The Chemical sunset demonstrates the Tyndall effect in a fun and engaging way. We have used this demonstration for both instructional and outreach purposes. Colloidal sulfur is produced by the reaction between sodium thiosulfate and hydrochloric acid.
The determination of the limiting and excess reagents in a chemical reaction tends to be a challenge for many chemistry students. Teachers have used the making of cookies and hamburgers, or combinations of nuts and bolts, among other common items to help students understand these concepts. While students understand that if you have 10 hamburger patties and only 6 pickles one can only make 3 hamburgers, if each requires 2 pickles.
Penney Sconzo presented this nifty demonstration at the ChemEd 2015 Generations Symposium in Kennesaw State University, Kennesaw GA. This is an easy, colorful and safe microscale version of the Ammonia Fountain.
Vitamin C, chemically known as L-ascorbic acid, is an important nutrient that provides support to body structures, contributes to wound healing and aids the immune system in preventing infection. In this activity, participants learn how to determine whether vitamin C is present in commercial drinks and, if so, how to measure the relative amount.
On its own, hydrogen peroxide slowly decomposes into oxygen and water. For this reason, fresh bottles of drugstore hydrogen peroxide, labeled 3%, are actually 6%. This is so the hydrogen peroxide remains above 3% at the expiration date, if stored properly.
The catalytic oxidation of tartrate ions by hydrogen peroxide has been a staple of the Duke chemistry instructional program for many years. The demonstration clearly and colorfully brings to life the textbook description of what a catalyst is and how it enables a reaction to proceed at a faster rate by becoming involved in the reaction, yet in the end returns to its original state.
Most everyone, young and old, enjoys consuming gummy bears. They are chewy, juicy and sugary sweet! And speaking of sugar, each and every gummy bear is packed full of energy. Just how much can be qualitatively demonstrated by “The Exploding Gummy Bear” as titled by Sonia, or more accurately by “The Rapid Oxidation of Sugar.”
Demonstrating the magnetic ink used in printing US currency has proven to engage audiences of all ages because of its relevance to everyday life. Nearly everyone has used machines that distribute and/or accept currency but few understand how the machines distinguish between the various denominations. The key is in the face of each denomination.
Oobleck, a mixture of cornstarch and water, derives its name from the story “Bartholomew and the Oobleck” by Dr. Seuss (Random House), in which the king, tired of the rain, snow, and sleet falling from the sky, wishes for something different. Soon his wish is granted; green, sticky, gooey oobleck falls making a mess of his kingdom, leading the king to regret his wish. Bartholomew saves the day by getting the king to say the magic words, “I’m sorry.”
Propane Bubbles continues to be one of our most popular demonstrations among audiences and presenters alike. Propane-filled soap bubbles are generated, released into the air, and then ignited.