Volcano Experiment
Safety and First Aid
This section will only deal with the specific safety issues regarding the chemicals involved; there are
likely to be other safety issues that will need to be addressed outside the scope of this section. A full
risk assessment should be performed prior to undertaking the experiment.
Students should not ingest any of the experiment; good lab practice starts young!
There are no specific safety hazards associated with any of the chemicals used in this
experiment
Depending on your brand of food colouring, spillages may stain surfaces, clothes and
upholstery
This experiment will generate a large amount of foam; suitable containment will be required
First Aid – wash the affected area with water
Glossary
Effervescence – to give off bubbles of gas
Suggested Teaching Points
States of matter – this experiment involves solids, liquids and gases.
Acids and bases – this experiment involves the reaction of an acid and a base
Effervescence – this experiment involves the release of gas
Surface area – introduce the idea of surface area effects on rates of reaction
What to Expect
Please see the video for a detailed depiction of the experiment. It should be noted that this
experiment is not an accurate representation of the mechanism by which volcanoes erupt.
This experiment demonstrates the classic chemical reaction between an acid (namely acetic acid
present in the vinegar) and a carbonate (namely sodium hydrogen carbonate present in the baking
soda). When exposed to acids, carbonate undergoes a decomposition reaction in which carbon
dioxide is released as a gas. In our experiment, this release of carbon dioxide is what results in the
“eruption”. We recommend that washing up liquid is added to the vinegar before addition to the
baking soda as this aids in the formation of a foam occupying a large volume making the eruption
look much better!
Equipment and Chemicals
A large container to contain the foam. A plastic tray or bin liner should be sufficient.
Two glasses or disposable plastic cup for the reaction
A spoon
Vinegar
Baking soda
Washing up liquid
Food colouring
Supplementary Instructions
The exact ratio of baking soda to vinegar is not essential. However, we found that
3 teaspoons of baking soda to approximately ½ cup of vinegar. The amounts of both
reactants needed will also be dependent on the size of the containers used.
It is recommended that the vinegar / washing up liquid mixture is poured rapidly into the
baking soda to mix the chemicals together.
Ensure the resulting foam is contained to prevent excessive mess
Suggested Question for Students
What is the role of the washing up liquid? – as the gas is formed from the reaction between
the vinegar and baking soda, the washing up liquid forms lots of small bubbles to provide the
foam needed for the eruption.
What would happen if you added the baking soda to the vinegar instead? – in theory, the
same reaction would happen. However, in practise, the foam generated from the initial
reaction would push the baking soda away from the vinegar and stop the reaction.
What would happen if we used a solid block of baking soda rather than a powder? – in order
for a reaction to occur, the reactant molecules need to collide with each other. As a result,
only the molecules on the surface of a solid can react with the vinegar. By using a solid block
of baking soda, the number of molecules exposed on the surface would be less (reduced
surface area) and so the gas would be released slower.
Suggested Improvements / Student Challenge
Papier-mâché volcano – students could be allowed to design and build a volcano prior to
performing the experiment.
Investigate the ratio of baking powder to vinegar – students could investigate the effects of
altering the ratio of baking soda to vinegar has on the volcano effect. This could be used to
introduce the idea of rates of reaction etc.
Investigate the shape of the container – students could investigate the effect of altering the
shape of the container the reaction is performed in.
Clean up and Waste Disposal
No specific waste disposal protocols are required for this experiment; all waste can be washed down
the sink with water.
Spillages can be cleaned with water and paper towel.
