Some of the great unanswered questions in science are often the simplest and most familiar. What is the nature of consciousness; how did the universe begin and why is there life on Earth; are all examples. Here is another that has long puzzled scientists: is a hotdog a sandwich?
Now Madelyn Leembruggen and Caroline Martin at Harvard University in Cambridge say they have solved this question thanks to an approach based on the statistical physics of phase transitions. “To remove any of the reader’s lingering uncertainty: yes, a hotdog is a sandwich,” they conclude.
At the heart of their work is the classification of food in three categories or phases: soup, salad and sandwich. They then explore the transitions from one phase to another to construct a complete phase diagram. “We fully map out the phase space of the soup-salad-sandwich (Triple S) transitions,” say the researchers.
They distinguish between soups and salads based on pore size and the penetration depth of the embedding matrix. “If the bulkiest components of the dish form a scaffold, then the ability of the remaining ingredients to efficiently permeate this scaffold determines the phase of the dish,” say Leembruggen and Martin.
For example, an identical set of ingredients can exist as a chunky salad, a salsa or gazpacho, depending on how finely they are diced. This demonstrates a complete transition from salad phase to soup phase.
