Question

sophia is conducting an investigation on mechanical weathering using the freeze - thaw cycle. what is the best way for her to ensure accurate results? add varying amounts of water to each rock in the experiment. measure the mass of the rocks before and after each cycle. skip recording observations if no visible changes appear. change the rock type halfway to observe different outcomes.

Explanation:

To ensure accurate results in an experiment on mechanical weathering via the freeze - thaw cycle, one should control variables and record data precisely. Measuring the mass of rocks before and after each cycle allows for quantitative data collection to assess weathering. Adding varying amounts of water (A) changes a variable, skipping observations (C) may miss subtle changes, and changing rock type halfway (D) also changes a key variable.

Answer:

B. Measure the mass of the rocks before and after each cycle.