Universe Cycle - Solar System (1)
Pre Lab 

  • Differentiating between a star and a planet.
  • Exploring our Solar System.
  • Earth
  • planet
  • Solar System
  • Sun
  • Universe

Students learn about the different planets.


Our Solar System has a central Sun, around which revolve the nine planets and countless small objects. As a unit the Solar System revolves amongst the stars of the Milky Way, slowly circling the core of the galaxy.

There are numerous differences between the Sun and the planets. These include:

  1. radiation vs. reflection - The Sun creates its own energy; we see this energy radiating as light. The planets only reflect the light created by the sun
  2. size - The Sun is by far the largest body in the Solar System, with a diameter of 1.4 x 1016 kilometers - that is 14 followed by fifteen zeros! Jupiter is the largest planet, with a diameter of 142980 kilometers. The Earth’s diameter is 12756 kilometers.
  3. composition - the Sun is largely composed of gaseous hydrogen and helium, with small amounts of other elements. The planets have a wide variety of compositions. Jupiter , Saturn, Uranus, and Neptune are similar to the Sun, but contain more carbon compounds such as methane, and small amounts of rock. The inner planets - Mars, Earth, Venus, and Mercury, are composed mostly of rock and metal, with thin gaseous atmospheres. The composition of Pluto is uncertain.
  4. temperature - the Sun is very hot; its surface temperature is about 6000 K (degrees Kelvin). The planets are much cooler. Venus has the hottest planetary surface temperature, about 750K, while Pluto likely has the coldest, at about 50 K.
  1. Explain to the students that our Sun and its planets are called the Solar System. Tell them that the Solar System is part of a larger grouping of stars, called a galaxy. Our galaxy is called the Milky Way; this is where the name of the candy bar came from. Emphasize to the students that the Solar System and the Milky Way are only a small part of the Universe. Go over the different planets of the Solar System. Draw a picture as below to show the planets orbit. Notice that the planets revolve around the Sun in a well defined zone. The planets do not revolve in any direction.

  1. Use the Planetarium to show students the movement of the Earth and Sun. The Sun also shows how it generates light. Only stars produce light; all other bodies in the Universe only reflect starlight.
  2. Have the students complete the worksheet. First, have them list the differences between a star and a planet. You can have them work individually, or go over the answers as a group.

    Next, have the students color the worksheet, using colors which accurately portray the Sun and Earth. The Sun can be yellow to orange. The Earth can be white (clouds), blue (ocean), and brown or green (continents).

  3. Read the book Is there Life in Outer Space to the class. This will familiarize the students with the different components of the Solar System. Do not have them memorize information about the planets. Instead, let them slowly digest the information.

    Information on the planets increases every year. Not only is the United States exploring space, but many other countries are investigating the planets of our Solar System. Books that have been published in the past may contain erroneous or out-of-date information because of this new research. However, these books may still be useful for their ability to reach younger children, as long as you correct their mistakes.

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