Science/Strand IV/Content Standard 2/High School/Benchmark 4
Benchmark Question: How does matter change?
Focus Question: How does energy get transformed in a
Working in small lab groups,
students will observe photosynthesis in green plants by performing the
1. Place a sprig of a submerged aquatic plant (e.g., Elodea
anacharis) in a
small test tube.
2. Fill the test tube with water and place inverted into
a beaker filled with water. The test tube should still be completely filled
3. Repeat steps one and two for a second test tube.
4. Shine a bright light source on one set-up (e.g.,
lamp, sunlight) and place the other in a dark location. Let both stand for
at least half an hour.
Observe the plants in both
test tubes. Small bubbles of oxygen (from photosynthesis in the plant)
should be filling the top of the test tube under the bright light, while
the one in the dark has few or no bubbles. Students will analyze the
results of the experiment and discuss the source of energy required to
produce the gas. Using references, each student will diagram the energy
transformation in photosynthesis. Each student will write an explanation of
the energy transformation in photosynthesis, including the fact that light
energy is absorbed and used by photosynthesis to produce the bubbles of