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  • Explain the difference between a principle and a law.
  • Explain the difference between a model and a theory.

Two Canada geese flying close to each other in the sky.
The flight formations of migratory birds such as Canada geese are governed by the laws of physics. (credit: David Merrett)

The physical universe is enormously complex in its detail. Every day, each of us observes a great variety of objects and phenomena. Over the centuries, the curiosity of the human race has led us collectively to explore and catalog a tremendous wealth of information. From the flight of birds to the colors of flowers, from lightning to gravity, from quarks to clusters of galaxies, from the flow of time to the mystery of the creation of the universe, we have asked questions and assembled huge arrays of facts. In the face of all these details, we have discovered that a surprisingly small and unified set of physical laws can explain what we observe. As humans, we make generalizations and seek order. We have found that nature is remarkably cooperative—it exhibits the underlying order and simplicity we so value.

It is the underlying order of nature that makes science in general, and physics in particular, so enjoyable to study. For example, what do a bag of chips and a car battery have in common? Both contain energy that can be converted to other forms. The law of conservation of energy (which says that energy can change form but is never lost) ties together such topics as food calories, batteries, heat, light, and watch springs. Understanding this law makes it easier to learn about the various forms energy takes and how they relate to one another. Apparently unrelated topics are connected through broadly applicable physical laws, permitting an understanding beyond just the memorization of lists of facts.

The unifying aspect of physical laws and the basic simplicity of nature form the underlying themes of this text. In learning to apply these laws, you will, of course, study the most important topics in physics. More importantly, you will gain analytical abilities that will enable you to apply these laws far beyond the scope of what can be included in a single book. These analytical skills will help you to excel academically, and they will also help you to think critically in any professional career you choose to pursue. This module discusses the realm of physics (to define what physics is), some applications of physics (to illustrate its relevance to other disciplines), and more precisely what constitutes a physical law (to illuminate the importance of experimentation to theory).

Science and the realm of physics

Science consists of the theories and laws that are the general truths of nature as well as the body of knowledge they encompass. Scientists are continually trying to expand this body of knowledge and to perfect the expression of the laws that describe it. Physics is concerned with describing the interactions of energy, matter, space, and time, and it is especially interested in what fundamental mechanisms underlie every phenomenon. The concern for describing the basic phenomena in nature essentially defines the realm of physics .

Questions & Answers

Will the current used on the load side affect the current on the supply side.
Shevanan Reply
wave is a disturbance that travels through a medium and transfer energy from one place to another without causing any permanent displacement of the medium itself
Bello Reply
what is wave
atiba Reply
wave is a disturbance that travels through a medium and transfer energy from one place to another without causing any permanent displacement of the medium itself
Bello
measurements of the period of a simple pendulum in an experiment are 20 oscillations for a give length of the pendulum 30.50secs
Praise Reply
patient with a pacemaker is mistakenly being scanned for an MRI image. A 10.0-cm-long section of pacemaker wire moves at a speed of 10.0 cm/s perpendicular to the MRI unit’s magnetic field and a 20.0-mV Hall voltage is induced. What is the magnetic field strength
Muhammad Reply
fundamental and derived quantities
Kadijatu Reply
is any thing that has weight or mass and can occupy space
Kadijatu
explain why the earth is an exact shere
Akinyemi Reply
because the pull of gravity is equal on all sides
Paul
how long did sun take to rich the earth
Billy
A tennis ball is projected vertically up with a velocity of 100m/s the top of a tower 50m high. Determine the a). height reach from the ground. b). Time to reach the hmax.
Luca Reply
100×50=5000
Muhammad
what are the formula and calculation
Brianca Reply
what are the formula for resistance, ohm's law, and electric current
Brianca
I=V/R and so R=V/I
Akiiza
what is gamma rays
Uche Reply
gamma ray is an energetic ray .it does not have acharge
Merkew
what is wave
Faruq Reply
What happens to the mass of water in a pot when it cools, assuming no molecules escape or are added? Is this observable in practice? Explain.
Angel Reply
please explain to me,coz I have no idea
Brianca
what is a magnetic field
Jedaiah Reply
magnetic field is the area around a magnet where the magnetic force is exerted or felt.
Paul
what is the first Faraday's law
Abba
Formula for Newton 1st law
Maryam Reply
what is physics
Isa Reply
Physics is a way to see and solve things around us
Prajukta
Practice Key Terms 9

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Source:  OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
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