Join us in a search for the science behind seashells as we perform a seashells in vinegar experiment. Seashells are fascinating, beautiful, and come in a nearly unlimited assortment of shapes and sizes. On this Excavating Adventure, we will explore the exciting world of shells. We’ll learn fun facts and other amazing information about these natural treasures. We’ll then dive deep into seashells by setting up and observing what happens when you put seashells in vinegar.



WHAT WE’RE GOING TO LEARN (OBJECTIVES): Understand what seashells are made of, where seashells are found, and we'll discuss different types of seashells.




Various seashells

Safety Goggles


Several clear glasses or jars


Adult supervision




A mollusk produces calcium carbonate and uses proteins from its mantle, laying down layers of it over its lifetime to produce its shell.

Most seashells are dextral which means they open to the right. Shells that open to the left are called sinistral and are much rarer.

Seashells can be quite plain to very elaborate. Many elaborate shells come from tropical areas where there are many predators. These spikes, spines, and colors are designed to ward off predators, while smoother shells are able to move faster and avoid detection.

The first known currency (money) ever used was seashells.

Cone snails contain one of the most dangerous natural toxins to humans.

The oldest seashell collection that has been discovered by archeologists was found in the ruins of the ancient city of Pompeii and dates back to 74 AD.

It is estimated there are between 70,000 to 120,000 known species of creatures that create shells. These creatures are either bivalves which have two shells connected by a hinge (think of a clam), and gastropods which have one shell and no hinge (think of a snail).

Conch is a common name of a number of different medium to sometimes larger sized sea snails. The official term for someone that collects seashells is a conchologist.



Now that we know a little bit more about seashells, let’s set up our seashells in vinegar experiment. As we learned earlier, seashells are made of calcium carbonate. Calcium carbonate is a base, and if combined with an acid like vinegar, a chemical reaction will occur. Let’s put some seashells in vinegar and see what we can observe.

Setup one of the glass jars, add enough water to cover the shell you are going to place inside, and mix in salt until it no longer dissolves. This container will simulate our seawater and will act as our control. Go ahead and add a shell to this mixture. Be sure to label this container so you know it is your control.

Now set up one or more of the other glass jars. Add a seashell to each jar. If you are lucky enough to have some shells of different shapes and sizes, then place a different shell in each container. Now add vinegar to each jar, making sure to completely cover each shell.

Wait 24 hours and observe and write down any changes. Repeat after another 24 hours and so on.



What happened to the seashells?

What do you think would happen if you used lemon juice instead of vinegar?

Did you observe bubbles on the seashells? If so, what do you think caused the bubbles?



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