Physics

Summary 2

Many scientists have discovered the phenomena that describe the laws of physics. One of the earliest and best known among them is Galileo Galilei. He was one of the few scientists of his time to challenge Aristotle's existing theory about the motion of Earth and Sun. After conducting several experiments, Galileo concluded that Earth moved around the Sun and not the other way around. Galileo was well known for his method of inquiry to understand events. His most significant contribution to physics is related to the motion of bodies. He determined that two objects dropped from a height fall at the same speed, regardless of their weights. He also defined the law of pendulums, which was employed to devise the first accurate clocks.

Summary

Summary Physics is the scientific study of matter and energy and how they interact with each other. It's a basic science that deals with motion, forces, energy, heat, waves, electricity and magnetism, and the structure of matter, down to the subatomic level. It forms the base for other branches of science, including chemistry and biology. Physics permeates our daily lives in many ways. Our reliance on technology underscores the importance of physics every day. All of the technologies and gadgets that we use can be traced back to the laws of physics. Some of the many branches of physics are noted here: mechanics - the study of forces and motions of bodies thermodynamics - the physics of heat acoustics - the study of sound and sound waves optics - the study of light electromagnetism - the study of electrical and magnetic fields electronics - the study of the flow of electrons, generally in a circuit quantum mechanics - the study of how matter and energy behave at the molecular, atomic, or nuclear levels

Mechanics

Mechanics is the study of energy and motion for bodies affected by a system of forces. There are four basic forces known in the universe. Two of them, quantum forces and nuclear forces, apply only to nuclear interactions. The other two forces are gravitational and electrical forces. These two forces are the root causes of all the day-to-day physical events we experience. Scientists such as Galileo and Newton were the pioneers of this field, known as classical mechanics. Classical mechanics was the first branch of physics to be discovered. It laid the foundation for all the others.

Electricity and Magnetism

Physics also includes the study of electricity, which is one of the four basic forces of nature. Electricity plays a major role in technology and everyday life. Electrical charges follow the laws of mechanics, but like molecules in a gas, their behavior in large numbers is often more interesting and useful than their individual behavior. Electricity appears in nature in different forms, the most prominent being lightning. It's an extremely flexible form of energy that can be put to many uses. Think of all the different electrical appliances and gadgets we use at home, such as refrigerators, air conditioners, phones, TVs, and light bulbs. In physics, magnetism is the study of the phenomena by which materials exert an attractive or repulsive force on other materials. Electricity and magnetism are fundamentally linked. Electromagnetism is used in many technologies, ranging from motors to CAT scan machines.

How Physics Links to Biology and Chemistry

Physics is a fundamental, or basic, science. It has a close connection with both biology and chemistry. Biology, as we know, is the study of life. Medical students study how different organs function. However, they also need to know the laws of physics to understand body functions. For example, regulation and circulation of body fluids follows the laws of physics governing temperature, pressure, volume, and density. Nerves carry electrical impulses that hold messages to and from the nervous system. These impulses follow the laws of physics, as do our body's organ systems. Physics and chemistry are linked too. The discovery of elements and their atomic structure is closely related to physics. In fact, the theory of atoms was largely developed through experiments in atomic and nuclear physics. Quantum mechanics ultimately explains how elements combine to form compounds. Physics also explains gas laws, chemical energy changes, the shape of a molecule, and the kinds of bonds formed between atoms.

What is Physics

Physics is one of the three main fields of science, the other two being biology and chemistry. If asked what biology or chemistry deals with, most of us can come up with a one-word answer: life and chemicals, respectively. But to answer what physics deals with, you may come up with a long list that includes motion, magnets, machines, light, sound, and electrical circuits. What common thread runs through this list? Everything on it makes up part of our physical world. Physics is the scientific study of matter and energy and their interactions. It's a basic science that deals with motion, electricity, energy, heat, sound, light, atoms, nuclear physics, and astronomy, among other topics. These areas of study can be broadly classified under two fields: classical physics and modern physics. Classical physics includes the study of motion, electricity, energy, heat, sound, light, and magnetism. Modern physics deals with topics such as nuclear physics, atomic physics, astrophysics, and relativity. Let's take a closer look at some fields within the discipline of physics.

