meteors. There was no oxygen in the atmosphere.
What important development in the Earth's atmosphere happened during the Proterozoic eon?
During the Proterozoic eon, oxygen began to build up in the Earth's atmosphere.
Describe how the continents changed during the Phanerozoic eon.
During the Phanerozoic eon, animals became common, and the continents drifted together to form the supercontinent Pangaea, which later split into the continents
How old is the Earth?
Dating by radioactivity shows that the Earth is about 4600 million years old.
True or False: A fossil is the remains of a living thing that has been preserved for millions of years.
True
True or False: The first mammals appeared at about the same time as dinosaurs.
True
True or False: Dinosaurs were the most important animal group during the Mesozoic era for nearly 200 thousand years.
False. Dinosaurs were there for 200 million years!
True or false: Most fossils are found in layers of igneous rock.
False. sedimentary rock
What do we call the temperature, winds, and other conditions of the atmosphere?
weather
Who measures the conditions that describe the weather?
Meteorologists
What forms when air rises and cools?
clouds
What is the ideal humidity level for comfort?
45%
What do we call strong winds and heavy rainfall?
storms
