In this lab, we will be studying the different physical properties of the eight* planets. We will start with an introduction to physical properties, and then move on to discuss how these properties relate to the planets.

*As of August 2006 there are only eight planets.

In August of 2006 the IAU (International Astronomical 

Union) redefined the bodies of our solar system.

A planet1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.

1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.


To learn about the properties of planets in our solar system. The main properties you will learn about are mass, density and volume. Ordering the planets according to these properties tells us a lot about how the solar system formed. You will also learn about the concepts of mass and weight (they are not the same thing).


  1. Read the background material by clicking on the topics listed on the menu on the left side of this page. For a given topic there may be multiple pages each of which can be accessed using the navigation buttons arranged across the
    top of each page.

  2. Click on the menu item "Problems". A window should open at the bottom of your screen with the questions.

  3. Read the questions carefully. Use the interactive activity that allows you to order the planets in order to answer some of the questions relating to the properties of the planets.

  4. Use the interactive module that allows you to calculate your weight on any planet to answer questions about weight and mass.

  5. Use the background material to answer all other questions.

  6. Answer the questions by filling in the form fields on the computer. Hit the button labeled "Submit" when you are done. A confirmation page will appear with all your answers imbedded. Be careful not to close the problems window until you are finished and want to submit or your answers may be lost and you will have to reenter your answers.

  7. Check over the confirmation page to make sure that you are happy with your answers. If you need to change your answers go back to step 6 and re-submit. We will only grade the last form you submit.

    Good luck!