Question

while watching tv, zack saw an advertisement for a water softener. the ad claimed that water with a high mineral content, or \hard water,\ does not clean dishes and laundry very effectively because the minerals in hard water stick to soap and prevent it from lathering. to test this claim, zack filled nine identical bottles with the same volume of distilled water. he added nothing else to three of the bottles, one teaspoon of mineral - rich epsom salt to each of the next three bottles, and two teaspoons of epsom salt to each of the remaining three bottles. he then added a drop of soap to each bottle and shook each one to make bubbles. finally, he used a ruler to measure how thick the bubble layer was in each bottle. complete the sentence. in this experiment, the thickness of the bubble layer in the bottle was ________. a dependent variable an independent variable

Explanation:

In an experiment, the dependent variable is what is being measured and is affected by the independent variable. Here, Zack is measuring the thickness of the bubble - layer which changes based on the amount of Epsom salt (independent variable). So, the thickness of the bubble - layer depends on the amount of salt added.

Answer:

a dependent variable