Other sciences build upon physics. Physicists conduct research into the fundamental laws of nature or make use of what we already know about the physical world to design and develop new practical products. As a career, physics offers an astonishing variety of possibilities. The world of the physicist stretches from the tiniest particles of subatomic matter to galaxies and beyond. It includes computer circuitry and spacecraft orbits, medical imaging and the search for controlled fusion power.
Most modern technology rests on physics.
Sometimes new knowledge is put to work quickly. For example, many practical uses were found for the laser soon after its invention. Sometimes new knowledge is slow to be harnessed. In 1905 Albert Einstein explained how light can eject electrons from solid surfaces. Physics provides deep understanding of the laws of nature and will continue to help shape the world of the future.