Hey!
To approach this essay, you need to understand what "mastery of nature" means. Im assuming (by the succeeding phrase "slaves of the machine") that mastery of nature refers to our quest to conquer the elements here on Earth (drilling for nonrenewable oils, mining precious jewels, destroying rainforests for resources, etc.)
Since this is a short essay, I would find/use those three things in reference to such! These all need to be clearly defined in your introductory paragraph, with a concluding statement at the end stating how these have made us "slaves to the machine," or in bondage to the continuity of these systems.
You will need supporting paragraphs that talk about each point (4 - 6 sentences). And then a conclusion paragraph summing everything up. This will easily put you at a page or more!
Hope this helps!
