Setup Directions
Setup Directions
This experiment essentially begins where Experiment #3 ended. It uses the same poor man's biospheres and the same Pothos plants used in our third study. Hence, the only thing you need to do is refill the 3-liter bottles that held the peas of Experiment #3 with sand (as described in the Setup Directions for our third study), plant your radish seeds in them (as described below), add enough water to the aquarium bases to replace that used for CO2 determinations in Experiment #3, place the 10-gallon aquarium tops on the 10-gallon aquarium bases, seal them together with duct tape, reinsert the silicone air tubing used for siphoning water from the tanks for CO2 testing, make the appropriate air exchange holes in the duct tape, and top the units off with the two strip-lights used in Experiment #3.
Because radishes are typically much smaller than pea plants, we are planting two seeds in each of our 3-liter bottles, as opposed to the one seed per bottle in our pea experiment. These seeds are separated from each other by about five centimeters and are placed 1.5 cm deep in pencil-point holes that fall on a line running through the centers of the 3-liter bottles that is oriented parallel to the front glass panels of the aquariums.
When all of these steps are completed, the experiment has begun. Check the units each day for seedling emergence; and when all have sprouted, begin your airspace CO2 concentration measurements as described in our CO2 Measurement Technique section. Again, we typically make these determinations every Monday, Wednesday and Friday.