Welcome to Term 2! There must be an elephant in the room! ‘Elephants Toothpaste Demonstration’

The Year 7 cohort have been exploring ‘mixtures’, including solutions during Term 1. They identified the solvent and solute in solutions and investigated a range of physical separation techniques such as filtration, decantation, evaporation, crystallisation, chromatography and distillation.

During the first lesson back in Term 2, students of 7A were eager to put their scientific inquiry skills to the test as the ‘Elephant’s Toothpaste Experiment’ was demonstrated, as suggested by the students. They were required to predict what would happen before the demonstration, record their observations during the demonstration, and explain the results.

‘First things first! ‘Students put on their Safety Equipment, including gloves, eyes protection, and a lab coat. A safety screen was placed between the students and the chemical reaction involved in the demonstration.

The following method was used to conduct the experiment, materials were prepared earlier by our amazing laboratory technician:

Do not try this at home without proper safety equipment. 

  1. Place a 500ml measuring cylinder in the glass trough in a red tub.
  2. Measure 150ml of 17.5% hydrogen peroxide and place in the 500ml measuring cylinder.
  3. Add two squirts of detergent and run some different food colourings down the side of the cylinder.
  4. Add 30 ml of Potassium Iodide and observe the reaction.

Behold! The Potassium Iodide initiated the breakdown of hydrogen peroxide into water and oxygen. The mixture heated up and the oxygen and water vapors that formed frothed up the liquid soap.

Students were introduced to the concept that a chemical change involves substances reacting to form new substances.

Ms Roxanne Liemareff
Science Teacher