Mixing Light Colors with the Three Port Light Source


Marty SagendorfBy: Martin Sagendorf

We see hundreds of colors, but the colors we think we see are often not what we’re actually seeing – i.e. many of these colors are combinations of other colors.  ‘Light’s Story’ is fascinating and full of surprises.  It begins with knowing that radiating and re-radiating substances emit light.  The light colors emitted are functions of a number of factors: the substance, or the incident light, or the temperature of an incandescent source.

All the textbooks explain ‘additive’ and ‘subtractive’ colors.  Explanations are fine, but actual experience makes both an immediate impression and a very lasting learning experience.  For example, here’s how only RED, GREEN, and BLUE light colors combine to produce two new unexpected colors.

Mixing Light - Educational Innovations

But we’re getting ahead of ourselves… let’s start with something we’re really familiar with: pigment colors.  We all know that mixing different paint (pigment) colors will produce new colors.  For example, when we mix red and green pigments we ‘see’ brown. And, as everyone knows, mixing a wide range of pigment colors will produce the ‘color’ we see as black.  But, odd things happen when we mix two light colors.  We don’t get the same color that we obtained when we mixed pigments.

When we mix red and green light colors we don’t ‘see’ brown: we see yellow!  How can this be?  Then… even though it does appear even more counter-intuitive, the mixing of all light colors produces the color we ‘see’ as white (but has NO color? – white… or does it?). Read the rest of this entry »


Density of Gasses


Tami O'Connor, Educational Innovationsby:  Tami O’Connor

Why do some objects float while others sink?  Archimedes discovered that an object is buoyed upward with a force equal to the weight of the fluid displaced.  An object will float in a fluid whenever its weight is less than the weight of the fluid displaced; otherwise it will sink…  So what does this mean in English??? An easier way to think about it is that an object that is less dense than the fluid it is in will rise to the top of the more dense fluid.

In demonstrations of liquids of varying densities, the liquid with the greatest density will sink to the bottom of the container while the less dense liquid will remain on the top.  There are wonderful demonstrations you can conduct with your class using immiscible liquids (liquids that do not mix) of different densities, and there are a number of high interest experiments your students can conduct using liquids of different densities.  If you find this topic interesting, please visit the blog we wrote on the W-Tube.

Demystifying the Poly Density Bottle-Educational Innovations Blog

Gasses also have varying densities, but in the elementary and middle school classrooms, students don’t often have the same opportunity to work with gasses as they would liquids, or more often, liquids and solids. Read the rest of this entry »


Bring Some Magic Into Your Classroom!


Ted Beyer, Educational Innovationsby Ted Beyer

One of my favorite authors, Arthur C. Clark, once said, “Any sufficiently advanced technology is indistinguishable from magic.” This has been quoted, misquoted and reused for years.  Of course, it’s perfectly true, and magicians have been using science as part of their acts for centuries. Things that we take for granted today were once bleeding edge technology. I remember in high school reading that sometime ‘soon’ (this was more than 30 years ago) there would be TVs that would be so thin that they would hang on the wall like pictures – impossible! A generation before, the concept of television itself was astonishing, and a generation before that, moving pictures of any kind were magical.

As I started to think about this, I suddenly realized that there are many products that we sell here at Educational Innovations that are used – currently – by magicians as ‘tricks’ in their act. Let’s take a look…. Read the rest of this entry »


Great Balls and Fire! Smashing Steel Spheres with Video


Tami O'Connor, Educational Innovationsby:  Tami O’Connor

When two 1-pound, 2-inch diameter, chrome steel spheres are smashed together, enough heat is generated at the point of contact to burn a hole in ordinary paper!  This dramatic demonstration has been a favorite of students in every grade for as long as I have been teaching!

Smashing Steel Sphere Demo KitThere are a few considerations when allowing students (especially younger ones) to conduct this activity on their own…  First, the spheres are pretty heavy, so if they were either dropped on a foot or onto a nice tile floor, the result would not be good.  Also, be sure that the only thing between the spheres is paper or aluminum foil.  Fingers caught between the colliding spheres would not  be happy.  Finally, all participants should wear safety glasses, as it is not unusual for a small piece of paper to fly off after the spheres collide.

Read the rest of this entry »


Seeing a 3D Magnetic Field


Marty Sagendorfby: Martin Sagendorf

This 3D Magnetic Field demonstration is actually quite easy to do.  It clearly illustrates that magnetic fields are not flat (as too frequently demonstrated in the classroom).

Demonstrating a 3D Magnetic Field

This easy-to-make construction requires only four components:

  1. A clear plastic bottle (about 1-3/4” in one dimension) – the one illustrated below is a 12.6 fl oz ultra concentrated Joy ® dishwashing soap bottle – Note that any bottle originally containing soap or detergent will require repeated rinses to completely remove all of its original contents.

    Seeing a 3D Magnetic Field | Educational Innovations

  2. Six 17 mm x 3 mm Neodymium ring magnets Read the rest of this entry »