Earth's Motions: Rotation and Revolution Flashcards

A set of flashcards covering Earth's rotation, revolution, day and night cycles, solar apparent motion, and moon phases based on the lecture transcript.

What is Earth's axis?

An imaginary line that runs through the Earth from the North Pole to the South Pole.

At what speed does the Earth spin on its axis?

The Earth spins at a rate of $1,070\text{ miles per hour}$.

How long does it take for Earth to make one complete turn on its axis?

It takes $24\text{ hours}$ (specifically $23\text{ hours and } 56\text{ minutes}$), which is called a day.

In what direction and pattern does the Earth rotate on its axis?

The Earth rotates from west to east, in a counterclockwise direction.

What process causes day and night on Earth as illustrated in this diagram?

The rotation of Earth on its axis, where the half facing the sun has daytime and the half facing away from the sun has nighttime.

What is the horizon?

The line where the sky and the Earth's surface seem to meet.

According to this diagram, what path does the sun appear to take across the sky during the day?

The sun appears to rise in the east at sunrise, move higher until reaching its highest point at midday or noon, move lower in the afternoon, and set in the west at sunset.

Why do the sun, moon, and stars appear to move across our sky?

They only appear to move across the sky because the Earth is rotating on its axis.

What is revolution in the context of Earth's motion?

Earth moving in an elliptical path, or orbit, around the sun.

How long does it take for Earth to complete one full revolution around the sun?

It takes $365\frac{1}{4}\text{ days}$ (known as one year).

What causes the extra day added to February during a Leap Year?

The extra $\frac{1}{4}\text{ days}$ from Earth's $365\frac{1}{4}\text{ day}$ annual revolution add up over four years to form one full extra day.

What movements are depicted in this diagram regarding the Earth, Sun, and Moon?

The Earth revolving in an elliptical path around the Sun (taking $365\frac{1}{4}\text{ days}$) and the Moon revolving around the Earth (taking about one month).

How long does it take for the Moon to make one complete revolution around the Earth?

About one month.

What is a phase of the moon?

One of the shapes of the lit half of the moon as seen from Earth.

What causes the changing phases of the moon?

The moon's revolution around the Earth, which changes how much of the sunlit half of the moon can be seen from Earth.