Question

Four researchers are each conducting an experiment to test whether talking to plants helps them grow faster. Each researcher puts 10 plants in a room, where they are talked to every day, and 10 more in another room where they are not talked to at all. Select the researcher who is applying control variables correctly.

a) Jackie decreases the light levels in one of the rooms to test if that also has an effect on growth.

b) Michael talks to the plants in one room and plays music in the other room to see if both factors influence growth.

c) Emily talks to the plants in one room and waters them more frequently to see if water availability affects growth.

d) Sarah talks to the plants in one room and introduces a fertilizer in the other room to test the combined effect on growth.

Answer 1

None of the researchers are applying control variables correctly as each introduces additional variables, such as different light levels, music, varying amounts of water, or fertilizer, rather than maintaining identical conditions with the sole change being talking to the plants.

Step-by-step explanation:

In a laboratory experiment studying plant growth, the goal is to determine if an independent variable, such as talking to plants or the presence of fertilizer, affects a dependent variable, which in this case is plant growth.

The purpose of a control group is to serve as a baseline to compare the effects of the independent variable on the experimental group. None of the researchers—Jackie, Michael, Emily, or Sarah—are applying control variables correctly since they are all introducing another independent variable in addition to talking to the plants.

The correct way to conduct an experiment is to have a control group that receives no experimental treatment and is kept identical to the experimental group in all other conditions.