The investigator never begins an experiment without a prediction of its outcome. The prediction is always based on the particular experiment designed to test a specific hypothesis. Predictions are written in the form of if/then statements: "lf the hypothesis is true, then the results of the experiment will beâÂÂŚ"; for example, "if cactus spines reduce herbivory, then removal of the spines will result in greater surface area removed by herbivores." Making a prediction provides a critical analysis of the experimental design. If the predictions are not clear, the procedure can be modified before beginning the experiment. For the soybean experiment, the hypothesis was: "Exposure to sulfur dioxide reduces reproduction." What should the prediction be? State your prediction.
To evaluate the results of the experiment, the investigator always returns to the prediction. If the results match the prediction, then the hypothesis is supported. If the results do not match the prediction, then the hypothesis is falsified. Either way, the scientist has increased knowledge of the process being studied. Many times the falsification of a hypothesis can provide more information than confirmation does, since the ideas and data must be critically evaluated in light of new information. In the soybean experiment, the scientist may learn that the prediction is true (sulfur dioxide does reduce reproduction at the concentration tested). As a next step, the scientist may now wish to identify the particular level at which the effect is first demonstrated. Review your hypotheses for the numbered questions. Consider how you might design an experiment to test the first hypothesis. For example, you might measure auditory function by performing hearing tests or observing changes in structures in the ear. The prediction might be:
IF cell phone usage reduces auditory function (a restatement of the hypothesis),
then people who use cell phones will score lower on hearing tests than persons who do not (predicting the results from the experiment).
Now consider an experiment you might design to test the second hypothesis. How will you measure "mental advantage"?
State a prediction for this hypothesis and experiment. Use the if/then format:
The actual test of the prediction is one of the great moments in research. No matter the results, the scientist is not just following a procedure but truly testing a creative explanation derived from an interesting question.âÂÂ
1. Honeybees provide 80% of the pollination services for crops, including almonds, squash, melons, alfalfa, apples, and pumpkins. Migratory beekeepers transport over 2 million hives to farmland as crops begin to flower. In 2006-2007 beekeepers were alarmed when 50% of the honeybee colonies in 26 states were lost. In fact one of the biggest mysteries was that the bees were not found dead in the hives, but rather were simply gone! Scientists have termed this Colony Collapse Disorder (CCD). They are currently considering three alternative hypotheses: emerging pathogens (viruses, bacteria, and/or fungi), environmental toxins or chemicals; or abduction by humans (or aliens). Using the criteria in Lab Study B, Developing Hypotheses, select the hypothesis you would pursue as a scientist and justify your choice.
