Audubon for Kids

Create a Mini Ocean to Watch How Climate Change Affects Seashells

How do carbon emissions affect ocean animals that live in shells? Find out in this easy home experiment.

Climate change is making the Earth warmer—its air, oceans, land, and ice. That’s why it’s sometimes called global warming. This happens because an invisible gas called carbon dioxide enters the Earth's atmosphere and traps heat. People release carbon dioxide when we burn certain kinds of fuels (such as coal, oil, gas, and wood) to produce energy.

Climate change has other effects besides making things hotter. The same air pollution (carbon dioxide) that warms our planet also changes our oceans' chemistry. That’s because carbon dioxide dissolves into ocean water. Dissolving is a chemical reaction that occurs when a solid or gas completely mixes in with a liquid. If you’ve ever mixed sugar into hot water or tea, you’ve helped dissolve a solid (sugar) into a liquid (water). The sugar looks like it disappears, but it actually becomes part of the water solution.

When carbon dioxide dissolves into seawater, we can't see it. But it makes the ocean more acidic. This is known as ocean acidification. What is acidity? It’s hard to explain, but you may already know what it is if you’ve eaten acidic foods. Acidic foods, like lemons, often taste sour or tart. The ocean is so big and so salty that climate change won’t make seawater taste sour to us. But the chemical change still affects ocean animals, especially animals that live inside a shell, like snails, clams, mussels, and lobsters.

If shelled animals are hurt by climate change, then animals like birds that eat those animals are also harmed. This is one reason it's important to stop climate change: To protect all the ocean animals that live in shells and the ones that rely on them for food. 

We need energy to create the electricity that powers our lamps, televisions, and air conditioners. That means that if we want to stop climate change and global warming, we need to find new sources of energy that don't create air pollution. Examples include solar panels, which turn sunlight into electricity, and wind turbines, which turn gusts of wind into electricity.

In this simple experiment, you will find out what happens to shelled animals when seawater gets too acidic. All you need is a few seashells and some items you can find in your kitchen.


Glass containers
White vinegar
Salt (optional)
Masking tape, Post-it notes, or other labels


You're going to test how different liquids affect seashells when left in the liquid overnight. You need at least two seashells, but can test more liquids if you have more seashells at home.

  1. Line up your containers on the counter and put a seashell in each one.
  2. Pour tap water into your first container so that it entirely covers the shell. Take a piece of tape and write “water” on it, and stick it to the container. It’s important to label your containers as you go so you don’t mix them up!

    Bonus: You can also make an approximation of “seawater” in the kitchen by dissolving 3 ½ teaspoons of table salt into 4 ¼ cups of tap water (or more to taste).
  3. Pour vinegar (which is an acid) into your second container so it entirely covers the shell. Like with the first jar, be sure to label this one with “acid.” Climate change won’t make the oceans as acidic as vinegar. But using a stronger acid will make the experiment happen within your child’s attention span.

    Bonus: If you have more shells, you can create different vinegar solutions by mixing with water. Try half vinegar and half water.
  4. Look at your containers. Can you see any visible changes? You might already notice bubbles forming around the seashell in the vinegar container. This is evidence of a chemical reaction. The acetic acid in the vinegar is reacting with calcium carbonate in the shells. When they react, they release carbon dioxide—that’s the bubbles.
  5. Put the containers in a safe place and let them sit undisturbed. Check on them after a few hours, and again after 24 hours. What happened to the shell in the vinegar water? If it’s a thinner shell (like a scallop shell), it might have gotten even thinner. If you remove it from the container it might break apart in your hands. If there’s no difference after 24 hours, pour out the vinegar and refill it with fresh vinegar. Leave it in there longer, if you like, and keep checking to observe the chemical reaction for as long as your child stays interested. You can take a piece of paper and record the date, time, and observations as you go—like a lab notebook.
  6. What does this experiment tell us about how climate change impacts ocean animals with shells? Carbon dioxide reacts with seawater to form carbonic acid, which makes the water more acidic. Over time acidic seawater will dissolve mollusk shells and harm the animals living inside, which in turn can hurt animals higher on the ocean food chain, including seabirds.
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