“Iron volcano” experiment

How to make a volcano of two powders

The say­ing “You can’t judge a book by its cov­er” also ap­plies in chem­istry: some­times the dullest and plainest-look­ing sub­stances dis­play in­cred­i­ble prop­er­ties. For ex­am­ple, in this ex­per­i­ment you can make a sparkling vol­cano from two pow­ders.

Safe­ty pre­cau­tions

Ob­serve safe­ty rules when work­ing with flame and ex­treme­ly hot ob­jects. Wear pro­tec­tive gloves, a mask and glass­es, and work in a well-ven­ti­lat­ed room.

Warn­ing! Don’t try to re­peat this ex­per­i­ment with­out a pro­fes­sion­al su­per­vi­sion!

Reagents and equip­ment:

  • iron pow­der (10 g);
  • potas­si­um ni­trate (30 g);
  • con­tain­er with sand;
  • lighter;
  • beaker;
  • rod.

Step-by-step in­struc­tions

Mix potas­si­um ni­trate and iron pow­der in the beaker. Stir thor­ough­ly. Make a hol­low in the sand and pour in the re­sult­ing mix­ture. Ig­nite. Watch the vol­cano erupt.

Pro­cess­es de­scrip­tion

Potas­si­um ni­trate is a strong ox­i­diz­er. When heat­ed, it de­com­pos­es into oxy­gen, which re­acts with the iron pow­der, ox­i­diz­ing it to ox­ides. A great deal of heat en­er­gy is re­leased, caus­ing the sand to melt, and the mix­ture starts to re­sem­ble vol­canic lava.

2КNO₃ = 2KNO₂ + O₂

Fe + O₂ = FeO + Fe₂O₃