The use of dynamic audio-visual aids in the classroom has become widely accepted. Personal computers connected to small video projectors are now commonly used in Middle School science classrooms to present videos and oral presentations. Brief descriptions of some of the presentations that RESEED volunteers and their teacher partners use appear on this page. These A-V presentations are available to volunteers and web site guests in Microsoft PowerPoint® file format. Send an e-mail to drjcast@aol.com using the keyword(s) shown below for the specific presentation(s) you would like to view in the subject line of the e-mail.
The Structure of Simple Carbohydrates
This lesson describes the nature carbohydrates and teaches students the difference between molecular formulas and structural formulas. Keyword: Carbohydrates
Glue Ball Chemistry
The nature and structure of polymers are discussed in this presentation. In addition, the students are instructed to perform a simple experiment that enables them to convert a small amount of Elmer’s glue to a rubber ball using the concept of polymer “cross-linking.” Keywords: Glue Ball
Physical and Chemical Changes
The differences between physical and chemical changes as well as the clues to a chemical reaction are described in this presentation. It is used as a prelude to the demonstration of “Halloween Colors,” the reaction between hydrogen peroxide and potassium dichromate, which involves multiple chemical reactions occurring at different rates. Keywords: Halloween Colors
Laws of Conservation of Mass and Definite Proportions
The two laws are defined and the reaction between sodium bicarbonate and acetic acid is analyzed in detail. The presentation is used prior to a demonstration with a rigid bottle containing the reactants on a triple beam balance. The calculations are shown to prove that the mass of the products of a chemical reaction are equal to the mass of the reactants, and that the law of definite proportions is followed. Keyword: Conservation
The Difference between Mass and Weight
This short lesson explains the difference between mass and weight and their connection. Keyword: Mass-Weight
The Measurement of pH
The definition of pH, how the scale is made, and the techniques used to measure it are described. This presentation is intended to be used in conjunction with the activity where students prepare dilute solutions of orange juice and measure their pH. Keywords: Measuring pH
Origin of the Elements
Theories of how the universe was formed and the origin of the elements are described. Starting with hydrogen, the lesson shows how the elements were created by nuclear fusion in stars, novas, and supernovas. Keyword: Origin
Oscillating Chemical Reaction
This presentation includes a video that shows the Briggs-Rauscher reaction, a rare example of an oscillating chemical reaction that produces alternating changes in color over many cycles. The discoverers of the reaction are high school teachers, so the chemistry described in the presentation is aimed at advanced Middle School students. Keywords: Oscillating Reaction
Self Darkening Sunglasses
An example of a reversible chemical reaction used in glasses that darken in sunlight and become clear in ordinary room is briefly described. The concept is known as “photochromism” and the presentation shows how the molecule’s structure changes from one form to another in light and dark. Keywords: Photochromic Glasses
The Scientific Method
Intended for presentation early in the first semester of Middle School physical science, this talk covers the definition of science, discusses how scientists work, and outlines the steps involved in the scientific method. There is also a discussion of measurements and the importance of science in today's world. Keywords: Science Methods
The Dehydration of Sucrose
This short presentation is given prior to the demonstration of the acid-catalyzed decomposition of common table sugar (sucrose). The mechanism of the dehydration reaction that occurs is shown by the use of structural formulas. Keywords: Sucrose Dehydration
The Meaning and Use of Pi
A short presentation of how the constant pi was derived and how it is used. Keywords: Meaning of Pi
