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Sea Shells with Vinegar

Sea Shells with Vinegar

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Science Fair Project Description

Seashells are the hard, outer coverings that mollusks produce, in order to protect themselves from predators; it also serves as a form of shelter form the elements. Seashells come in a wide range of shapes, sizes, and colors; however, they all are created from the same material - calcium carbonate. In this science fair project, you will investigate how seashells react when exposed to an acid.
Complexity level:6
Time required:The time required for interaction between the vinegar and seashell may take up to a week.
Safety concerns:


The hypothesis is that the vinegar (acid) will react with the calcium carbonate (base) in the sea shell, causing the sea shell to disintegrate.


Acids and bases are different from each other. When we add an acid to water, it forms hydrogen ions. When a base is added to water, it forms hydroxide ions. Hydrogen ions and hydroxide ions cause different kinds of chemical reactions. We can measure this by checking the pH level of the water. A pH of 1-6 means it's an acid, while a pH of 8-14 means it's a base. If it's pH 7, it's neutral. Seashells are made of calcium carbonate, which is a base. Vinegar, on the other hand, is an acid. When they come into contact, a chemical reaction happens. The acid from vinegar reacts with the basic calcium carbonate in the seashell, dissolving it and releasing carbon dioxide gas. Ocean acidification is a problem that can harm marine life. When the ocean becomes more acidic, it can make the shells and skeletons of animals dissolve faster. Animals like corals, sea urchins, snails, and oysters have to spend extra energy to fix their damaged shells or make them thicker to survive. This is a problem because when animals use energy to repair or thicken their shells, it can affect their growth and lower their population. This can have a negative impact on other animals in the food chain, like whales and even humans. The ocean plays a big role in reducing carbon dioxide in the atmosphere. Animals with hard skeletons, like plankton, store carbon in their bodies. But with ocean acidification, their skeletons dissolve, which could make it harder to reduce the carbon dioxide in the air and fight against climate change.

Scientific Terms

Calcium carbonate, Acid, Base, pH, hydrogen ion, hydroxide ion, neutral.


  • 2 sea shells

  • vinegar

  • water

  • 2 jars that are large enough to hold the sea shell


  1. Place one sea shell in each jar. Label one jar "vinegar", and the other "water".

  2. Pour enough vinegar in the "vinegar" jar to cover the sea shell.

  3. Pour enough water in the "water" jar to cover the sea shell.

  4. Place the jars in a safe place where they will not be disturbed.

  5. After 1 day, check the jars. What do you see?

  6. After a week, check the jars again. What do you notice about the sea shell in vinegar and the one in water?


After a week, the sea shell dissolved in the vinegar, but not the sea shell in water. There were small bubbles on the sea shell in the vinegar.


When you put a sea shell in vinegar, something interesting happens. The vinegar contains a substance called acetic acid, which is a type of acid. The shell is made of a material called calcium carbonate. When the shell meets the acid, a reaction occurs. It creates bubbles of carbon dioxide gas, and the shell starts to dissolve. This happens because the acid reacts with the calcium carbonate in the shell. It's like a mini chemical reaction that changes the shell.

Also consider

Variations of this experiment could include testing different acids, such as lemon juice or orange juice, or soaking the sea shell in vinegar with baking soda.


The ocean's water is becoming acidic. There are lots of sea shells in the ocean, and the ocean's water is becoming acidic. What will happen to the sea shells? Learn from the Exploratorium museum:

"How Are Sea Shells Made?" from eHow

Related videos

Hey there! Here are some awesome videos about this science project that we think you'll really like. They're not only super fun, but they'll also help you learn more about the science behind the project. So sit back, relax, and get ready to have some fun!!
Have you ever wondered what happens to seashells when the ocean becomes more acidic? Check out the following video that shows an experiment comparing seashells in vinegar, which mimic the acidic ocean water, with the control of seashells in regular water. Can you guess what happened? The results were surprising and taught us how changes in the ocean can affect marine life. This experiment is a great way to learn about the powerful chemical reaction between acids and bases and understand the shocking impact of ocean acidification.
Eggs are also made of calcium carbonate like seashells. Be prepared for a surprise when a raw egg soaks in vinegar! Find out what happens in this surprising chemistry experiment!
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