5th Grade Science Unit 2 Study Guide

Planets that are made of rocks, minerals, and metals are called

• Gas Giants

• Terrestrial Planets

• Exoplanets

• Ice Giants

Answer explanation

Planets that are made of rocks, minerals, and metals are called Terrestrial Planets, which distinguishes them from Gas Giants, Exoplanets, and Ice Giants.

Which of the following primarily make up comets? Select the two correct answers.

• Ice

• Gas

• Metal

• Carbon dioxide

Answer explanation

Comets are primarily made up of ice and gas, not metal or carbon dioxide. These elements form the core components of comets.

What makes Uranus unique as a planet?

• It rotates sideways due to the extreme tilt of its axis.

• It has no day and night cycle.

• It spins in the opposite direction as the Earth.

• It has the slowest rotation period of any planet.

Answer explanation

Uranus rotates sideways due to the extreme tilt of its axis, making it unique among planets.

If the diameters of all the planets in our solar system are added together, would the sum be greater than or less than the diameter of the sun? What does this tell you about the size of the sun?

• Greater than; the sun is smaller than the combined size of all the planets.

• Less than; the sun is larger than the combined size of all the planets.

• Equal to; the sun is the same size as the combined size of all the planets.

• Cannot be determined; there is not enough information.

Answer explanation

Less than; the sun is larger than the combined size of all the planets.

Which statement describes what it means for a planet’s orbit to be elliptical?

• The planet’s path around the sun is not a perfect circle and is shaped like an oval.

• The planet’s axis is tilted.

• The planet’s axis is not tilted and is oriented vertically.

• The planet’s path around the sun is shaped like a perfect circle.

Answer explanation

The planet’s orbit being elliptical means its path around the sun is not a perfect circle and is shaped like an oval.

Which list shows the planets in the correct order from smallest to largest diameter?

• Mercury, Mars, Venus, Earth

• Mars, Mercury, Venus, Earth

• Venus, Mercury, Mars, Earth

• Earth, Venus, Mars, Mercury

Answer explanation

The correct order from smallest to largest diameter is Mercury, Mars, Venus, Earth, which matches the first option.

Why does a comet make a bright trail in the night sky?

• A comet is made of rock, which burns and lights up as the comet moves faster in the atmosphere.

• A comet is made of ice, dust and gas that vaporize as the comet moves closer to the sun, leaving a trail.

• A comet gives off light because of the mineral composition of the rocks from which the comet is formed.

• A comet produces an optical illusion of a bright trail due to the layers of Earth's atmosphere.

Answer explanation

A comet is made of ice, dust and gas that vaporize as the comet moves closer to the sun, leaving a trail.

Which of the following lists the planets in the correct order from closest to farthest from the Sun?

• Mars, Mercury, Earth, Venus, Neptune, Saturn, Uranus, Jupiter

• Venus, Mercury, Earth, Mars, Neptune, Uranus, Saturn, Jupiter

• Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter

• Mercury, Mars, Venus, Earth, Uranus, Neptune, Saturn, Jupiter

Answer explanation

The correct order of planets from closest to farthest from the Sun is Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter.

Suppose you use a ball placed near a lamp to model day and night on Earth. You place a pencil through the ball and tilt it slightly to represent Earth’s axis. How should you spin the globe to model the rising and setting of the sun?

• Spin the globe from left to right so the sun will appear to move from east to west in the sky.

• Spin the globe from right to left so the sun will appear to move from east to west in the sky.

• Spin the globe from left to right so the sun will appear to move from west to east in the sky.

• Spin the globe from right to left so the sun will appear to move from west to east in the sky.

Answer explanation

Spin the globe from left to right so the sun will appear to move from east to west in the sky.

Imagine modeling Earth’s rotation using a foam ball with a lamp nearby. You draw an X on the ball at the spot closest to the lamp, and then you slowly rotate the ball. How far should you rotate the ball so that X is at a spot representing 6:00 p.m.?

• 1 full rotation

• ¼ of a rotation

• ¾ of a rotation

• ½ of a rotation

Answer explanation

To have X at 6:00 p.m., you need to rotate the ball halfway, which represents half a rotation.