The results This is the graph show the life, and death, of the two batteries. You will find some of the following questions easier if you put these results into your data logging software. For other ideas and clues about what you need, see the Battery logging experiment. Looking at the results I can't remember which battery is which. They say that alkaline batteries work for longer and then fade away quickly.
Zinc batteries work for less time and fade away steadily.
The alkaline battery cost three times as much as the zinc battery. Use the information you have to calculate which battery offers the better deal. It seems that one of the batteries isn't very good. What you might try to find out Single cells come in several different sizes - A cells, AA cells, AAA cells. In my experiment I used light sensors but you might instead have used voltage sensors.