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Kickin' Mass!

Remember that gravity pulls on all objects in the universe; you can’t hide from gravity. Mass is your resistance to change in motion. Massive things are hard to get moving and hard to stop (this is why we don’t step out in front of moving traffic.) Less massive things are easy to get moving and easy to stop, like rolling a marble. Isaac Newton taught us that the more mass you have, the larger gravitational pull you feel and vice versa.

Galileo, a famous Italian scientist who lived in the 1500s, was the first to discover the force of gravity. In his famous experiment, he dropped two cannonballs, one 10 times the mass of the other, at exactly the same time from the Leaning Tower of Pisa. With this knowledge let us pose the question, “Does mass affect gravitational pull?” Or in other words, which is pulled harder, more massive or less massive objects?

In this activity, you are going to find out which will be pulled harder by gravity, a more massive or less massive object. This activity actually works more by air resistance; however the results are the same as if you could measure the amount of gravity pulling on the different masses.



  • Eight inch Styrofoam ball
  • Four inch Styrofoam ball
  • One inch Styrofoam ball
Safety concerns: As with all science lab activities, the most important safety rule is to follow all teacher directions.


  1. In a paragraph, explain what happened as you performed this experiment and why.
  2. Does the mass of an object affect its’ gravitational pull?
  3. If you were to do this experiment in a vacuum (a place with no atmosphere like space), would your results change? Why?
  4. Look at the two sets of planets below. On the left are two massive planets and on the right are two less massive planets. Place the large arrow between the planets with the greatest gravitational pull and the small arrow between the planets with the smallest gravitational pull. Then drag your mouse over the image to check your answer.



Find a partner and time the fall to see what the actual difference is. Repeat the experiment several times and keep track of your data to see if you can come up with a pattern. Make a data table to keep your results and graph your final data.

Review Science safetey rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 8th grade science core.

Updated October 24, 2008 by: Glen Westbroek

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