Assumptions and Hypothoses
- Have all students make assumptions before any experiment begins and form a hypothesis. These assumptions could include predicting which brand will dissolve fastest or whether single-ply tissue will dissolve faster than double-ply. Make a chart that visually compares how many students predict each possible outcome and discuss why or why not the predictions came true. This is a valuable way to teach the scientific method — and introduce an element of competition into the experiment. It will also help students investigate their underlying assumptions and what may have made them guess incorrectly.
- After deciding on a specific experiment, develop a procedure that will prove or disprove the assumption and will apply to all variables. Decide what to use to dissolve the paper, how long to allow it to remain in the substance, what other actions should be taken, how the results should be measured, and how those measurements should be compared. For instance, the class could choose to soak one-half ounce of paper in one cup of water for 30 minutes, stir each cup five times at the beginning and end of the 30 minutes, pour the result through a strainer, then weigh the remaining fiber, if any. A chart could then display and compare the resultant amounts of fiber.
- Introduce variables to add interest to the experiment. In this case, this could mean competing brands of toilet paper, private label compared to national brands, two-ply versus single-ply, warm water and cold water, and variations in stirring length and strength. Have the students research the topic and suggest variables that will result in meaningful or interesting results. Change only one variable per experiment to ensure a fair and uniform result.
- Chart all results and have students write short reports about their conclusions from those results. Topics might include accuracy of advertising claims, variation in cellulose content by brand, degrees of biodegradability and price/performance comparisons.