Unit Planet Review

Learning Objectives

SCI.4.5.1 Explain that all planets rotate on their axes and revolve around the
sun, and explain the differences between the Earth’s rotation and revolution.
(SOL 4.5a)

SCI.4.5.2 Identify the relative location of the planets in relation to the sun and
classify them as either terrestrial or a gas giant. (SOL 4.5b)

SCI.4.5.3 Compare the relative sizes of the planets to each other as well as
to the sun. (SOL 4.5c)

Sun

All of the planets revolve around the Sun and rotate around their
own axes.

The rate at which they rotate determines the length of the
planet’s day and the amount of time it takes for the planet to
revolve determines the length of its year.

Each of the planets is distinct in its characteristics

In order from the Sun: Mercury, Venus, Earth, Mars, Jupiter,
Saturn, Uranus, and Neptune.

Jupiter is the largest, and Mercury is the smallest

The four inner planets are called terrestrial planets due to their
rocky composition

The four outer planets are known as the gas giants

The Planets

Earth/Sun Interactions

Two popular theories emerged to describe Earth’s relationship to the Sun and other planets
in the solar system.

➔

Geocentric theory: the moon, sun, planets and stars all circled the Earth in spheres.
This theory places Earth in the center of our solar system.

➔

Heliocentric theory: the sun in the center of our solar system, with the Earth and the
other planets circling the sun.

Earth/Sun Interactions

Earth rotates around its own axis and therefore, part of Earth is in
shadow while the other half is not. This is the cause of day and
night (24 hours)

Earth also revolves in an orbit around the sun. One revolution
equals one Earth year (365 days)