Demystifying the Poly Density Bottle


Dr. Kenneth Lyle, Duke University Department of Chemistryby Dr. Kenneth Lyle

The demonstration

The Poly Density Bottle is a fascinating demonstration primarily due to the phenomena being counterintuitive to what one would expect.  The bottle containing white and blue beads suspended in a clear and colorless liquid is shaken vigorously, distributing the beads randomly throughout (bottle A).  Upon standing, the beads separate from one another (bottle B) with the white rising to the surface while the blue sink to the bottom (bottle C).  Then, the two sets of beads move towards one another (bottle D) meeting near the middle (bottle E).  This demonstration can be easily repeated again and again.  And, once prepared, it can be stored for subsequent use year after year.  No additional preparation is required. Read the rest of this entry »


The “Magic” of the Soother Ooze Tube


KenByrneBy Ken Byrne

Someone once told me that all magic is science, and all science is magic.  To me, a magic show is a series of puzzles for me to solve, trying to figure out just how they pulled off an illusion.  My favorite science demonstrations are much the same.  I love those demonstrations that make me scratch my head and ask, “Why?”

Here is one of my favorites that is easy and inexpensive.  It feels like a magic trick, but it is all science.  It simply involves rolling a cylinder down an inclined plane.  Sometimes the cylinder will roll down quickly.  Other times it will crawl down slowly. Read the rest of this entry »


Discrepant Event Science in the Classroom


Discrepant Event Science! - Educational Innovations BlogBack to School with Discrepant Event Science!

by Mike Matthews

After a restful summer (which included a move to a new school!), classes are finally back in session! I always begin the year with a set of activities that challenge students to practice science process skills (observing, recording data, asking questions, etc.). My approach includes a series of quick “discrepant event” demos that captivate (and baffle) my students. From trying to figure out why two ice cubes melt at dramatically different rates to brainstorming explanations for how a sealed opaque balloon suddenly starts self-inflating, these demos engage students, assess their science skills, and emphasize the processes and habits that scientists use to inquire about the world around them.

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You Said It! Density Product Reviews


Educational Innovations Newsletter - You Said ItWhenever we attend a science convention, we bring plenty of density demos.  They are invariably among our best showstoppers!  There is something wonderfully confounding—and compelling—about watching a (seemingly) heavy object float against our expectations, or seeing (seemingly) identical beads travel in separate directions.  This curiosity is the heart of why discrepant events are so valuable to educators.

Is it magic?  No, it’s density!

Is your favorite Educational Innovations‘ density product on this list?  If not, write to us in the comments below and let us know what we forgot!

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Density Lesson


Lesson Ideas | Educational Innovations, Inc.There are so many great density lessons to choose from, we couldn’t decide!  So we’re offering two lessons here—both of them easy to implement in your classroom and sure to spark a discussion on why things sink (or float).  Density, here we come!

Click on the image below for a full-size, printable PDF.  Enjoy!

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