Physics
Energy and the Environment
Energy and the environment are interconnected in the study of physics. The use and generation of energy have significant impacts on the environment, including air and water pollution, habitat destruction, and climate change. Understanding these interactions is crucial for developing sustainable energy sources and minimizing environmental harm.
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6 Key excerpts on "Energy and the Environment"
- I. Johnsen, S.E. Jorgensen(Authors)
- 1989(Publication Date)
- Elsevier Science(Publisher)
CHAPTER 3 PRINCIPLES OF ENERGY BEHAVIOUR APPLIED TO ENVIRONMENTAL ISSUES 3.1. FUNDAMENTAL CONCEPTS RELATED TO ENERGY. Energy is defined as the ability to do work, and the behaviour of energy can be described by the first and second laws of thermodynamics. P.3.1. The first law of thermodynamics states that energy may be transformed from one type to another but is never created or destroyed. It can also be applied in a more ecological way as follows: you can not get something for nothing - there is no such thing as a free lunch (Commoner, 1971). Thus when a change of any kind occurs in a closed system (see 2.3 for definition) an increase or decrease in the internal energy occurs, heat is evolved or absorbed and work is done. Therefore: A E = Q + W (3.1 1 where AE = change in internal energy Q = heat absorbed W c work done on the system As mentioned in 2.1 a relationship exists between mass and energy, which dictates that energy is produced as a result of nuclear processes. Equation (3.1) assumes that such processes have not taken place. In environmental science we are primarily concerned with the quantity of incident solar energy per unit area in an ecosystem and the efficiency with which this energy is converted by organisms into other forms. This situation is illustrated in Fig. 3.1, where the fate of solar radiation upon grass-herb vegetation of an old field community in Michigan is shown (Golley, 1960). The transformation of solar energy to chemical energy by plants conforms with the first law of thermodynamics: - 143- Solar energy chemical energy heat energy assimilated by plants - of plant tissue + of respiration (3.2) For the next level in the foodchain, the herbivorous animals, the energy balance can also be set up: Sunlight 1.97 * l o 9 Respiration Gross Product ion Net Production - - O.L .107 2 . ~ . 107 2.0.10~ Fig. 3.1. vegetation of an old field community in Michigan.
eBook - PDFWeather and Life
An Introduction to Biometeorology
- William P. Lowry(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
To accomplish his task, he needs an adequate description of the physical environment of each organism and of the variability of the environment. He needs an understanding of the processes determining the range of environments in which the life of each species can be maintained. The agronomist and the forester have the same need as the ecologist to know the mechanisms by which plants respond to the physical environment, though their objective is not so much to explain limits as to optimize plant response as expressed in some special measure of performance. Similarly, the animal husbandman wants to optimize response of a different set of biological processes to the same set of physical processes. Though the problems of the entomologist, the plant pathologist, or the environmental health physician may seem entirely different, all are concerned with the response of organisms to the physical environment. Energy and Environment Energy is the word we use in referring to that property of matter which may be transferred from one place to another, may appear in the form of motion or the potential for motion, and may appear in a form related to heat. From beginning physics, recall that positional energy is called potential energy, and the energy of gross motion is called kinetic energy. The internal energy of composition is chemical energy, and the internal energy of motion is heat. Within the purely physical environment, energy exists in these different forms. It is converted and transferred by different pro-cesses. In the hydrosphere and in the lithosphère, the relative Energy and Ecology 11 importance of these processes may be different from that in the atmosphere, but the processes are the same and are governed by the same physical principles.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- White Word Publications(Publisher)
In particle physics, this inequality permits a qualitative understanding of virtual particles which carry momentum, exchange by which and with real particles, is responsible for the creation of all known fundamental forces (more accurately known as fundamental interactions). Virtual photons (which are simply lowest quantum mechanical energy state of photons) are also responsible for electrostatic interaction between electric charges (which results in Coulomb law), for spontaneous radiative decay of exited atomic and nuclear states, for the Casimir force, for van der Waals bond forces and some other observable phenomena. Applications of the concept of energy Energy is subject to a strict global conservation law; that is, whenever one measures (or calculates) the total energy of a system of particles whose interactions do not depend explicitly on time, it is found that the total energy of the system always remains constant. • The total energy of a system can be subdivided and classified in various ways. For example, it is sometimes convenient to distinguish potential energy (which is a function of coordinates only) from kinetic energy (which is a function of coordinate time derivatives only). It may also be convenient to distinguish gravitational energy, electric energy, thermal energy, and other forms. These classifications overlap; for instance, thermal energy usually consists partly of kinetic and partly of potential energy. • The transfer of energy can take various forms; familiar examples include work, heat flow, and advection, as discussed below. ________________________ WORLD TECHNOLOGIES ________________________ • The word energy is also used outside of physics in many ways, which can lead to ambiguity and inconsistency. The vernacular terminology is not consistent with technical terminology.
