Reasoning Scientific principles that provide justification serving as a link between a claim and the evidence related to an explanation, a model, a hypothesis or a prediction. They also provide additional support for how the evidence supports the claim. Justification and reasoning allow the evidence to be linked to explanations within the larger scientific world of theories. These explanations are relevant to theories within a discipline and are linked to the discipline and the larger body of knowledge that accumulates through empirical studies that are accepted and reviewed by peers.
Transpiration in plants is controlled by water potential. This change in water potential in leaves causes a gradient by which water can be moved upward. When the water potential of the air was increased by the mist and plastic bag, less water evaporated from the leaves, decreasing the water potential gradient between the root and stem. This decreased the transpiration pull. The fan and floodlight simulated environmental conditions such as wind, heat, and intense light. These conditions increase the amount of water transpired by plants. This in turn increased the water potential gradient causing more water to be pulled through the stem. The control plant should have had normal rates of transpiration.