Students are trying to decide which is better for the environment: glass bottles or aluminum cans. They intend to use a formal method of investigation to determine which container is better. They are going to make a list of pros and cons for using each type of container but first need to do some research. The students need to find out things like how much matter and energy are used to make the bottles and cans. How do you know the students in the above study are acting as scientists?