1Daily Warm-Up Exercises 1

Day 23What is the main ingredient in limestone?

calcium carbonate

What was the purpose of the seawater investigation we did on Day 22?

The purpose was to try to find out where the calcium carbonate comes from and how it gets into limestone.

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Testing for Calcium Carbonate(Part 2)

Investigation 5

Limestone

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Review Limewater InvestigationWhy did we blow into the limewater?

The limewater represented ancient seawater. Blowing into it simulated marine organisms exhaling in an ancient sea.

What happened?The water got cloudy and a white powder settled to the bottom of the cup.

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Plan an Investigation• We have some materials that might be found

in the sea. Plan an investigation to see if any of these materials might cause limestone to fizz.

• Make a chart on the back of lab sheet 37 to organize your observations.

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ResultsWhich materials fizzed in acid?

white powderoyster shellsOther shells

How do you think limestone forms? What process might produce a rock that fizzes?

Write your thoughts on the back of your lab sheet.

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Calcite• Limestones fizz in acid because they contain

calcite (calcium carbonate)

• When acid reacts with calcite, carbon dioxide gas is produced. The fizzing is the CO2 being released.

• Where does the calcite come from?

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One Way• Some marine organisms have shells made of

calcite.

• When the animals die, the shells settle to the bottom.

• Layers pile up, and the shells get compacted and cemented together to form limestone.

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Another Way• Marine organisms exhale CO2 into the

seawater.

• The CO2 reacts with calcium in the water to form calcite powder.

• The calcite powder settles to the bottom and gets compacted and cemented together to form limestone.

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Finish Seawater Investigation• Answer the questions at the bottom of the

Seawater Investigation worksheet.

Finish reading Coconino Stories pg. 73

• Define in your journals:– Crossbedding– Uniformitarianism

Crossbedding

Crossbedding

Crossbedding

Uniformitarianism• The present is the key to the past

• Geologists assume that the processes (deposition, erosion, etc) they see happening today work exactly the same way through out geological history.

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