Respiration Lab

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Describe the process of external gas exchange. What gases are being changed? Why?

External gas exchange is between the air and lungs. Oxygen goes into the blood from the air via alveoli. Carbon dioxide goes into alveoli into air from blood. You breath out carbon dioxide because of cellular respiration. O2 + glucose → H2O + CO2 + ATP

Procedure: 

Observations:

Part A - Aerating of lime water had no changes (left test tube). The test tube that had carbon dioxide aired into by a human turned cloudy ( right test tube).

Part B - The beaker to the left turned into a light green was aerated which means it is neutral. The beaker to the right had distilled water and had a human being breathed carbon dioxide out into it turned into a vibrant yellow which means its highly acidic.

Part C -

Amount of breaths taken in 60 seconds; 28, 25 and 18.
Amount of breaths taken in 30 seconds; 18, 14 10.

The results which were taken in thirty seconds are slightly higher (if multiplied by 2) to equal out the amount of time given to breath. This test was mostly subjected to human error so therefore it is not conclusive.

Questions:

Part A

1. What does a change in color in the lime water indicate?
A change in color indicates chemical change.

2. What is the purpose of the control test tube?
To compare the difference between how the lime water is affected by oxygen and carbon dioxide.

Part B

3. What does the change in color of the universal indicator mean?
When your body breathes out C02 and it combines with H2O, the pH levels change and the H2O becomes acidic.

4. What is the purpose of the control beaker?
The purpose is to compare and see the results of both test tubes

5. Explain what is happening in the test beaker of water.
Both of the beakers remained the same until the universal indicator was added. The beaker that was aerated turned into a light green color, symbolizing that it is neutral. The beaker that we breathed out carbon dioxide into turned yellow, symbolizing it is acidic.

6. Why does your blood not become acidic?
 Our blood contains hydrogen with hemoglobin molecules which regulates our pH levels. That keeps are blood from not becoming acidic.

Part C

8. Explain the results for Part C. What happened to the breathing rate? What mechanism is responsible for this change?
I think part C failed due to human error. The participants continuously lost count throughout the course of the test.