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Saturday, August 7, 2010

Ocean Acidification

Did you know that the ocean absorbs carbon dioxide from the air?

Well the year 5 and 6 students know this. They also found out that when lots of carbon dioxide goes into the ocean, the ocean can become more acidic. This is bad news for animals living in the ocean who have a shell or exo-skeleton made from calcium carbonate. (eg - shell fish, coral, crabs)

When calcium carbonate is exposed to acid it starts to go soft. This means that the animals shells or exo-skeletons wont grow so well.

To demonstrate this we put an egg into vinegar and watch what happened. (Egg shells are made from calcium carbonate and vinegar is an acid.)

Our eggs are still in the vinegar so check back next week to find out what happened.



We also tested a range of substances to work out if they are acids, bases or neutral.

We tested milk, soap, vinegar, sugar, baking soda, and dishwashing liquid.

To test each substance we dropped a small amount on indicator paper.

Red/Pink = acid
Purple = neutral
Blue/Green/Yellow = base

Lemons were definitely an acid. They made the indicator paper go really red.


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