Writing a Conclusion

For this lab, you will concentrate on writing concluding statements rather than the whole report. A helpful tool when writing a conclusion is this mnemonic device:

When you write your concluding statements, make sure to include summary statements that address each of parts above. Make sure to address whether or not the results of the experiment supported your hypothesis. Also, discuss any possible sources of error and how the experiment could be improved. In your reflection, address the following questions:

1. After the three days, what happens in each test tube? Why?
2. What is necessary for rust to occur?
3. How does this activity demonstrate the fate of oxygen in Earth’s early atmosphere, when iron in the oceans was still removing oxygen from the air?

Download your lab report form to enter your conclusion.

Lab Instructions

Earth’s ancient atmosphere could not support life because it didn’t contain enough oxygen. The oceans of ancient Earth contained high amounts of iron. The iron in the oceans removed all the oxygen from the air by reacting with it. Once there was no unreacted iron in the oceans, oxygen was able to build up in the atmosphere. But how can iron remove oxygen from the atmosphere? What is formed when iron and oxygen combine?

You will learn the answer to these questions by performing a virtual lab. Perform the three tests below using the virtual lab. Press the corresponding button on the virtual lab to perform each test.

Test #1

Drag three test tubes to the test tube rack.

Add a small amount of calcium chloride to each test tube.

Add 3–4 nails to each test tube.

Now add a rubber stopper to each test tube.

Now click "Start."

Observe the nails and record changes in your notes.

Test #2

Drag three test tubes to the test tube rack.

Add a small amount of boiled water to each test tube.

Add 3–4 nails to each test tube.

Now add a rubber stopper to each test tube.

Now click "Start."

Observe the nails and record changes in your notes.

Test #3

Drag three test tubes to the test tube rack.

Add a small amount of tap water to each test tube.

Add 3–4 nails to each test tube.

Now add a rubber stopper to each test tube.

Now click "Srt on a stop watch

Observe the nails and record changes in your notes.