Teacher instructions

Work through this resource material in the following sequence:

20 minutes

Tune in: What will change?

20 minutes

Find out: Experiment time!

20 minutes

Reflection: What did we learn?

Tune in: What will change?

Step 1. Discuss:

what is ocean acidification? Students might not have heard this term before, but encourage them to take an educated guess based on the words. Basically, it means the ocean is becoming more acid-y.
what might be causing ocean acidification? The easy answer here is: climate change. Specifically, greenhouse gas emissions (we'll get into this later).
what might happen to the living things in the ocean if the ocean becomes more acidic? If students can't come up with an answer, ask them how they'd like to be having a bath, only for you to pour more and more acid into it. What might happen to their skin? Students might also be familiar with the coral bleaching of the Great Barrier Reef.

Step 2.

Explain the experiment to your students.

Step 3.

Students write their predictions in the first section of the Student Worksheet.

Find out: Experiment time!

Step 1.

Using the pen, label the cups as follows: “mussel + water”, “oyster + water”, “scallop + water”, “mussel + vinegar”, “oyster + vinegar” and “scallop + vinegar”.

Step 2.

Look closely at each shell. Pick up each shell and rub it between your fingers. Record how each shell feels, in particular the shiny surface inside the shell. You can take photos if you like.

Step 3.

Place the shells into the cups and add water to the water cups and vinegar to the vinegar cups, making sure that the shells are completely covered.

Step 4.

Watch the shells for 15 minutes to see if there are any changes to the shell, in particular any bubbling. Note this down.

Step 5.

Examine the shells once a day for three days. You can take the shells out to feel them and try to bend them a little bit. Record any changes in appearance, texture or flexibility.

Reflection: What did we learn?

Calcium - in the form of calcium carbonate - is a component of many sea shells. When calcium carbonate comes into contact with an acidic substance, a chemical reaction takes place, releasing bubbles of carbon dioxide gas.

Losing calcium to this chemical reaction makes the shells more flexible, leaving the animals inside the shells more vulnerable. Eventually, the shells can even rot, or become very brittle and easily broken by the teeth of predators.

Our teeth are also made of calcium, although they are protected by a layer of enamel. But we also put a lot of acids in our mouths - especially soft drink! - which can wear away our teeth in exactly the same way, giving us cavities.

We might think, well, this is just an experiment. But the ocean our oceans are actually becoming more acidic.

When the concentration of Carbon dioxide (CO₂) in the atmosphere increases due to our cars and power plants releasing greenhouse gases, the ocean tries to help out by taking it from the air or sequestering the CO₂ from the atmosphere. In this way, the oceans are moderating the amount of greenhouse gases in the atmosphere. Without the oceans, atmospheric CO₂ levels would be even higher.

Unfortunately, this process may cause long-term damage to life in the oceans. As CO₂ is transferred into the ocean it lowers the pH of the water and creates a more acidic environment. Ocean acidification is recognised as one of the most significant looming environmental problems we will have to face.

Where our seashells might have been happy and strong in their habitats, as the physical conditions change and the oceans become more and more acidic, the consequences are felt in the growth and survival of living things.

How Does Pollution Affect Sea Shells?

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