There are a variety of ways to use evidence. Young children may make conclusions that are only slightly related to available evidence. Older children may use evidence in more sophisticated ways, including recognizing patterns of data from which to extrapolate or interpolate. The greater the use of evidence to link the original ideas to future behaviors, the more useful and testable the prediction. It is important to know how to gather evidence and how it can be used to best advantage.
Predictions invite the orderly gathering of evidence for a specific purpose.
With meaningful evidence, we can answer a question or test a prediction with some certainty that the appropriate variable is being tested and systematically measured. This means the investigator is able to understand which variable will be held constant and which will be undergoing change, a concept that is often difficult for the young or inexperienced investigator. An investigation typically takes many unanticipated twists and turns. Solving one problem may lead to another, so investigations may take many different paths. Our kindergartners experienced this as they planned their own potato investigations.