Scientific breakthroughs happen when a Sim who works in the science career does something that inspires them. Some interactions, such as reading a book, using a microscope, or tinkering will have a light bulb next to them. When Sims do the interaction a light bulb appears above their head and when it is lit up the Sim will have a breakthrough shouting "euronka!" at the new discovery. There are four levels to a scientific breakthrough: 25%, 50%, 75% and 100%. When a Sim is focused they will receive a scientific breakthrough much faster.