Photosynthesis Carbon Dioxide Activity

Sadly, we were not able to acquire our own results during this investigation because the we were not able to observe much/any change in our specimens within the experiment. However, we were able to use previously found data from the same experiment to draw some conclusions. The jar directly under the lamp was dark purple, the jar being shaded from direct light was orange/red, and the jar placed in the cupboard was yellow.

These observations all make sense given what we know about photosynthesis. Photosynthesis happens at a faster rate when exposed to light; therefore, carbon dioxide was used faster in photosynthesis than it was being replaced during respiration causing the solution to turn a dark purple because the carbon dioxide was being reduced in the indicator. The solution in the jar that was thinly shaded from the light of the lamp turned orange/red because photosynthesis and respiration were happening around the same rate; therefore, the carbon dioxide in the solution was being replaced at the same rate it was being used causing the solution to reach an atmospheric carbon dioxide level. The solution of the jar placed in darkness turned yellow because photosynthesis was not taking place; therefore, no carbon dioxide was being used while respiration was producing more carbon dioxide, causing an increase in the carbon dioxide in the indicator solution.

These observations did very much confirm what we set out to show in this experiment.

The indicator turned yellow when the pondweed was placed in the dark.

We can deduce that the solution turned yellow because there was an increase in the carbon dioxide in the indicator solution. We can also deduce that there was an increase in carbon dioxide in the solution because photosynthesis was not taking place.

In our actual experiment, we think it may have been more beneficial to use a larger amount of pondweed from the very beginning of the experiment. We also think the experiment would have worked better if we had cut an inch down the stem of each piece of pond weed before moving the jars. We also think that using less of the indicator may have sped up the process.

The indicator would become yellow if I blew into it because I would be increasing the carbon dioxide in the solution.

The indicator would become red/orange is the plant were to respire and carry out photosynthesis at the same rate because carbon dioxide would be used at the same rate it would be replaced.

At mid-morning and in the afternoon, respiration and photosynthesis would occur at the same rate.