Physics is the study of the relationship between matter and energy. As with other professions, there are many specializations. For example, acoustics is the study of sound's physical properties. Physicists working in acoustics work on applications such as SONAR, music, ultrasound technology and noise-reduction technology. Geophysicists investigate how the principles of physics apply to the earth, such as understanding the physics of earthquakes. Nuclear physicists study the relationship between atomic particles and work on harnessing their power. Nuclear physicists work in fields such as radiation therapy and power production.
Physicists with PhD's can become university professors, educating scientists and non-scientists alike. According to physicist Dr. Michio Kaku, potential physics professors may face problems such as job scarcity and years of struggle while gaining a permanent position. However, Dr. Kaku believes that one of the major advantages of working at a university rather than a private company is that college professors can work on any project they want to when they aren't teaching.
Applied physics involves solving real-world problems with the principles of physics. For example, physicists help manufacturers develop better manufacturing processes for the research and develop new products. Medical physicists help create new techniques and tools for investigating the body and treating diseases. For instance, physicists helped create tools such as x-ray machines, computed axial tomography (CAT) scans, positron emission tomography (PET) scans and magnetic resonance imaging (MRI). Some physicists are what "Radiations" magazine calls "hidden physicists" who work in occupations not normally associated with physics, such as police work, public policy, government and law.
Many physicists add to the body of human knowledge by exploring the mysteries of the universe. Astrophysicists probe the principles that drive the cosmos as they examine stars, galaxies, high-energy particles, gravitational fields and other astronomical phenomena. Space research also has many practical applications, such as weather satellites, communications satellites and navigation technology. Particle physicists study the tiny, indestructible particles that act as the building blocks of all matter. Plasma physicists examine the properties of plasma, the fourth state of matter found in stars. Understanding plasma may help scientists develop nuclear fusion as a source of energy.
Global climate change, depletion of the ozone layer and other environmental problems are major concerns. Studying and protecting the environment isn't just for ecologists. Environmental physicists apply physics principles to studying factors that impact the water, air and land. They have played many important roles in developing and managing alternate sources of energy, monitoring and cleaning up pollution and creating efficient recycling techniques.