One of the most promising ways to understand the origin and evolution of structures (galaxies and their clusters) in the universe is to observe its hydrogen through an electromagnetic radiation of 21 cm wavelength. This observation is still in its infancy, but scientists have developed various tools for simulating the hydrogen using the theoretical models of cosmology and astrophysics. In this project, we will use one such tool, 21cmFAST, to simulate the brightness temperature of cosmic hydrogen at different epochs in the history of the universe. We will then measure different types of power spectra of this brightness and, finally, analyze the effects of the theoretical models on the power spectra. Understanding these effects are important because they pave the way for verifying different hypotheses about the evolution of the universe.