minerals in the soil are used up. For the plant to grow it needs minerals from the soil. When parts of the plant die, the plant material rots and minerals go back into the soil. So that's why I think that how much the plant will grow will depend on the minerals in the soil.

The gases, oxygen, carbon dioxide and water vapor just keep getting used over and over. What I'm not sure about is if the gases get used up. Can the plant live if there is no carbon dioxide left for photosynthesis? If there is no carbon dioxide, will the plant respire and keep living?

I'm pretty sure a plant can live for a long time sealed up in a jar, but I'm not sure how long or exactly what would make it die.

STUDENT S: I believe that putting a small plant in a closed mayonnaise jar at 60-80°F is murder. I believe that this plant will not last past a week (3 days). This is so for many reasons. Contained in a jar with constant sunlight at 80°F the moisture in the soil will most likely start to evaporate almost immediately. This will leave the soil dry while the air is humid. Since we are in a closed container no water can be restored to the soil (condensation). This in turn will cause no nutrients from the soil to reach the upper plant, no root pressure!

Besides this, with photosynthesis occurring in the leaves, at least for a short time while water supplies last, the CO2 in the air is being used up and O2 is replacing it. With no CO2 and no H2O, no light reaction and/or dark reaction can occur and the plant can't make carbohydrates. The carbohydrates are needed for energy.

In conclusion, in a jar closed from CO2and water, plants use up their resources quickly, preventing the equation CO2 + H2O-> C6H12 O6 and O2 and, therefore, energy from carbohydrates.

This jar also works as a catalyst to speed up the process by causing evaporation of H2O through incomplete vaporization. This would shut down the root hair pressure in the plant which allows water (if any) + nutrients to reach the leaves. All in all the plant will not live long (3 days at the most then downhill).

Judging the quality of information contained in a justification requires consensus on the information contained in it and then using certain standards to compare that information with the information in the rubric. Standards that might be applied include the scientific accuracy of the information in the justification, the appropriateness of the knowledge to the student's age and experience, the sophistication of the knowledge, and the appropriateness of the application of the knowledge to the situation.

Foremost, judgments about the quality of the information contained in the justification should take into account the accuracy of the information the student used in crafting the response. Student S's justification contains some misinformation about the water evaporation-condensation cycle and about dynamic equilibrium in closed systems. The statements in which this inference is made are "the moisture in the soil will most likely start to evaporate almost immediately. This will leave the soil dry while the air is humid. Since we are in a closed container no water can be restored to the soil (condensation)." The student's statement that "soil in the container will be dry while the air is humid," suggests lack of knowledge about equilibrium in a closed system. In contrast with Student S's misinformation, Student E's justification contains information that is neither unusually sophisticated when viewed against the content of most high-school biology texts, nor erroneous.

Judgments about the appropriateness of the information are more difficult to make. A person familiar with the biology course



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