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Let’s Talk Science and the Royal Society of Canada have partnered to provide Globe and Mail readers with relevant coverage about issues that affect us all – from education to the impact of leading-edge scientific discoveries. Let’s Talk Science offers a number of fun activities to get youth engaged in STEM.

Create a model of an erupting volcano and learn about the structures of a stratovolcano in this hands-on activity.

What You Need

● Baking soda

● Small jar or bottle (e.g. baby food container)

● Dish detergent

● Food colouring (optional)

● Funnels

● Measuring spoons

● Shallow dish (e.g. aluminum tray or pie plate)

● Vinegar

What to Do

  • Place a bottle in the middle of a shallow dish.
  • Put 125mL of vinegar inside the bottle.
  • Add 10mL of dish detergent and a few drops of food colouring (optional).
  • Add 25mL of baking soda and quickly put a funnel over the top of the bottle.

Cross-section through a stratovolcano

  • Large magma chamber
  • Bedrock
  • Conduit (pipe)
  • Base
  • Sill
  • Dike
  • Layers of ash emitted by the volcano
  • Flank
  • Layers of lava emitted by the volcano
  • Throat
  • Parasitic cone
  • Lava flow
  • Vent
  • Crater
  • Ash cloud

What’s happening?

A volcano is produced over thousands of years by a build up of heat and pressure under the Earth’s crust. When that pressure gets high enough, the crust can rupture and molten lava rises to the surface and rushes through the crack.

While it can be difficult to model with an experiment, this activity shows you what an erupting volcano with flowing lava might look like. It provides an example of a chemical reaction that mimics a physical phenomenon.

Chemically, when vinegar is added to baking soda, a reaction occurs in which carbon dioxide gas is produced. The gas produced during the reaction, and any liquid remaining, mixes with the detergent to form foam. Eventually, the gas builds up enough pressure to force the foam out of the top of the bottle, creating an erupting volcano effect.

Why does it matter?

The reaction that occurs between vinegar and baking soda is used to fluff up cakes and easy breads. Substances called “leavening agents” are added to baked goods before cooking in order to produce the carbon dioxide that causes them to rise. In fact, there is a lot of chemistry involved in baking delicious cakes and breads!

Investigate further

● Think of a way you could blow up a balloon using this chemical reaction. Remember that gas is produced.

Discover more free, English and French, Let’s Talk Science hands-on STEM activities, resources and events online.

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