Katherine wanted to determine which of several popular herbicides was most effective on weeds. She grew five flats of 100 grass seeds each for 5 days. She then took each of five herbicides and sprayed the same amount on each flat. Each flat received the same amount of water and sunlight. She observed the flats at the end of 12, 24, 36, and 48 hours and counted how many plants in each flat died within the various time periods.

What are the independent and dependent variables, and what is the control?

the independent variables: those modified by the researcher during the experiments. In this case, the kind of herbicide and the time are variables changes in the study by the researcher.

the dependent variables: those which are not controlled directly by the researcher but are impacted by the changes of the independent variables. In this case, the amount of plant that died.

The control variables: are constant elements in the research, in this case the amount of waters, the amount of sprayed herbicide are constant, so the study never try to understand how a change of this variables affect impact the experiment.

Muskan2024 Muskan2024 · Answer 2 · 2025-01-11T05:37:43-05:00

The independent variable in Katherine's experiment is the type of herbicide, the dependent variable is the number of plants that died, and the control would be flat with no herbicide applied.

In Katherine's experiment, the independent variable is the type of herbicide used on each flat of grass seeds, as this is the variable being changed to test its effect on weed elimination.

The dependent variable is the number of plants that died in each flat within the various time periods, which depends on the effect of the herbicide.

The control could be a sixth flat where no herbicide is applied, maintaining the same conditions of water and sunlight, to compare the efficacy of the herbicides against natural conditions.