Final answer:
In the provided investigation, the dependent variable is the number of pennies the aluminum foil boat can hold while floating.
Step-by-step explanation:
The dependent variable in this investigation is the number of pennies that the boat can hold while floating. This variable is dependent because it will change based on the variable that is being tested, which can be the design or shape of the boat. The objective of the experiment is to determine the boat design that will hold the greatest number of pennies, therefore the success of the boat is measured by the number of pennies it can support without sinking.