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Spark Science: Oozing Pumpkin Spooky Goo!

October 19, 2017
Posted By: TELUS Spark

This spooktacular science experiment will have you itching for more. We're making a decomposition chemical reaction to ooze out spooky goo from a pumpkin! 


  • 80ml of 30% Hydrogen Peroxide
  • 25 ml of Potassium Iodide
  • Dish Soap
  • Carved Pumpkin
  • Gloves
  • Safety Gear!

To make the oozing goo we’ll be using hydrogen peroxide and potassium iodide! Hydrogen Peroxide is a reactive chemical that is used in a lot of different things! 

 In small concentrations its common uses are:

Preventing skin cuts/infection
Antiseptic mouth rinse
Killing bacteria
Fighting foot fungus
Help get rid of acne

and more!

It’s chemical formula is H2O2- and is breaking down into water and oxygen. This decomposition happens at a very slow rate. To increase the speed of this chemical reaction, we need a catalyst!

For this experiment, we are using potassium iodide as the catalyst. Adding in soap will help create boo bubbles to capture the releasing oxygen and make a spooky oozing goo squeezing its way out of the carved pumpkin. You will see steam rising out of the pumpkin for a ghostly effect because it is an exothermic reaction! 

 CAUTION: High concentrations of hydrogen peroxide can cause chemical burns. Make sure you have adult supervision and wear safety gear!

To dispose of the reaction, rinse with water down the drain or toss into garbage 


Can you make coloured spooky goo?

Have fun!

Note: If you do not have access to concentrated hydrogen peroxide and potassium iodide, use regular hydrogen peroxide and a mixture of yeast and water for a similar effect!