The distinction between science, engineering, and technology is not always clear. Science is systematic knowledge of the physical or material world gained through observation and experimentation.

Engineering is the goal-oriented process of designing and making tools and systems to exploit natural phenomena for practical human means, often (but not always) using results and techniques from science. The development of technology may draw upon many fields of knowledge, including scientific, engineering, mathematical, linguistic, and historical knowledge, to achieve some practical result.

Technology is often a consequence of science and engineering, although technology as a human activity precedes the two fields. For example, science might study the flow of electrons in electrical conductors by using already-existing tools and knowledge. This new-found knowledge may then be used by engineers to create new tools and machines such as semiconductors, computers, and other forms of advanced technology. In this sense, scientists and engineers may both be considered technologists; the three fields are often considered as one for the purposes of research and reference.

The use of tools by early humans was partly a process of discovery and of evolution. Early humans evolved from a species of foraging hominids which were already bipedal,

Hominids started using primitive stone tools millions of years ago. The earliest stone tools were little more than a fractured rock, but approximately 75,000 years ago,pressure flaking provided a way to make much finer work.

Other technological advances made during the Paleolithic era were clothing and shelter; the adoption of both technologies cannot be dated exactly, but they were a key to humanity’s progress. As the Paleolithic era progressed, dwellings became more sophisticated and more elaborate; as early as 380 ka, humans were constructing temporary wood huts. Clothing, adapted from the fur and hides of hunted animals, helped humanity expand into colder regions; humans began to migrate
out of Africa by 200 ka and into other continents such as Eurasia.