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A Beginner’s Guide

By Vaclav Smil
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Energy by Vaclav Smil

Energy (2006) offers insights into one of the most elusive concepts in the spectrum of human thought: energy. By understanding what energy is, how it has helped us get where we are today, and what dangers our reliance on certain forms of energy poses, we will be better equipped to handle the challenges faced by modern civilization.

Key idea 1 of 8

The concept of energy has developed over centuries.

Looking at the way we use the word “energy,” it’s clear that most of us aren’t entirely sure what energy actually is. For example, we say that charismatic speakers “energize the crowd,” or that we feel more energetic after rigorous training for our upcoming half-marathon.

Yet, these are figurative at best. In fact, it’s impossible for us to have more energy after spending hours exerting ourselves. So if it’s not science or physics, what informs our conception of energy?

In essence, when we talk about “energy,” we’re using a broad term that encompasses various types of energies. The term stems from the Greek word energeia, coined by Aristotle, which signifies motion, action or work. Today, energy is usually thought of as the capacity to do work, i.e., our ability to affect change.

This kind of work could be as simple as sitting in a room and contemplating the cosmos. Though you may seem inert, your body is indeed working – your heart pumps blood, your stomach digests food, etc. And that takes energy.

The first law of thermodynamics, which states that energy can neither be created nor destroyed, demonstrates that “energy” is often just an abstract concept that describes the conversion of more varied energies.

To illustrate this, try rubbing your hands together very quickly. You’ll notice that they get warm. This isn’t because your hands have become “energized.” Rather, as you rub your hands together, kinetic energy (movement) is converted to thermal energy (heat), thus causing them to feel warm.

Mankind – including scientists such as Joules, Watt and Einstein – has been poring over the essence of energy for centuries. Over the years, scientists have created systems to measure these seemingly mystical energies – such as the International System of Units – and have used them to gain a better understanding of how our world works.

Energy is indeed a complex concept. Over the course of these blinks, we’ll unravel the mystery and show you the role that energy plays for all living things on our planet.

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