A science class set up an aquarium experiment with an Elodea plant as seen in the picture below. The class observed small bubbles on days 1 and 2, but no bubbles on day 3. The class concluded that the bubbles were caused by photosynthesis. What should the class do so that the bubbles will reappear?
Add glucose to the water
Add carbon dioxide to the water
Change the light's color to green
Move the light closer
The class should add carbon dioxide to the water. Elodea plants undergo photosynthesis to produce glucose and oxygen from carbon dioxide, water, and light energy. The bubbles observed were most likely oxygen produced during photosynthesis. If there are no bubbles on day 3, it may be because the Elodea plant has used up all the available carbon dioxide. Providing more carbon dioxide will allow the plant to continue photosynthesis and produce oxygen bubbles.
To understand how to make the bubbles reappear, let's first understand the process of photosynthesis and what the Elodea plant needs for it to occur.
Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose. During this process, plants take in carbon dioxide (CO2) from the air, water from their surroundings, and capture light energy through chlorophyll pigments found in their cells. Oxygen is released as a byproduct of photosynthesis.
In the given situation, the class observed bubbles on days 1 and 2, suggesting that photosynthesis was occurring. The bubbles observed were most likely oxygen being released by the Elodea plant.
Now let's evaluate the options provided:
1. Add glucose to the water: Glucose is the end product of photosynthesis and is produced by the plant itself. Adding glucose to the water would not stimulate photosynthesis because the plant is already capable of producing it.
2. Add carbon dioxide to the water: Carbon dioxide is a key ingredient required for photosynthesis. By adding carbon dioxide to the water, the plant will have more of this necessary component for photosynthesis to occur. This option, therefore, has the potential to make the bubbles reappear.
3. Change the light's color to green: The color of light absorbed by chlorophyll pigments is primarily in the blue and red spectrum, rather than green. Changing the light's color to green would provide light that is poorly absorbed by the plant, reducing the efficiency of photosynthesis. Thus, this would not be the correct option to make the bubbles reappear.
4. Move the light closer: Light is crucial for photosynthesis as it provides the energy needed to drive the process. Moving the light closer to the plant would increase the intensity of the light, potentially providing more energy for photosynthesis to occur. This option also has the potential to make the bubbles reappear.
Based on the explanations above, the two options that have the potential to make the bubbles reappear are to add carbon dioxide to the water or to move the light closer to the Elodea plant.