相关实验视频

能源和美国经济:一个生物物理的视角

C J Cleveland, R Costanza, C A Hall

    Science (New York, N.Y.)
    |August 31, 1984
    PubMed
    概括

    国家能源使用与经济活动密切相关,影响国内生产总值和生产率. 能源投资回报率下降表明,未来的经济增长取决于新能源的净能源产量.

    相关概念视频

    Energy00:58

    Energy

    The universe is composed of matter in different forms, and all forms of matter contain energy.  The different forms of energy on Earth originate from the Sun—the ultimate energy source. For instance, plants capture light energy from the Sun, and through the process of photosynthesis, convert it into chemical energy. This stored energy from plants can be harnessed in many ways. For example, eating plant products as food provides energy for our body to function, and burning wood or coal...
    Energy Basics02:27

    Energy Basics

    Chemical reactions, such as those that occur when you light a match, involve changes in energy as well as matter.
    What is Energy?04:10

    What is Energy?

    The universe is composed of matter in different forms, and all forms of matter contain energy.  The different forms of energy on Earth originate from the Sun — the ultimate energy source. Plants capture light energy from the Sun, and, via the process of photosynthesis, convert it into chemical energy. This stored energy from plants can be harnessed in many ways. For example, eating plant products as food provides energy for our body to function, and burning wood or coal (fossilized plants)...
    Power and Energy01:12

    Power and Energy

    The power and energy delivered to an element are subjects of great significance in the field of electrical engineering. It is a well-known fact that a 100-watt light bulb emits more light than a 60-watt one. Therefore, power and energy calculations play a crucial role in the analysis of electrical circuits.
    Power, defined as the time rate of expending or absorbing energy, is quantified in units called watts (W). The relation between power and energy is mathematically given as
    Energy Diagrams - I01:14

    Energy Diagrams - I

    The dynamics of a mechanical system can be easily understood by interpreting a potential energy diagram. Since energy is a scalar quantity, the interpretation of the dynamics of the system becomes even simpler.
    Take the example of a skater on a parabolic ramp. The potential energy at different points along the ramp will be proportional to the height of the ramp, which varies quadratically with the horizontal position on the ramp. As the skater moves down the ramp from the highest position,...
    The First Law of Thermodynamics01:13

    The First Law of Thermodynamics

    The first law of thermodynamics deals with the total amount of energy in the universe. It states that this total amount of energy is constant. In other words, there has always been, and always will be, exactly the same amount of energy in the universe. Energy exists in many different forms. According to the first law of thermodynamics, energy may transfer from place to place or transform into different forms, but it cannot be created or destroyed. The transfers and transformations of energy...