Elephant's Toothpaste Experiment

Well, it's not really toothpaste meant for an elephant, but that's the name of the experiment...

The experiment consists of mixing potassium iodide (KI) salt with a strong oxidizer consisting of 30% hydrogen peroxide (H₂O₂) and a little bit of liquid dish soap in a standard boiling flask. The test setup is shown below courtesy of my intrepid laboratory assistant.

  

Cameron the Chemist...

  

Potassium iodide (KI) salt has numerous medical applications, and like all salts, rapidly dissociates in certain solutions (such as water, etc.). It's provided in 130 mg tablets for 'emergency purposes' which is a politically correct way of saying 'atomic war'. Our sample is a laboratory grade bottle of the crystalline stuff.

The oxidizer we use is simple hydrogen peroxide (H₂O₂), although our brand is a little stronger than the stuff you buy at the drugstore (think rocket fuel). Those jet packs from the 1960's that NASA and experimenters used ran off a similar concentration, which instantly oxidizes anything it touches.

Our chemical reaction to make elephant's toothpaste is shown below.

The dish soap is added to make the bubbles (and the mess)...

The reaction produces an aqueous solution of potassium (K) and iodine (I) while releasing copious quantities of oxygen (O₂) and heat. The O₂ mixes with the soap to produce the toothpaste effect. A slow motion video of the experiment is shown below demonstrating the effect of 'squeezing the tube of toothpaste'.

 

 

The initial reaction is shown again in the series of photographs below and roughly constitutes the first second after the potassium iodide is added to the boiling flask.

 

Adding the KI Crystals		The Reaction Begins...
The H2O2 Solution Heats Up Rapidly...		O2 Gas and Steam is Released

 

The reaction byproducts are relatively easy to clean up. The bubbles consist of soap and iodine, so it's a good idea to wear gloves as it will stain your hands a delightful golden orange color.