Classic Volcano Experiment

Now we've all heard of the baking soda and vinegar volcano but why does this work and how can we improve upon it?

The experiment.

First thing's first, build a volcano. There are many different plans for building one that can be found online. Some people use modeling clay, some people use paper mâché, some use soil, etc. It doesn't matter what method you use. Look online, feel free to be creative. All that matters is that there is a hole in the center that is water tight. In a pinch this can be done by placing a cup or jar in the middle.

The next part of the experiment is the reaction. Now there are various ways of doing this but the main three components are baking soda, vinegar, and food coloring.

Method one: Place baking soda in the container. Pour in dyed vinegar to start the reaction.

Method two: Place dyed vinegar in the container. Drop in baking soda. This works well if the baking soda is dampened and pressed into a ball but pouring powder in works just fine. Note that the bubbles could prevent loose powder from reaching the solution.

Method three: Make a saturated baking soda solution. Pour both the saturated solution and vinegar into the container at the same time. The dye can be added to either or both solutions.

Several other modifications can be done to give this experiment your own twist.

How does it work?

Baking soda is a chemical called sodium bicarbonate. Vinegar is 5-10% acetic acid in water. When acids are in water, they release hydrogen ions. These hydrogen ions react with bases to neutralize them. In the case of the reaction between acids and carbonates, a salt, water, and carbon dioxide are always produced.

Other versions of this experiment

Since wood ash is made of various carbonates, it can be substituted in place of baking soda. This can both cut costs of the experiment and add a darker color to our lava.

Any acid will do for the experiment. Citric acid is one of these. Since citric acid can be bought in a dry form, you can mix your carbonate with the citric acid. This will not react until water is added. This is a great way to blow minds by adding water to salt to see a show.

Vinegar and citric acid are both weak acids. To make the experiment more vigorous, stronger acids may be used. Easy to obtain acids include hydrochloric acid and sulfuric acid. Since these acids can be quite corrosive, goggles are a must and gloves are highly recommended. Add either of these in a well ventilated area to avoid the chance of concentrated fumes. Additionally, sulfuric acid leads to a smell of sulfur which better resembles volcanoes.

Applications learned from this experiment

Removing calcium deposits - Calcium deposits are made of calcium carbonate. As we learned from this experiment, carbonates react with acids. Pour vinegar or any other acid on calcium stains in sinks, toilets, or showers to remove them. Note that acid will react with metals as well so be careful using strong acids in metal sinks or other fixtures. It is also worth mentioning that we discussed how both the acid and base need to be dissolved in water for the reaction to commence. Since calcium carbonate is mostly insoluble in water, weak acids like vinegar will take a long time to remove the deposits.

Cheap acid neutralizer - Since wood ash contains carbonates, you can use wood ash to neutralize acid spills. This is much cheaper than using baking soda.

Cooking applications: Baking soda releasing carbon dioxide in the presence of acids is why it works well in slightly acidic foods as a leavening agent. If the food is too basic, baking powder is needed to add some acid into the reaction.

Bath bombs - Citric acid and baking soda do not react until they are dissolved. This is why bath bombs only work when wet.