You run out of brown sugar and decide to use 1.5 cups granulated sugar instead. The cookies come out much thinner than usual. Formulate a one-sentence hypothesis for why the recipe failed.
The brown sugar contained a substance that made the cookies have more bulk.
I.e. a testable hypothesis, not necessarily accurate, describing why white sugar may not be an effective substitute for brown sugar. Example full credit answer: "Cookies made without brown sugar fail to rise because the brown sugar contributes acid, which reacts with the baking soda to produce gas for leavening."
The hypothesis for why the cookies came out much thinner than usual when using 1.5 cups of granulated sugar instead of brown sugar could be that the moisture content and chemical reactions in the recipe were affected, leading to less spreading and denser cookies.
