The Floating Golf Ball
An activity from Kim Giesting (Connersville, IN)
Type of Lesson: Experiment/Discussion
Time Needed: 40 minutes
MEGOSE PME17 Describe and compare objects in terms of mass, volume, and density.
Quick Summary of Lesson
This activity is an intro to a discussion on density.
clear plastic container
kosher (pickling) salt, salt
1. Fill container 1/2 full of tap water.
2. Add salt until no more salt dissolves.
3. Add golf ball to the salt solution (it should float!).
4. Gently add fresh water on top of the salt water solution.
Notes to the Teacher
I use this activity as a "teaser" to our discussion on density. I have it set up when the students arrive in class. Without any explanation, I give the students all of the materials and have them try and make their own golf balls float halfway in a container of water. Eventually, all student groups are successful. After they are successful, we have a discussion about density and why the golf balls are floating at that particular location. Many students mistakenly believe that they are diluting the solution of salt water to the "perfect" concentration when adding the fresh water. I add a few drops of food coloring and gently stir to show them that the fresh water is less dense and is actually sitting on top of the more dense salt water. The golf ball is actually floating on the salt water and sinking through the fresh water.
Need More Information? Try Using Windows to the Universe
Please use these links for further ideas or more information:
Density of the Earth
Density inside the Sun
Energy density inside tornadoes
Another activity for the classroom called Diving Raisins
Last modified prior to September, 2000 by the Windows Team
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