Question

Phytoplankton use sunlight to gain energy through photosynthesis. As a result of the Law of Conservation of Energy, phytoplankton cannot gain more energy than it consumes. A closed system consisting of an aquarium, phytoplankton, and sunlight is set up. Which of the following methods would best demonstrate the Law of Conservation of Energy? (3 points)
A) Measure the mass and temperature of the water. Then cover the aquarium to block the sunlight and measure the mass of the phytoplankton.
B) Change the closed system to isolated, so that energy can move out of it. Then measure the amount of energy that leaves.
C) Measure the mass of the phytoplankton before and after photosynthesis. Add the mass of the water.
D) Measure the amount of energy in the phytoplankton and the amount of light entering the aquarium. Then measure the amount of energy in the phytoplankton after exposure to the light and determine the difference.
E) Measure the amount of energy in the phytoplankton and the amount of light entering the aquarium. Then measure the amount of energy in the phytoplankton after exposure to the light and determine the difference.

Answer 1

Measure the amount of energy in the phytoplankton and the amount of light entering the aquarium. Then measure the amount of energy in the phytoplankton after exposure to the light and determine the difference.

Explanation:

Phytoplanktons like most of the plants use chlorophyll, sunlight and carbon di-oxide for photosynthesis but it depends on other organisms to consume extra energy as they are unable to gain enough energy from their consumption of light. This differs among the different species of planktons.

It can be observed in an aquarium that a phytoplankton is gaining less energy than the energy they have absorbed by the light and this can be done by measuring the energy before and after the photosynthesis.