Demonstrations

Introduction

In this demonstration sodium hydroxide, dry ice and an indicator are used to create a cylinder full of colorful, bubbling liquid.

A two-liter graduated cylinder is prepared, and filled with roughly 1.5 liters of water. Next, sodium hydroxide, a strong base, is added. Along with this a universal indicator is added, which shows several color changes to allow you to estimate the pH of the solution at all points. Then dry ice, or solid carbon dioxide is added, which becomes a gas and reacts with the water to become carbonic acid, which acidifies the solution. Along with bubbling nicely, the cylinder slowly changes colors because of the indicator. See a detailed explanation.

Introduction

In this demonstration we use distilled water and liquid nitrogen to create a small explosion.

A small iron flask is filled to the brim with distilled water and then screwed shut. Care is taken to ensure no air remains trapped inside the flask as this can ruin the demonstration. After it is tightly shut, the bomb is submerged into liquid nitrogen. The use of liquid nitrogen is not required, only a source of cold sufficient to freeze the ice, but liquid nitrogen is a quick and efficient method to provide this during a road show. The ice then begins to freeze, and expand. This increase in the size of the materials on the inside creates vast amounts of pressure, which is eventually enough to cause the iron casing to explode. The small explosion this creates launches liquid nitrogen into the air, which mostly becomes a gas because of the heat of the air, thus causing most of the visuals of the small explosion. See a detailed explanation.

Introduction

This demonstration produces a large eruption of colorful foam that appears to be elephant toothpaste.

Summary

Hydrogen peroxide, dish liquid, and food coloring are placed into a large, glass graduated cylinder. Hydrogen Peroxide decomposes into liquid water and oxygen gas, but this reaction proceeds so slowly that we need a catalyst to speed up the reaction. This is the role of potassium iodide; it speeds up the reaction, but is not consumed. This addition of potassium iodide causes the large eruption of foam because adding the catalysts to the hydrogen peroxide quickly produces the oxygen gas, but the liquid soap catches the oxygen to produce our foamy toothpaste! See a detailed explanation.

Introduction

In this demonstration a liquid solution will repeatedly change color from clear, to yellow, to blue, then back to clear

Summary

Elemental iodine which, when inhaled, can cause respiratory distress, is used in this demonstration. You must wear gloves and safety glasses, and perform the demonstration in a well-ventilated area, preferably under a chemical hood.

Potassium Iodate, Malonic Acid and Hydrogen Peroxide are mixed in a flask agitaged by a stirrer plate. Essentially, three separate chemical reactions are occurring, but the products of the first reaction are the reactants of the second reaction. The products of the second reaction are the reactants of the third reaction, and the products of the third reaction are the reactants of the first reaction, thus restarting the entire cycle. The reactions will repeatedly produce color changes from clear, to yellow, to blue, then back to clear for about 5 minutes, then eventually become a dark blue permanently. See a detailed explanation.

Introduction

In this demonstration we appear to be burning money.

Summary

A dollar bill is soaked in a 50/50 solution of isopropyl alcohol and water, then ignited and extinguished. The flame burns the alcohol and boils off some water leaving a slightly damp dollar bill. See a detailed explanation.

Introduction

This demonstration turns what appears to be nothing in six beakers, into the the six primary colors of the rainbow.

Summary

Indicators are mixed with acid and placed in six beakers. A pitcher is filled with a base which, when added to the beakers, begins to neutralize the acid. Once enough base is added the indicators will show their colors. Next, a small beaker of acid is added to the pitcher. Then, all the beakers are added back to the pitcher and the solution will be acidic enough as to keep the indicators from showing. See a detailed explanation.