Scientific Pathways

Evolution is the process through which living things change with time, adapting to the changing environment around them, and new species form. Fossils provide important evidence for the theory of evolution, but so too do other kinds of evidence, such as the distribution of modern species, animals' appearance, and DNA. This book offers a comprehensive and lavishly illustrated account of Darwin's observations and theory of evolution, the body of knowledge that has been added to by successive generations of scientists, the latest information on what we know, recent discoveries, and likely future breakthroughs in understanding. Supplemental content includes an activity spread, a substantial and highly detailed timeline, and a list of key people with mini-biographies.

Light fills our world with color and life. Without light, the world we are used to would not exist at all. Light aids in plant growth, plants then provide the food for animals to eat, thus beginning the food chain on Earth. In this way, light makes possible almost all of the life on our planet. Light is also increasingly important to people for other reasons. Modern telecommunications, including telephones and the Internet, rely on beams of laser light that shine through tiny fiber-optic cables. Light makes possible all manner of cutting-edge technology, from telemedicine to virtual reality, and from special effects to CD players. Scientists have spent great amounts of time over the centuries trying to understand light. Although early civilizations knew what light was and how to use it, the ancient Greeks and Romans were the first to try to find out how and why light worked as it did. Later scientists believed that light was a stream of particles; others thought it must be a train of waves. Eventually scientists realized that light is a form of radiation similar to radio waves and X-rays, and that it can be a wave and a particle at the same time. These discoveries led to the theory of quantum mechanics, which seeks to explain the world inside the atom. Meanwhile, attempts to measure the speed of light produced the world of relativity, where space and time behave in unexpected ways. The story of light is a tale of how some very different scientific theories gradually build on one another to give us a better understanding of the world. Eventually, through the work of many different scientists and over a long period of time, one theory stands out among all the others as the best explanation. In the case of light that process has taken more than 2,000 years. This book retells this epic trials and errors in vivid detail and with lavish photographs and illustrations. Supplemental content includes an activity spread, a substantial and highly detailed timeline, and a list of key people with mini-biographies.

In the 1800s, an Australian monk named Gregor Mendel was experimenting on pea plants as he tried to learn how a single cell could grow into an entire human. Today we can see the results of his work in almost every aspect of modern medicine. This book explores genetics through its long and controversial history to how its discoveries have shaped modern society.

Gravity is everywhere. It is the force that keeps the earth orbiting around the sun. Yet, it has always been one of the most mysterious forces throughout human history. This book explores some of the scientists responsible for what we know about gravity and how this knowledge has impacted modern society.

Greek philosophers first hypothesized that matter was composed of atoms, but the theory would not resurface again until the late 17th century. The idea that that atoms joined to form structures called molecules first appeared in the 19th century and helped explain why gases, liquids, and solids behave differently from one another. In the 20th century subatomic particles were discovered-electrons, protons, and neutrons-and atomic structure was finally understood. These breakthroughs led to the development of quantum theory and quantum mechanics. This book details the inspiring and heroic discovery, delving deeply into intriguing stories, reviewing major scientific landmarks, and introducing readers to the vivid men and women who helped discover and map the microscopic universe that is the atom. Supplemental content includes an activity spread, a substantial and highly detailed timeline, and a list of key people with mini-biographies.

People throughout time have attempted to make sense of the earth, why there are earthquakes, how rocks are formed, and more. Earth, before people came to be and since, has a rich history. This book takes a look at some of the early scientific and cultural beliefs about the Earth and how discoveries have shaped our modern culture.

The quest to understand how electricity works has led to some of the most important discoveries and inventions of all time. Scientists have figured out how to harness the power of electricity on a very large scale in massive power plants and on a very tiny scale in computer circuits. This book includes geniuses, like Benjamin Franklin, Nikola Tesla, and Thomas Edison. Our modern ideas have been assembled over a long period as scientists built upon the work of their predecessors. This book reveals what we have learned in the past, what we have discovered in the present, and what remains to be explored in the future. Supplemental content includes an activity spread, a substantial and highly detailed timeline, and a list of key people with mini-biographies.

Ten thousand years ago, life was different. People were nomadic, and their life spans were short. During this time, people practiced trepanning, one of the early human medical procedures. Today, the diseases that wiped out millions just a few hundred years ago have been completely eradicated thanks to developments in medicine. Readers explore some of the earliest medical discoveries, how medicine has developed, and how it continues to have an impact on modern society.