Alysha wants to test the effect of different materials on the melting rate of ice. She finds the initial mass of four pieces of ice. She then covers three pieces with either tinfoil, wool cloth, or paper. The fourth piece is left uncovered.

After 30 minutes, Alysha calculates the final mass of each piece of ice to determine which melted the fastest.

What is the dependent variable in this experiment?

Juan notices that water appears to evaporate from his 30 gallon saltwater aquarium faster than from his 30 gallon freshwater aquarium.  Juan wants to know if his observation is true.  At what point is Juan at in the scientific method?

Kim’s experiment showed that chicken eggshells were stronger when she gave the hen feed, to which extra calcium had been added.  At what point is Kim at in the scientific method?

Alysha wants to test the effect of different materials on the melting rate of ice. She finds the initial mass of four pieces of ice. She then covers three pieces with either tinfoil, wool cloth, or paper. The fourth piece is left uncovered.

After 30 minutes, Alysha calculates the final mass of each piece of ice to determine which melted the fastest.

What would be an appropriate hypothesis for this experiment?

Richard was observing black swallowtail butterflies in the field.  Which one of these is an observation he made about a black swallowtail butterfly?