At the heart of science is curiosity about the universe in which we live. This is the motivation from which science was born. Curiosity remains the driving motivation behind it today.
Because we are sentient and somewhat intelligent creatures, many of us follow our curiosities with further observation. As children we learned/evolved to explore our world, test our bodies, and learn how best to navigate our surroundings. This process, especially the curiosity part of it, was critical to the proper developments of our bodies, our neurons, our muscles, our coordination, and the learned abilities to walk, talk, and think clearly.