Quantum and Nuclear Forces 2

Physics not only contributes to our technological infrastructure but also forms the basis for future technological advances. It provides us the fundamental knowledge to understand and develop new techniques and technologies. Many professionals apply their knowledge of physics in their work. Mechanical, civil, aeronautical, electrical, chemical, and hydrological engineers all rely on the principles of physics. Medicine has also benefited: think of the X ray, MRI, CAT scan, color doppler tests, ECGs, resonance imaging, and radiation therapy, all advanced techniques that detect, manage, or cure ailments. Medical equipment, ranging from simple blood pressure monitors to complex heart-lung machines, pacemakers, and dialysis, were invented and improved through our understanding of physics. Physics also enhances our knowledge of other fields, such as agriculture, environmental science, and forensics. Let's take a look at how physics is related to other sciences.

Properties of Gases, Liquids, and Heat

The laws of mechanics apply all the way down to the atomic level. But if you want to know how 1023 molecules will behave in a small bottle, you don't need to analyze the motion of each molecule. Large numbers of molecules behave as a group in predictable ways and knowing how they behave is useful. Scientists such as Robert Boyle, Jacques Charles, Joseph Louis Gay-Lussac, John Dalton, and Amedeo Avogadro studied the behavior of gases and the relationships among pressure, volume, and temperature of a sample of gas. They developed various laws that could be applied to all gases. In the same way, scientists have studied the properties of liquids with respect to their volume, pressure, buoyancy, and flow. In physics, heat is studied as thermal energy. The study of how heat is related to pressure, density, and temperature is known as thermodynamics.

Waves, Light, and Sound

The laws of mechanics apply to waves on a spring, in water, or in air. All waves have some similar behaviors and properties. Knowing those properties can be very useful. Wave properties—amplitude, frequency, and wavelength, for example—have various applications in physics. We study these properties when we study light, sound, or periodic motion. Acoustics is the branch of physics devoted to sound and sound waves. Acoustics also includes ultrasound, infrasound, and vibrations. Acoustics applies to almost all aspects of our daily life, most obviously in the music and audio industries. Acoustics is also widely used in medical imaging. Optics is the branch of physics concerned with the behavior and properties of light. The laws of optics also have wide application, especially in the development of different types of lenses and mirrors, and of the fiber-optic networks that now connect the whole world. Because light is an electromagnetic wave, the laws of optics can also be applied to other forms of electromagnetic radiation, including X-rays, microwaves, and radio waves.

How Physics Links to Earth and Space Science

The tools and laws of physics are essential ingredients for an understanding of space and cosmology. Optical and radio telescopes, instruments that employ the properties of waves and optics, help scientists unravel the mysteries of the universe. The invention of space stations, satellites, rockets, and space shuttles took humans into space, further expanding our understanding of our world. These inventions were based on various laws of physics. The movement of heavenly bodies can be explained in terms of the physical phenomena of gravity, relativity, mechanics, thermodynamics, electromagnetic forces, and quantum mechanics. Closer to home, earth science also borrows heavily from the laws of physics. The structure and dynamics of Earth's interiors involve heat, pressure, and mechanics. Weather forecasters who work with atmosphere and weather systems must understand volume, pressure, velocity, density, heat, and electromagnetism. As you can see, physics not only helps us understand many other scientific disciplines, it also contributes to new technologies that improve the world we live in.

Quantum and Nuclear Forces

Two of the basic forces of the universe—the "strong" and the "weak" forces—are observed only on the atomic, or nuclear, scale. Though we can't directly see these forces in everyday life, we do experience their effects daily. For example, when we see the sun in the sky, we're seeing nuclear fusion at work. It is the sun's source of energy. Quantum mechanics is the branch of physics that studies the motions and interactions of submicroscopic bodies such as atoms, atomic nuclei, and elementary particles. Quantum laws provide formulas and designs for electronic devices, nuclear reactors, and superconductive magnets. Many modern inventions are based on quantum laws, including lasers, transistors, microchips, electron microscopes, and magnetic resonance imaging (MRI).