Why does the cookie’s cream stick to just one wafer when twisted apart? The answer could be a groundbreaking discovery for 3D printing and flexible electronics.
When you twist an Oreo cookie open to get to the creamy middle, you’re simulating a basic rheology test, which examines how a non-Newtonian substance flows when twisted, crushed, or otherwise strained. In search of an answer, the team put cookies through normal rheology experiments in the lab and discovered that, regardless of the flavour or quantity of stuffing, the cream in the middle of an Oreo virtually always adheres to one wafer when twisted open. The cream occasionally separates more evenly between both wafers in earlier boxes of cookies.
The team’s research is an opportunity to make rheology science more accessible to the general public. To that goal, the researchers created a 3D-printable “Oreometer” – a simple gadget that firmly grasps an Oreo cookie and controls the twisting force that gradually twists the cookie open using pennies and rubber bands.