Final answer:
In the experiment involving the phase change of water, the independent variable is the time, and the dependent variable is the temperature of water. The experiment aims to determine how long it takes for ice to melt and for water to boil, while controlling other variables for accurate results.
Step-by-step explanation:
The independent variable for the experiment studying water's phase change properties is the amount of time, which is what the scientist is manipulating. In contrast, the dependent variable is the temperature of water, as it changes in response to time and indicates when the phase changes occur. Plotting this data on a graph where time is on the x-axis and temperature is on the y-axis will show how long it takes for the ice to melt and the water to boil. It should be noted that the temperature remains constant during the phase change due to the energy absorbed in breaking intermolecular forces rather than increasing the kinetic energy of the molecules.
During the experiment, other variables should be controlled to ensure a valid comparison between the melting and boiling times. These may include the amount of ice and water used, the initial temperature of the ice and water, and the conditions of the surrounding environment.
Review of Variables
An experiment is a procedure carried out to support or refute a hypothesis or to discover new insights. In the given example, the dependent variable is the number of bacteria on each type of gel as it depends on the independent variable, which is the type of gel used.