Johann Gahn

-in-

Captain Peroxide

Meets the

Forelli Bros.

A film by Ian Hill

 
"It's like The Godfather and The Engineer's Manual for Building Demolition combined!" -- Ernest Hemingway
"Dynamite!....well, actually, manganese dioxide and hydrogen peroxide, but explosive nonetheless!" -- William Shakespeare
"It's better than my own Doctor Zhivago!" -- Boris Pasternak
"A Brilliant Performance!" -- The New York Times Johann Gahn was a chemist and a mineralogist most noted for his discovery of manganese dioxide in 1774. This discovery plays a crucial role in my experiment, which is illustrated by the following formula. "A Must See!" -- The Washington Post

 

 
MNO2
  
 
H202 ----------> H2 + 02
  
     

By introducing a catalyst (in this case MNO2) to a compound we can witness a decomposition reaction.

Materials: A graduated cylinder, tissue paper, water, 30% hydrogen peroxide, manganese dioxide, string, scoopula, apron, gloves, and safety goggles. A fume hood is also highly recommended.

 

Procedure: Place 75 mL of the 30% hydrogen peroxide solution in a graduated cylinder. Add 25 mL of water, making the total 100 mL.

On a square piece of tissue paper, folded a few times for thickness, place two small scoops of manganese dioxide in the center. Note: the more manganese dioxide you use, the more explosive the reaction. Just a little bit is recommended. Fold the piece of tissue into a bundle and tie it with the string. Make the string long enough that you can lower the bundle into the graduated cylinder from a safe distance.

When you have made the little packet, lower it slowly into the graduated cylinder from the side. Do not lower it from directly above the cylinder as that is in the way of the reaction.

If the packet is too large to fit inside the cylinder, re-pack it with your fingers until it is the right size.

 

If you would like to see the experiment, click on a link below. If you're seriously interested in the experiment then forget any references to the Mafia that you might find. Due to some QuickTime quirk, the audio may be messed up, but believe me when I tell you that the movie's really smashing.

 

 

 

More on Johann Gahn:

He was born in Voxna, Sweden, in 1745. He worked at the University of Uppsala, discovering manganese dioxide (MNO2) in 1774. He and colleague Carl Wilhelm Scheele shared the discovery of phosphoric acid in bone material in 1770.
 

 

What was life like in Johann's time?

 

Cultural Fact: When Johann discovered manganese dioxide in 1774, Ludwig Van Beethoven was four years old.

 

Historical Fact: In 1774 the Founding Fathers of the United States were still shaking their fists at the British on the fourth anniversary of the Boston Massacre.

 

Scientific Fact: It was in this atmosphere of bold adventurism and discovery that British Secretary of State John Montagu invented the sandwich and was later blamed for British defeats in the American Revolution.

 

A better scientific fact: In 1774 Joseph Priestly discovered oxygen ("Fire Air") by heating the red oxide in mercury.

 

 

 

Question: What does the 2 mean in MNO2?