When did science begin?

Here is a philosophical answers: technically, science began the day the very first humans looked at the sky or ocean and wondered why it was blue, or understood that fire cooks food....what i mean is, science is pretty much the all inclusive study of everything everywhere in order to seek out an explanation for why things are the way they are...so in reality, it began the first time someone wondered how/why anything is the way it is.

Science is an intellectual activity carried on by humans that is designed to discover information about the natural world in which humans live and to discover the ways in which this information can be organized into meaningful patterns. A primary aim of science is to collect facts (data). An ultimate purpose of science is to discern the order that exists between and amongst the various facts.

Science involves more than the gaining of knowledge. It is the systematic and organized inquiry into the natural world and its phenomena. Science is about gaining a deeper and often useful understanding of the world.