Science Reasoning Flashcards

In a controlled experiment, the variable that the researcher deliberately changes is called the:

Answer: Independent variable

The independent variable is intentionally manipulated by the researcher to observe its effect on the dependent variable.

A student notices that plants near a window grow faster than those in a dark corner. What is the most reasonable hypothesis?

Answer: Light exposure increases plant growth rate.

Since the observed difference relates to proximity to a light source, the most direct hypothesis involves light exposure.

A graph shows that as temperature increases, enzyme activity first rises then falls sharply. What can be concluded?

Answer: Enzymes have an optimal temperature range beyond which they denature.

Enzymes function best within an optimal temperature range; excessive heat disrupts their structure (denaturation).

Which of the following best describes a scientific theory?

Answer: A well-substantiated explanation supported by extensive evidence

A scientific theory is a rigorously tested explanation supported by a large body of evidence, not merely a guess.

In an experiment, results that support the null hypothesis mean:

Answer: No significant effect was found between variables.

Supporting the null hypothesis means the data showed no statistically significant relationship between the variables tested.

A researcher tests whether caffeine affects reaction time by giving one group coffee and another group water. The group given water is the:

Answer: Control group

The control group receives no treatment (or a placebo) to serve as a baseline comparison for the experimental group.