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2. Changes in Energy

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About this Lecture


In this mini-lecture, we discuss changes in energy. As we move through this mini-lecture, we consider: (i) the exchange between kinetic and potential energy in a pendulum system, including the system’s efficiency; (ii) energy conversion to heat by looking at examples of a satellite re-entering Earth’s atmosphere and the supersonic aircraft, Concorde; (iii) electrical energy conversion into heat from boiling a kettle; (iv) where electricity comes from and how much energy we use; (v) energy in sound; (vi) closed systems and an example of an imperfect closed system (a vacuum flask); (vii) the usefulness of energy to do work; (viii) when thermal energy is useful to do work; and (ix) friction.


In this course, Professor Douglas Halliday (Durham University) explores energy. In the first mini-lecture, we discuss the big picture of energy, looking at types of energy, key principles, and units. In the second mini-lecture, we consider changes in energy by looking at examples of various energy exchanges involving kinetic and potential energy, heat, electrical energy, etc. The third mini-lecture introduces the concept of the conservation of energy and works through four related examples. In the fourth mini-lecture, we discuss the concept of work in greater detail and go through a couple of examples. In the fifth mini-lecture, we introduce the concepts of power and efficiency, working through some examples and looking at how to improve the efficiency of a system.


Douglas Halliday is a Professor of Physics at Durham University and a Director at the Durham Energy Institute. His research involves next-generation thin-film photovoltaic (solar) devices. Professor Halliday is also the Director of the Centres for Doctoral Training in Energy and Global Challenges Research as well as the Chair of the European Universities Association Energy and Environment Platform (EUA-EPUE).

Cite this Lecture

APA style

Halliday, D. (2022, January 14). Energy - Changes in Energy [Video]. MASSOLIT.

MLA style

Halliday, Douglas. "Energy – Changes in Energy." MASSOLIT, uploaded by MASSOLIT, 14 Jan 2022,

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