Why must science be open to change?

 everything in science is all based off of  a theory because there isn't enough evidence to prove it to be a fact. So,if more evidence is discovered to prove it,a theory will become a factual,or if evidence is discovered  against it, aka disproving it  a theory, the theory is no longer even valid as a theory because theres factual evidence against it. so, knowing this scientists have to be open to new ideas in order to find out the "truth" or to build upon.

Iwould think it is temperature, silica, oxides (gases)