How to make a foam monster

"Elephant Toothpaste" at home

Safe­ty pre­cau­tions

Wear pro­tec­tive gloves, eye­wear, and a mask. Per­form this ex­per­i­ment in a well-ven­ti­lat­ed area, and on a plas­tic tray or dis­pos­able table­cloth.

Reagents and equip­ment

  • 100 mL hy­dro­gen per­ox­ide so­lu­tion (we rec­om­mend 30%: the high­er the con­cen­tra­tion, the more spec­tac­u­lar the re­sult);
  • 50 mL sat­u­rat­ed potas­si­um per­man­ganate so­lu­tion;
  • liq­uid soap;
  • food col­or­ing (dye);
  • 2 glass­es;
  • beaker;
  • glass rod.

Step-by-step in­struc­tion

Pour some liq­uid soap and dye into the cylin­der and add 100 mL 30% hy­dro­gen per­ox­ide so­lu­tion. Mix thor­ough­ly. Quick­ly add 50 mL sat­u­rat­ed potas­si­um per­man­ganate so­lu­tion. Ob­serve the rapid for­ma­tion of foam!

Process de­scrip­tion

The in­ter­ac­tion be­tween potas­si­um per­man­ganate and hy­dro­gen per­ox­ide pro­duces gaseous oxy­gen, which makes the soap foam.

2KM­nO₄ + 3H₂O₂ → 2KOH + 2M­nO₂ + 3O₂ + 2H₂O

An­oth­er re­ac­tion is oc­cur­ring in par­al­lel: the man­ganese diox­ide that forms dur­ing the above re­ac­tion cat­alyzes hy­dro­gen per­ox­ide’s de­com­po­si­tion to oxy­gen and wa­ter.

2H₂O₂ → 2H₂O + O₂