The Fake Volcano Recipe Experiment - The recipe is certainly real, but not the volcano.
The famous science fair volcano has got the science all wrong. A real volcano is a story of heat and pressure, but baking soda and vinegar create a chemical change. That change is the fun part, but no one needs a plaster volcano.
Materials
Quart of vinegar
Baking soda
Clear plastic bottle 12 ounces or more.
Balloons, a few, in case one gets split when attaching
Funnel
Spoon
Preparation - I usually show them everything, from the start, but this step can be done before the class starts.
Use the funnel and pour a cup of vinegar into the bottle. Wipe the funnel dry.
Use the funnel to put one teaspoon of baking soda into the balloon. Be sure to stretch and fill the balloon before attaching it to the opening.
Stretch the balloon upside down, and stretch the balloon lip around the opening of the bottle. The carbon dioxide won’t be released until you empty the soda into the bottle by lifting up the balloon.
At this point, it’s stable and can sit that way for an hour or two,
When the class is ready Ask the students to explain what they know about solids and gasses, and what they know about dissolving a solid into a liquid. Announce that you will combine a liquid and a solid in the bottle they can see. What would you think if the mixture in the bottle made the balloon blow up?
Discuss this until they’re ready to know what they’re seeing. Flip the balloon and place it on a table or hold it at arm’s length. The gas escapes. We can’t see the gas but we can see it takes up space and it has so much pressure it can blow up the balloon. You can shake the bottle to dissolve more soda as it’s happening.
The foam actually reduced while the balloon bulged. Chemistry is the science of change. The change we saw is that a gas was released when the vinegar and baking soda mixed. Can you believe it? No magic, just science. A solid mixed with a liquid made a gas !
