Chemical Reactions Demonstrations

Chemical reactions transform substances into new materials with different properties. They’re central to understanding change in the material world, and there are many possible demonstrations. Because this category is so broad, only a selection of demos is included here.

Demonstration	Materials	Difficulty	Safety	Summary
Elephant's Toothpaste	★★☆	★★☆	★★☆	30% hydrogen peroxide is added to a potassium iodide catalyst, detergent and food colouring, and oxygen bubbles rapidly produce a foam.
Baking Soda and Vinegar Volcano	★☆☆	★☆☆	★☆☆	A cone-shaped volcano model is built around a bottle. A mixture of bicarbonate of soda, water, and washing-up liquid is placed inside, and vinegar with food coloring is added to create a foamy eruption that resembles lava flow.
Carbon Sugar Snake	★★★	★★☆	★★★	A mixture of sugar and baking soda is ignited with lighter fluid on a sand base, producing an expanding black "snake" of carbon and sodium carbonate as gases from decomposition push the solid upward.
Sodium in Water	★★★	★★★	★★★	A pea-sized piece of sodium metal is placed on water, where it reacts exothermically to form sodium hydroxide and hydrogen gas. Heat from the reaction can ignite the hydrogen, and a pH indicator shows the solution becoming alkaline.
Ammonium Dichromate Volcano	★★★	★★☆	★★★	A small mound of ammonium dichromate is ignited so it decomposes with sparks and a dramatic color change from bright orange crystals to dark green chromium(III) oxide, resembling a miniature volcano.
Burning Magnesium Ribbon	★★☆	★★☆	★★☆	A strip of magnesium ribbon, when ignited, burns with an intense white flame, producing magnesium oxide. The reaction is highly exothermic and demonstrates how metals can react vigorously with oxygen.
Dichromate Breathalyzer	★★☆	★★☆	★★☆	An orange chromic acid (or Acidified Dichromate) reagent is added to two cylinders, one with water and one with ethanol. The water sample stays orange, while ethanol is oxidized to acetic acid and the chromium(VI) reagent is reduced to green chromium(III).
Carbon Dioxide Fire Extinguisher	★☆☆	★☆☆	★☆☆	Baking soda and vinegar react to produce carbon dioxide gas, which is then poured over lit candles to extinguish the flames. This models how fire extinguishers use gases to smother fire.
Making Soap	★★☆	★★☆	★★☆	Coconut oil is combined with sodium hydroxide to undergo saponification and produce soap. The crude soap is then purified through salt precipitation to lower its pH and remove impurities, resulting in a safe and usable bar of soap.
Sugar and Sulfuric Acid Carbon Snake	★★☆	★★☆	★★☆	Concentrated sulfuric acid is added to sugar, causing a vigorous dehydration and oxidation reaction. The mixture heats up and produces steam, carbon dioxide, and a growing black column of carbon that resembles a snake rising from the container.
Glow Sticks at Different Temperatures	★☆☆	★☆☆	★★☆	Glow sticks glow due to chemiluminescence, a chemical reaction that releases light. Cold slows the reaction, producing a dimmer glow, while heat speeds it up, making the glow brighter but shorter-lived.
Disappearing X Reaction	★★☆	★★☆	★★☆	Hydrochloric acid reacts with sodium thiosulfate to produce sulfur, sulfur dioxide, and sodium chloride. As sulfur forms, the solution becomes cloudy. The time taken for a marked “X” beneath the beaker to disappear is used to measure reaction rate at different concentrations of sodium thiosulfate, allowing the order of the reaction to be determined.
Cannon Fire Reaction	★★☆	★★☆	★★★	Hydrogen peroxide reacts with potassium permanganate to generate bursts of oxygen that make a burning ethanol mixture crack, pop, and roar like cannon fire; adding a metal salt can color the flame.
Snowstorm in a Jar	★★☆	★☆☆	★☆☆	Layer a water–paint mixture beneath baby oil and start an acid–base reaction with pieces of effervescent tablet. Carbon dioxide bubbles lift painty water droplets up through the oil; when bubbles burst, the droplets fall like snow.
Golden Rain	★★☆	★★☆	★★☆	Lead nitrate reacts with potassium iodide to form a bright yellow precipitate of lead iodide. When heated, the precipitate dissolves in hot water, but as the solution cools, thin hexagonal crystals fall out of solution like golden flakes, creating the “golden rain” effect.
Lemon Juice Invisible Ink	★☆☆	★☆☆	★★☆	Lemon juice is used to write a hidden message that becomes visible when heated with an iron.
Milk of Magnesia Changing Colors	★★☆	★★☆	★★☆	Milk of magnesia, a suspension of magnesium hydroxide, is mixed with a universal indicator to show its alkaline nature. When vinegar is added, the solution rapidly shifts through the color spectrum as the acid reacts with the base, demonstrating how antacids neutralize stomach acid.
