what is the essential feature of science that makes it different from other ways of understanding the world?

Observation and Experimentation

Scientific methods were developed in order to understand the world and the universe through observation and experimentation.

Most of the early scientists where devout theologians. They used observation and experimentation to prove or disprove religious dogma or traditions passed down through the generations.

Science was a way that others could look at your work or your conclusions and either duplicate them or disprove them and over the centuries it has evolved from simple observations and documentation, sometimes massively wrong, to complex experiments and monotonous scrutiny.

However, without religion we might still be in the dark ages. If no one had ever laid down the first theory of the formation of the earth and the heavens, no one would have had a chance to dispute it using science.

The fundamental core of science is that beliefs are held to be tenuous, based on the amount of supporting evidence and the lack of contrary evidence. That is, a scientist knows that he can always be wrong if a new experiment shows data contrary to his mental model of the world. Science shuns faith, which is belief without physical evidence or, even more difficult, belief in the face of contrary evidence.

Working on bio lab on labor day. Nice. The second guy seems to know what the answer is.

the essential feature is "experiments"

its self correcting nature. in science if you can demonstrate that something is wrong, its wrong. in religion demonstrating such a thing would lead to either childish denial or even physical punishment.