Four friends were in the grocery store and they wondered which freezer is better at keeping the food cold; an upright freezer with a door or a deep freezer without a lid? Read the following explanations and decide which person you agree with. a: Theresa: “The upright freezers are more efficient because they have doors to keep the convection currents circulating.” b: Kristen: “Actually the deep freezer has a thick layer of ice on the sides for an insulator and when you reach to the bottom things feel colder.” c: Brianna: “I think it is the deep freezer because the cold air stays in the bottom because cold air is denser.” d: Aaron: “The upright freezer is better because it keeps the cold air in. I have seen the cold air fall out when I open the freezer door.”