"You run out of brown sugar and decide to use only granulated sugar instead. The cookies come out much thinner than usual. Design a controlled experiment to test your hypothesis *, describing how you would interpret your results. Please limit your response to one paragraph."

My hypothesis is that without the brown sugar would be fewer components (present in brown sugar) that contribute to the cookie growth. Perhaps due to reaction with the baking soda... brown sugar acids releases? How I make a experiment to test this? :(

How about 1 batch made with brown sugar only, another batch with 3/4 brown and 1/4 granulated, another batch with 1/2 and 1/2, another batch with 1/4 brown and 3/4 granulated and a final batch with all granulated. Then compare the cookies.

To test your hypothesis, you can design a controlled experiment by baking two batches of cookies. One batch will use only granulated sugar, while the other batch will use a mixture of granulated and brown sugar, as per your usual recipe. Keep all other ingredients and baking conditions the same. Measure the thickness of the cookies once they have cooled down. If your hypothesis is correct, the cookies made with only granulated sugar should be thinner compared to the batch with a mixture of sugars. To interpret your results, compare the thickness measurements of the two batches using statistical analysis, such as a t-test, to determine if there is a significant difference between the groups. If there is a significant difference, it would support your hypothesis that the absence of components in brown sugar affects the cookie growth.