Trish's Experiment Trish wondered if salted water would boil faster than unsalted water. She filled a pan with one liter of plain water and heated it. Trish recorded how much time it took for the water to boil. Then Trish emptied the pan and cooled it to room temperature. She filled the pan with one liter of water and two tablespoons of salt. Using the same heat setting, Trish heated the water until it boiled, and she recorded the time.
31. What is the control in Trish's experiment? (Remember, the control is the thing that does not receive the experimental treatment.) (1)
a. heat b. salted water
c. a timer
d. plain water
32. What is the independent variable (the thing that changes) in Trish's experiment? (1)
a. boiling
b. salt
c. heat
d. time
33. What is a constant (does not change) in Trish's experiment? (1)
a. level of heat
b. amount of water
c. type of pan
d. all of the above