Interesting High School Chemistry Demonstrations

High school science students can be hard to impress, but here's a list of cool and exciting chemistry demonstrations to capture student interest and illustrate chemistry concepts.

Sodium in Water Chemistry Demonstration

Sodium metal in glass bowl of red Litmus water producing sodium hydroxide and hydrogen

Getty Images / Andy Crawford and Tim Ridley 

Sodium reacts vigorously with water to form sodium hydroxide. A lot of heat/energy is released! A very small amount of sodium (or other alkali metal) produces bubbling and heat. If you have the resources and space, a larger amount in an outdoor body of water forms a memorable explosion. You can tell people the alkali metals are highly reactive, but the message is driven home by this demo.

Leidenfrost Effect Demonstrations

A water droplet experiencing Leidenfrost effect on a hot stove hot plate

Wikimedia Commons / Cryonic07

The Leidenfrost Effect occurs when a liquid droplet encounters a surface much hotter than its boiling point, producing a layer of vapor that insulates the liquid from boiling. The simplest way to demonstrate the effect is by sprinkling water on a hot pan or burner, causing the droplets to skitter away. However, there are fascinating demonstrations involving​ liquid nitrogen or molten lead.

Sulfur Hexafluoride Demonstrations

3D illustration of Sulfur hexafluoride molecular structure isolated on white

 Getty Images / ollaweila

Sulfur hexafluoride is an odorless and colorless gas. Although students know fluorine is extremely reactive and usually quite toxic, the fluorine is safely bound to sulfur in this compound, making it safe enough to handle and even to inhale. Two noteworthy chemistry demonstrations illustrate the heavy density of sulfur hexafluoride relative to air. If you pour sulfur hexafluoride into a container, you can float light objects on it, much like you would float them on water except the sulfur hexafluoride layer is completely invisible. Another demonstration produces the opposite effect from inhaling helium. If you inhale sulfur hexafluoride and speak, your voice will seem much deeper.

Burning Money Demonstration

pile of 100 dollar notes on table on fire

Getty Images / Martin Poole

Most high school chemistry demonstrations are hands-off for students, but this is one they can try at home. In this demonstration, 'paper' currency is dipped in a solution of water and alcohol and set alight. The water absorbed by the fibers of the bill protects it from ignition.

Oscillating Clock Color Changes

Causing chemical reaction by pouring red liquid from test tube into glass containing a different liquid

Getty Images / Trish Gant

The Briggs-Rauscher oscillating clock (clear-amber-blue) may be the best-known color change demo, but there are several colors of clock reactions, mostly involving acid-base reactions to produce the colors.

Supercooled Water

If you disturb water that has been supercooled, it will suddenly crystallize into ice.

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Supercooling occurs when a liquid is chilled below its freezing point, yet remains a liquid. When you do this to water, you can cause it to change to ice under controlled conditions. This makes for a great demonstration that students can try at home, too.

Colored Fire Chem Demos

Flame details from campfire

Getty Images / Danita Delimont

A colored fire rainbow is an interesting take on the classic flame test, used to identify metal salts based on the color of their emission spectra. This fire rainbow uses chemicals readily available to most students, so they can replicate the rainbow themselves. This demo leaves a lasting impression.

Nitrogen Vapor Chem Demo

All you need is iodine and ammonia to make nitrogen triiodide. This unstable material decomposes with a very loud 'pop', releasing a cloud of violet iodine vapor. Other reactions produce violet smoke without the explosion.