- Axel Kleidon(Author)
- 2016(Publication Date)
- Cambridge University Press(Publisher)
2 Energy and entropy 2.1 The central roles of energy and entropy Different forms of energy and conversions among these are central to the dynamics of the Earth system and to the application of thermodynamics. Energy is defined as a property of matter and radiation that is linked to the capacity to perform work. Performing work relates to the conversion of one form of energy to another. The actual capacity to perform work is described by free energy, which is linked to the dispersal of energy across the microscopic scale of atoms and molecules and is described by its entropy. This chapter focuses on the description of different forms of energy and entropy relevant to the Earth system; but we should keep in mind that the dynamics of the Earth system are not shaped by the magnitudes of energy or entropy in the system, but rather by the conversion rates that are related to differences in energy and entropy. These conversion rates are subject to the laws of thermodynamics and are dealt with in the following chapters. Earth system processes involve different forms of energy. Solar and terrestrial radiation involve radiative energy. Atmospheric motion is associated with kinetic energy, while cloud droplets are associated with gravitational, or simply potential, energy. Soil moisture on land is linked to the energy associated with the binding energy of water to the soil matrix and with potential energy. The concentration of constituents in air, water, and solids as well as biomass is linked to forms of chem- ical energy. Likewise, any other process within the Earth system is associated with some form of energy. In this chapter, the major forms of energy are described and broad estimates of their magnitude are given to illustrate how these are quantified. A more hidden aspect in these forms of energy is its spread at the scale of atoms and molecules that is described by entropy. At the microscopic scale, energy is stored in discrete, countable units.
eBook - PDF- Belal E. Baaquie, Frederick H. Willeboordse(Authors)
- 2009(Publication Date)
- CRC Press(Publisher)
64 Exploring Integrated Science A powerful idea in physics is that of invariants , that is, things that do not change as a system evolves in time (see also Chapter 2). The existence of invariants and their use allows us to place constraints on the possible dynamics of a system even though we might be ignorant of the details. Denoting total energy by E we have the fundamental (classical) relation Total energy of system D Kinetic Energy C Potential Energy ) E D T C U: (3.40) Suppose the system has energy E 1 at time t 1 and energy E 2 at a later time t 2 , then, the change in energy is E D E 2 NUL E 1 . Conservation of energy implies that E D 0 (3.41) ) T C U D 0: (3.42) Note an important fact that since all we know is that E D 0 , the absolute value of E has not been fixed. Hence, energy is only defined up to a constant, since E and E C constant would both be equally conserved. 3.8 Free energy Energy is everywhere! Einstein’s famous formula E D mc 2 tells us that even the mass of a body is a form of congealed energy (see Chapter 22). All material things are different forms of energy. If energy is indeed everywhere, why is there always a fear that our society is “running out energy”, or that there is a shortage of fuel? Why are we asked to reduce, reuse and recycle? We all intuitively know that energy is precious and that possessing energy is of high value. So we need to wonder: Is all energy equal? Or is there a certain energy that is more desirable than another? Fig. 3.20: Coal provides us with “useful” energy. One of the main developments of science in the nineteenth century was the realization by Sadi Carnot, Rudolf Clausius and others that useful energy — energy that can do mechanical work, energy that can be “controlled” and directed — is a very special kind of energy. This special form of energy is called “free energy” to differentiate it from energy in general. Let us consider the forms of energy that we find useful.
Available until 26 Apr |Learn more- Greg de Nevers, Deborah Stanger Edelman, Adina Merenlender(Authors)
- 2013(Publication Date)
- University of California Press(Publisher)
179 Energy is a fundamental unifying concept for physical and biologi-cal scientists because it drives all Earth systems. Energy is neither cre-ated nor destroyed, it simply changes form. Therefore, energy can never be “used up.” When nuclear fusion in the dense gas cloud of the sun releases the energy of the atom, it transforms that energy to various forms of electromagnetic energy. The exact amount of energy that was held in the nuclear bonds of the hydrogen or helium atoms reacting in the sun is the amount released as light, heat, and other forms of energy. FORMS AND SOURCES OF ENERGY Forms of Energy Energy exists in a variety of forms. We know and are familiar with electromagnetic energy as light, heat, radio waves, television signals, and microwaves. Importantly, energy can be converted from one form to another. Nuclear energy of atoms of the sun is converted to electro-magnetic energy, which is captured by plants and stored as chemical energy. Chemical energy stored in food is used to power the mechanical movements of activity—to walk, open doors, hunt. Mechanical energy is used to move cars, open bottles, and crack nuts with a nutcracker. Mechanical energy is the force that dug the Grand Canyon and that powers turbines to create electricity at hydroelectric dams. Thermal 7 Energy and Global Environmental Issues 180 | Energy and Global Environmental Issues energy is what we commonly experience as heat. Electrical energy is converted to thermal energy in toasters and ovens to prepare the chem-ical energy in food. The chemical energy derived from the food is con-verted to the mechanical energy of pushing down the toaster button. Energy is commonly converted from one form to another throughout our lives every day. Thinking about these transformations or conver-sions helps elucidate the energetic basis of life on Earth.
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