Introduction

This book, Energy Flow, is about Earth systems which involve changes and interactions between things. There is never change without energy.

 A waterfall on the island of Pohnpei, in Micronesia.  Photo by Alan Gould, Lawrence Hall of Science
 Waterfall in Hawai'i.  Photo by Alan Gould.

Energy may be a tricky concept to understand even though it is all around us, and inside of us. Gravitational energy holds our atmosphere on the surface of the Earth, and keeps our entire planet together. Energy from the Sun provides light and warmth to keep us from freezing. Energy from natural radioactivity deep inside the Earth causes earthquakes and volcanoes, and has shaped the surface of our planet over eons of time. Electrical energy illuminates our houses and runs our gadgets. We use energy in cooking. We know that food gives us energy which our bodies convert to muscle energy, body heat, mind energy, sexual energy, and nervous energy. We all need energy to survive. But energy is not easy to define. The energy in a gallon of gasoline, in a flashlight battery, or in a chocolate chip cookie is not something you can point to or easily communicate in a drawing.

Understanding how energy flows through Earth’s systems is absolutely essential if you are to understand the natural processes that shape our world, and the many ways that we—the human species—are changing it.

The more you realize what energy is, the more places you can “see” it in the world. Energy operates in the tiniest of systems, in the largest of systems and in every system in between. The energy in wind ranges from a gentle breeze delightfully caressing your hair to a hurricane force gale blowing down trees and ripping off the roofs of houses in a whole community. The energy of things moving downwards includes grains of sand falling in an hourglass, a skateboarder zooming down a steep mountain road, or a fearsome landslide with millions of tons of soil and rock. Astronomers use huge telescopes to try to detect tiny amounts of light reaching us from the most distant stars, yet light from the Sun can melt metal on the planet Mercury. Your compact disc player or CD-ROM in your computer uses the tiniest of lasers to read music or other information from plastic disks, while a larger laser system can cut through tissue in laser surgery or blast a hole in a piece of metal.

Energy can unfold very quickly or very slowly. The energy of tree roots growing in the ground is very slow, but powerful enough to crack sidewalks and damage houses over long periods of time. Movement of the ground along a fault line can warp a fence over many years or destroy a whole house in seconds.

In this book you will find several key concepts about energy and several intriguing examples of energy in Earth systems. Try to think of energy flow as happening in things around you in your everyday life, and the same forms of energy causing large scale catastrophic events.

This book, Energy Flow, is about Earth systems which involve changes and interactions between things. There is never change without energy.

Energy may be a tricky concept to understand even though it is all around us, and inside of us. Gravitational energy holds our atmosphere on the surface of the Earth, and keeps our entire planet together. Energy from the Sun provides light and warmth to keep us from freezing. Energy from natural radioactivity deep inside the Earth causes earthquakes and volcanoes, and has shaped the surface of our planet over eons of time. Electrical energy illuminates our houses and runs our gadgets. We use energy in cooking. We know that food gives us energy which our bodies convert to muscle energy, body heat, mind energy, sexual energy, and nervous energy. We all need energy to survive. But energy is not easy to define. The energy in a gallon of gasoline, in a flashlight battery, or in a chocolate chip cookie is not something you can point to or easily communicate in a drawing.

Understanding how energy flows through Earth’s systems is absolutely essential if you are to understand the natural processes that shape our world, and the many ways that we—the human species—are changing it.

 Niagara Falls.  Photo courtesy of U.S. Geological Survey
 Yosemite National Park.  Photo by Alan Gould

The more you realize what energy is, the more places you can “see” it in the world. Energy operates in the tiniest of systems, in the largest of systems and in every system in between. The energy in wind ranges from a gentle breeze delightfully caressing your hair to a hurricane force gale blowing down trees and ripping off the roofs of houses in a whole community. The energy of things moving downwards includes grains of sand falling in an hourglass, a skateboarder zooming down a steep mountain road, or a fearsome landslide with millions of tons of soil and rock. Astronomers use huge telescopes to try to detect tiny amounts of light reaching us from the most distant stars, yet light from the Sun can melt metal on the planet Mercury. Your compact disc player or CD-ROM in your computer uses the tiniest of lasers to read music or other information from plastic disks, while a larger laser system can cut through tissue in laser surgery or blast a hole in a piece of metal.

Energy can unfold very quickly or very slowly. The energy of tree roots growing in the ground is very slow, but powerful enough to crack sidewalks and damage houses over long periods of time. Movement of the ground along a fault line can warp a fence over many years or destroy a whole house in seconds.

In this book you will find several key concepts about energy and several intriguing examples of energy in Earth systems. Try to think of energy flow as happening in things around you in your everyday life, and the same forms of energy causing large scale catastrophic events.


 For new material relating to this chapter, please see the GSS website “Staying Up To Date” page:
http://www.globalsystemsscience.org/uptodate/ef/ch0


Comments