Which allowed scientists to determine that Earth was at least 4.3 billion years old?(1 point)
Responses
chemical reactivity of zircon ions
chemical reactivity of zircon ions
the radioactive decay of uranium to lead
the radioactive decay of uranium to lead
the electrical conductivity of uranium ions
the electrical conductivity of uranium ions
magnetic field surrounding zircon
magnetic field surrounding zircon
the radioactive decay of uranium to lead
Which evidence of the giant impact theory suggests that Earth and the moon may have once been in the same place?(1 point)
Responses
The amount of water on the moon and on Earth is similar.
The amount of water on the moon and on Earth is similar.
The temperatures on Earth and on the moon are similar.
The temperatures on Earth and on the moon are similar.
The composition of moon rocks and some Earth rocks are similar.
The composition of moon rocks and some Earth rocks are similar.
The type of gases in the atmospheres of Earth and the moon is the same.
The composition of moon rocks and some Earth rocks are similar.
How long ago do scientists think the solar system formed?(1 point)
Responses
2.6 billion years ago
2.6 billion years ago
6.2 billion years ago
6.2 billion years ago
4.6 billion years ago
4.6 billion years ago
4.3 million years ago
4.6 billion years ago
Why is deuterium oxide called “heavy water”?(1 point)
Responses
It has extra oxygen atoms.
It has extra oxygen atoms.
Its hydrogen atoms are heavier than others.
Its hydrogen atoms are heavier than others.
Its oxygen atoms are heavier than others.
Its oxygen atoms are heavier than others.
It has extra hydrogen atoms.
Its hydrogen atoms are heavier than others.
Why is it hard to find the age of Earth?(1 point)
Responses
Earth's surface is constantly changing.
Earth's surface is constantly changing.
There is no way to find the age of rocks.
There is no way to find the age of rocks.
The Earth is constantly moving.
The Earth is constantly moving.
There are too many layers of Earth.
Earth's surface is constantly changing.
The correct answer is: the radioactive decay of uranium to lead.
To determine the age of the Earth, scientists use a method called radiometric dating. One type of radiometric dating is based on the radioactive decay of uranium isotopes. Uranium naturally occurs in the Earth's crust, and it has a long half-life, which means it takes a significant amount of time for half of the uranium atoms to decay into lead.
By measuring the ratio of uranium to lead isotopes in rocks or minerals, scientists can calculate how much time has passed since the rock or mineral crystallized. This allows them to determine the age of the Earth and other geological materials.
Other answer choices such as the chemical reactivity of zircon ions, electrical conductivity of uranium ions, or magnetic field surrounding zircon are not directly related to determining the age of the Earth. While zircon can be used in radiometric dating, it is the radioactive decay of uranium to lead that provides the key information about the Earth's age.