Question

that the oil floated to the top of the container after it had sat untouched for a while. he wondered, \could a thick enough oil layer prevent the water from evaporating?\ he guessed that the thicker the oil layer was, the less water would evaporate because the oil would act as a barrier and stop water molecules from escaping into the air. devin set up nine identical cups and filled each one with an equal amount of water. in the first three cups, he added a thin layer of vegetable oil, just enough to cover the surface. in the next three cups, he added a thicker layer of oil. he did not add any oil to the remaining cups. he left them all on the counter for three days. then devin measured the water level in each cup and calculated the average for each group. he found that the water level was the lowest in the cup with no oil and the highest in the cup with a thick layer of oil. he concluded that a thicker layer of oil does indeed reduce water evaporation more effectively than a thin layer. submit next up done for now? try these next: identify control and experimental groups identify independent and dependent variables identify the experimental question identify questions that can be investigated with a set

Explanation:

The experiment studies the effect of oil - layer thickness on water evaporation. The control group is the cups with no oil, and the experimental groups are the cups with thin and thick oil layers. The independent variable is the thickness of the oil layer (none, thin, thick), and the dependent variable is the water - level change (related to evaporation). The experimental question is "Could a thick enough oil layer prevent the water from evaporating?".

Answer:

Control group: Cups with no oil.
Experimental groups: Cups with thin oil layer, Cups with thick oil layer.
Independent variable: Thickness of oil layer.
Dependent variable: Water - level in the cup.
Experimental question: Could a thick enough oil layer prevent the water from evaporating?