Oscillating Clock Reaction	★★★	★★☆	★★☆	The Briggs-Rauscher reaction is a dramatic oscillating chemical reaction in which a solution alternates between amber and blue-black colors several times before settling into a final dark-blue state. The color changes are caused by the interplay of iodine species, hydrogen peroxide, malonic acid, starch, and a manganese catalyst.
Thermite	★★☆	★★☆	★★★	The thermite reaction produces molten iron by reducing iron(III) oxide with aluminum powder. Once ignited, the highly exothermic reaction releases intense heat and light, creating a dramatic classroom demonstration of redox chemistry.
Glowstick Dissection	★★☆	★★☆	★★★	This demonstration explores the chemical reaction inside glowsticks by dissecting them and using their contents to create glowing artwork. Students learn about chemiluminescence and reaction rates while experimenting with color, brightness, and duration of glow.
Water Into Wine	★★☆	★☆☆	★☆☆	This demonstration uses the pH indicator phenolphthalein and sodium carbonate to make water appear to turn into wine or blood. The liquid changes from colorless to pink or red under basic conditions, and can be reversed to clear again by adding acid or blowing carbon dioxide into the solution.
Water to Wine to Milk to Beer	★★☆	★★☆	★★★	This dramatic chemistry demonstration makes a liquid appear to transform into water, wine, milk, and beer as it is poured from one glass to another. The sequence involves pH indicators, precipitate formation, and gas release, illustrating multiple chemical concepts in a visually striking way.
Steel Wool and Vinegar Exothermic Reaction	★☆☆	★☆☆	★☆☆	This experiment shows how rusting, a type of oxidation reaction, can release heat. When steel wool is soaked in vinegar, its protective coating is removed, allowing the iron to react more readily with oxygen. The oxidation produces heat, making this an example of an exothermic reaction.
Conservation of Mass with Baking Soda and Vinegar	★★☆	★☆☆	★☆☆	This experiment shows that matter is not created or destroyed in a chemical reaction. When baking soda reacts with vinegar, carbon dioxide gas inflates a balloon, and the total mass before and after the reaction remains nearly the same.
Burning Paper with Ice	★★★	★★☆	★★★	Tissue paper (or another combustible material) is ignited using a chip of ice. The ice melts, releasing water, which reacts with sodium peroxide to produce sodium hydroxide, oxygen, and heat.
Iodine Clock	★★☆	★★☆	★★☆	Two clear solutions are mixed, and after a short delay the mixture suddenly turns deep blue. The timing of the color change depends on concentration and temperature, making this a classic demonstration of chemical kinetics.
Thermite Spheres	★★★	★★☆	★★☆	Two rusty iron spheres wrapped in aluminum foil are struck together to initiate a redox reaction. The reaction releases energy in the form of a popping noise and sparks, demonstrating the principles of thermite chemistry in a controlled and safe way.
Candle and Water Rising	★☆☆	★☆☆	★★☆	When a burning candle is covered with an inverted container standing in water, the candle eventually goes out and the water rises inside the container.
Naked Egg (Bouncy Egg)	★☆☆	★☆☆	★☆☆	When an egg is placed in vinegar, the acid reacts with the calcium carbonate of the eggshell, producing carbon dioxide bubbles and dissolving the shell. What remains is a soft, rubbery membrane that can stretch and even bounce.
Lead Iodide Precipitation	★★☆	★☆☆	★★☆	When aqueous lead(II) nitrate reacts with aqueous potassium iodide, a double displacement reaction occurs. Potassium nitrate remains dissolved, while lead(II) iodide precipitates as a bright yellow solid.
Blowing Up a Balloon with Baking Soda and Vinegar	★☆☆	★☆☆	★☆☆	When baking soda inside a balloon is released into vinegar in a bottle, an acid-base reaction produces carbon dioxide gas. The gas expands and inflates the balloon without using air from your lungs.
Solid Lead Nitrate and Potassium Iodide	★★☆	★☆☆	★★☆	When lead nitrate and potassium iodide powders are combined and shaken, they undergo a double displacement reaction to produce yellow lead iodide.
Luminol Chemiluminescence	★★★	★★☆	★★☆	When luminol is mixed with hydrogen peroxide in the presence of sodium hydroxide and potassium ferricyanide, a blue glow is produced. This reaction demonstrates chemiluminescence, where chemical energy is converted directly into light energy without heat.
Genie in a Bottle	★★☆	★★☆	★★★	When manganese dioxide is added to concentrated hydrogen peroxide, it rapidly decomposes into water and oxygen gas. The escaping oxygen propels a mist of water out of the container, creating the dramatic effect of a “genie” emerging from the bottle.
Chemical Sunset	★★☆	★★☆	★★☆	When sodium thiosulfate reacts with hydrochloric acid, colloidal sulfur particles form. As the particles grow, they scatter shorter wavelengths of visible light and transmit longer wavelengths, producing a sunset-like sequence of colors when projected with an overhead projector.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff