Final answer:
For the student's experiment on popcorn brands, the correct options are that the independent variable is the different popcorn brands, and the dependent variable is the number of popped kernels after 3 minutes in the microwave. The microwave and the time are constants to ensure a fair test. So, the best answer is a, Independent Variable (IV): Different popcorn brands.
Step-by-step explanation:
Identifying Variables in a Scientific Experiment
In the scenario where a student is testing which brand of popcorn has the most popped kernels after 3 minutes in the microwave, the correct identification of variables is as follows:
Independent Variable (IV): Different popcorn brands - This is the variable that is changed by the researcher to observe its effect on the outcome.
Dependent Variable (DV): Number of popped kernels - This is the variable that is being measured or observed, and it changes in response to the independent variable.
Constant: Microwave, time (3 minutes) - These are the conditions that are kept the same throughout the experiment to ensure that the results are due to the independent variable alone.
Using these definitions, option a is correct. The independent variable is the different popcorn brands, and the dependent variable is the number of popped kernels. The constants in the experiment would be the microwave in which the popcorn is popped and the time allowed for popping (3 minutes), as these remain unchanged for each popcorn brand being tested.
Knowing the correct identification of independent and dependent variables is crucial in setting up a valid experiment as it allows to establish the cause-and-effect relationship.
So, the best answer is a, Independent Variable (IV): Different popcorn brands.