Praxis Elementary Education Exam—Our Solar System

By Carla C. Kirkland, Chan Cleveland

On the Praxis Elementary Education exam, you may be asked questions about Earth and the other planets and objects in our solar system. You should also be familiar with how Earth revolves around the sun, and how the moon rotates around Earth.

A year is the time it takes Earth to make one revolution around the sun. A month (the lunar month = 28 days) is the time it takes the moon to make a revolution around Earth.

As Earth revolves, it rotates on an axis, resulting in day and night. The moon also rotates on an axis, and it does so at the same rate of speed as Earth’s rotation. As a consequence, we only ever see one side of the moon as it’s lit by the sun, resulting in the portion of the moon—or phase—we see.

Eclipses happen when either the Earth blocks sunlight from reaching the moon, and it is eclipsed (lunar), or when the moon blocks sunlight from reaching the Earth, and the sun is eclipsed (solar).

Earth and its moon are part of our solar system, which includes eight planets and one dwarf planet, Pluto. Mercury, Venus, Earth, and Mars—the inner planets—are made mostly of rock and are the smaller group of planets. The larger group—Jupiter, Saturn, Uranus, and Neptune—all have rings and are made mostly of gas; they’re often referred to as the gas giants. Also found in our solar system are the following:

  • Asteroids. Large, rock-like objects orbiting the sun; the Asteroid Belt lies between Mars and Jupiter
  • Meteoroids. Small, rock-like objects (smaller than 10 meters in diameter) orbiting the sun
  • Meteorites. What’s left of a meteoroid that has burned in the atmosphere and fallen to Earth
  • Comets. Bodies also orbiting the sun and made of a nucleus surrounded by dust and gas that often forms a tail

Practice question

  1. Which explains the main cause of a solar eclipse?
    A. the Big Bang theory
    B. the casting of a shadow
    C. the lunar revolution
    D. the tilt of the Earth’s axis

Answer and explanation

  1. The correct answer is Choice (B).
    During a solar eclipse, the moon blocks sunlight from, or casts a shadow on, the Earth. Choice (A) is an explanation for how the universe was created, more of an ongoing expansion than an actual explosion. Choice (C) is the 28-day period it takes the moon to make one revolution around the Earth. Choice (D) is the main cause of the seasons.