We See the World Through Mental Models
One of the scientific theories that were the most successful at being adopted and implemented in practice is the “Germ Theory of Disease”.
This theory is so well-adopted that we usually don't stop to think about it. Still, it informs and guides each and every individual that knows about it multiple times a day.
The Germ Theory states that there are microscopic microorganisms, which are invisible to the naked eye, that invade animals, including humans. These microorganisms, called pathogens, grow, reproduce and self-replicate, often causing disease for the hosting organism.
This is such a simple and effective model: “small organisms I can't see can make me sick”.
Where are those pathogens? In most diseases, they are present in the bodily secretions of contaminated individuals, which informs about the usual hygiene practices we take for granted: washing our hands with soap, showering regularly, wearing a mask, and so on -- all of which are practices with the goal of physically removing possible germs, or of introducing a physical barrier to prevent intrusion and contamination.
The Germ Theory is so well-adopted and well-accepted that it sounds silly to discuss all of this. The burden of a successful theory is being invisible and obvious. Still, there are plenty of other ideas that, while successful in the scientific terms -- being sound and correct, grounded in data, and well-replicated experimentally -- are not as successful at obtaining public understanding and adoption.
Another model that I judge to be very useful is an understanding of compound interest grounded in mathematical exponential growth. In fact, it is interesting how the public attention turned toward “flattening the curve” when the 2019 pandemic hit. This is an example of scientific understanding -- the epidemiological model of infection -- put into concrete terms, and ultimately converted into the actions of an individual.