Density is basically how tightly packed atoms are. (Mathematically, density is mass divided by volume.) For example, take a golf ball and a ping pong ball. Both are about the same size or, in other words, take up the same volume.


However, one is much heavier, has more mass, than the other. The golf ball has its atoms much more closely packed together than the ping pong ball and as such the golf ball is denser.


These are quick and easy demonstrations for density that use simple household materials:
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Density Jar

You will need to find:


  • glass jar
  • water
  • vegetable oil
  • liquid dish soap
  • honey
  • corn syrup
  • molasses
  • rubbing alcohol
  • lamp oil (optional)

Fill a clear glass partway with water. Drizzle in cooking oil. What do you see happening? Try adding in liquid dish soap (make sure it’s a different color form the water and the oil for better visibility.)


What else can you add in? What about honey, corn syrup, molasses, rubbing alcohol, or lamp oil? Use a turkey baster to help you pour the liquids in very slowly so they don’t mix. You’ll get the best results if you start with the heaviest liquids.



 
Download Student Worksheet & Exercises


Hot & Cold Swirl

To clearly illustrate how hot and cold air don’t mix, find two identical glasses.  Fill one glass to the brim with hot water.  Add a drop or two of red food coloring and watch the patterns.  Now fill the other glass to the top with very cold water and add drops of blue dye.  Do you notice a difference in how the food coloring flows?


Get a thick sheet of heavy paper (index cards work well) and use it to cap the blue glass.  Working quickly, invert the glass and stack it mouth-to-mouth with the red glass.  This is the tricky part: When the glasses are carefully lined up, remove the card.  Is it different if you invert the red glass over the blue?


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Comments

3 Responses to “Quick & Easy Density”

  1. Right, just use hot water from the sink. Don’t use boiling water.

  2. sophia_hewitt says:

    You’ll need to be careful with hot water in a glass, unless you want 2 science experiments in one!! 😀

  3. leeann_brodeur says:

    This experiment is so fun! I even added some milk.