Question

A scientist wants to test whether the pH, salinity, and temperature of seawater impacts coral development. He sets up an experiment with three conditions: Aquarium 1: Normal pH, normal salinity, normal temperature Aquarium 2: High pH, high salinity, high temperature Aquarium 3: Low pH, low salinity, low temperature He finds that coral grow the least in Aquarium 2. He concludes that coral does not grow well in conditions with high salt. Why is this an invalid conclusion?

Answer 1

He was testing more than one variable in the aquarium which would change the outcome of the experiment. it could have been the Ph levels or the temperature of the water.

Answer 2

In the given experiment, the scientist is checking for the effect of more than one variable on the development of the coral, which includes the pH, the salinity, and the temperature. The conclusion that the coral do not grow in the water with high salinity is wrong as in that aquarium, the pH, and the temperature were also high. They could also have been the factors behind the decreased growth of the corals. One variable should be tested at a single time to arrive at a valid conclusion.