Is it everything (a noun) or is it "to discover" (a verb)? I think you should revise that intro so that it does not seem to refer to both a noun and a verb. Then again, maybe you should state that science can be thought of as something that is done or as a body of knowledge, in which case it is something you do and also a noun...
Okay, this is not bad, but it is a little bit simplistic. I think it will be better if you come up with one great observation and write the whole essay as support for that observation, that theme.
I'll choose my favorite observation from your essay:
Whether the discovery is 200 years old, 100 years old or present, it's science nonetheless.
I think you should write this as your thesis statement, and then write 3 body paragraphs. Make each body paragraph about a different idea related to this observation.
Here is an example of a body paragraph to support that thesis statement:
One way of seeing how science has different forms at different times is to consider the word technology. In modern times we do not think of a pencil as a piece of technology. Nowadays, the word technology refers to things like ipads and robots. But there was a time when a pencil was advanced scientific technology.
Write body paragraphs that support one main idea, which will be your theme.
:-)