ACT (Enhanced)ScienceMedium
A group of students is designing an experiment to investigate how the concentration of a sugar solution affects the rate of fermentation by yeast. They plan to prepare four different sugar solutions (5%, 10%, 15%, and 20% sugar by mass). For each solution, they will add a fixed amount of yeast and incubate the mixtures at a constant temperature. They decide to measure the volume of carbon dioxide gas produced over 30 minutes as an indicator of the fermentation rate. Which of the following would be the most effective way to ensure the reliability of their results?
- AConducting only one trial for each sugar concentration to save time and resources.
- BRepeating the experiment multiple times (e.g., three trials) for each sugar concentration.
- CVarying the incubation temperature for each concentration to see the temperature effect.
- DUsing a different type of yeast for each sugar concentration to observe varied responses.
Show answer & explanationAnswer & explanation
Correct answer: B. Repeating the experiment multiple times (e.g., three trials) for each sugar concentration.
Repeating an experiment multiple times (conducting multiple trials) for each condition is crucial for reliability. It helps to minimize the impact of random errors, identify inconsistencies, and ensure that the observed results are consistent and not due to chance. The results can then be averaged to provide a more accurate measurement.
Why the other options are wrong
- A. Conducting only one trial significantly reduces reliability, making it impossible to assess consistency or account for random errors.
- C. Varying incubation temperature would introduce another independent variable, making it impossible to determine if changes in fermentation rate are due to sugar concentration or temperature.
- D. Using different yeast types would introduce another variable, confounding the results and making it impossible to isolate the effect of sugar concentration.
Experimental Reliability
The consistency or repeatability of an experiment's results. A reliable experiment will produce the same or very similar results if repeated under the same conditions.
- Achieved through multiple trials and consistent procedures.
- Reduces the impact of random errors.
- Ensures that results are not due to chance.
Memory trick: Reliability Repeats, Validity Controls