Scientific knowledge may be open to change because our human knowledge is limited. Discoveries are made all the time opening up explanations to things that contradict what we previously thought to be true. Because of this, we have come to be open to change scientific knowledge in case new information is discovered that can shed light on the unknown.
Take our solar system for example. We know our solar system to be heliocentric, meaning that our sun is the center of it. Used to, the geocentric model of our solar system was widely accepted that the Earth was the center of the solar system.
Even the theory that Earth used to be flat. Once we had technology to take pictures from space and prove for sure that the earth is round, some people believed that it was flat.
I hope this helped! Have an amazing day :)