While World War I was the first war in which science played a major role in warfare and armaments, the increase in military funding of science following the second World War was on a scale wholly unprecedented. World War II has often been called "the physicists' war" for the role that those scientists played in the development of new weapons and tools, notably the proximity fuze, radar, and the atomic bomb. The bulk of these last two activities took place in a new form of research facility: the government-sponsored laboratory, employing thousands of technicians and scientists, managed by universities (in this case, the University of California and the Massachusetts Institute of Technology).

In the shadow of the first atomic weapons, the importance of a strong scientific research establishment was apparent to any country wishing to have a role in international politics. After the success of the Manhattan Project, a scientific and technological endeavor on an unprecedented scale, governments became the chief patron of science, and the character of the scientific establishment underwent several key changes. This was especially marked in the United States and the Soviet Union during the Cold War, but also to a lesser extent in many other countries.

"Big Science" usually implies, and gets its "big-ness" from, these specific characteristics:

• Big budgets: No longer required to rely on philanthropy or industry, scientists were able to use budgets on an unprecedented scale for basic research.
• Big staffs: Similarly, the number of practitioners of science on any one project grew as well, creating difficulty, and often controversy, in the assignment of credit for scientific discoveries (the Nobel Prize system, for example, allows awarding only three individuals in any one topic per year, based on a 19th-century model of the scientific enterprise).
• Big machines: Ernest Lawrence's cyclotron at his Radiation Laboratory in particular ushered in an era of massive machines (requiring massive staffs and budgets) as the tools of basic scientific research. The use of many machines, such as the many sequencers used during the Human Genome Project, might also fall under this definition.
• Big laboratories: Because of the increase in cost to do basic science (with the increase of large machines), centralization of scientific research in large laboratories (such as Lawrence Berkeley National Laboratory or CERN) has become a cost-effective strategy, though questions over facility access have become prevalent.

Towards the end of the 20th century, not only projects in basic physics and astronomy, but also in life sciences became big sciences, such as the massive project involved in the sequencing of the human genome. The heavy investment of government and industrial interests into academic science has also blurred the line between public and private research, where entire academic departments, even at public universities, are often financed by private companies. Not all Big Science is related to the military concerns which were at its origins.

The era of Big Science has provoked criticism that it undermines the basic principles of the scientific method. Results of experiments which require massive and unique machines like particle accelerators are often difficult to verify. Access to scientific facilities is often limited to those who are already accomplished, leading to charges of elitism. And increased government funding has often meant increased military funding; which some claim subverts the Enlightenment-era ideal of science as a pure quest for knowledge. Many scientists also complain that the requirement for increased funding makes a large part of the scientific activity filling out grant requests and other budgetary bureaucratic activity, and the intense connections between academic, governmental, and industrial interests have raised the question of whether scientists can be completely objective when their research contradicts the interests and intentions of their benefactors.

Big Science | Sains Besar | 大科学