all the things in the world that you touch, feel, and taste every day, then you’ve come to the right place. The Handy Chemistry Answer Book uses a simple question-and-answer format to explain the chemistry in our daily lives. There are entire chapters on sustainable chemistry, the chemistry of cooking, and the chemistry of space. Some of these are questions we got from people like you! The questions in the chapter called “The World around Us” were all submitted from college students at the University of Michigan (our alma mater—Go Blue!) and Brandeis University.
We think that you’ve probably wondered, for just one more example, what sodium laureth sulfate is doing in your shampoo, but maybe never had a chance to ask. We are interested in explaining these things in plain language, and we’ve kept a conversational tone throughout the entire book, even with some very challenging subject matter. We hope that reading this book feels like you’re talking to someone about chemistry, even if you wouldn’t be caught dead doing that. There are chemical structures throughout this book, and we’ve used a simplified drawing system. Take what you can from these abstract drawings, but don’t dwell on them. Focus on the stories we’re trying to tell about molecules. And if you have a chemistry question you’d like to ask, or a chemistry story you’d like to share with us, please drop us an email. Finally, we both really enjoy working at our corporations and institutes of higher learning, respectively, and want to continue to do so for years to come. So every fact, implication, mistake, and opinion expressed herein is absolutely ours and ours alone,
and do not in any way represent the opinion or position of our employers, or any other person or organization.
Enjoy.
Ian Stewart Justin Lomont [email protected]
HISTORY OF CHEMISTRY
What is the earliest historical evidence of the study of chemistry?
Although they didn’t call it chemistry, people from ancient civilizations used chemical reactions in many aspects of their lives. Metalworking, including the extraction of pure metals from ores, and then combining metals to make alloys, like bronze, left many artifacts of early man’s chemistry experiments. Pottery, including the production and use of various glazes, fermentation to make beer and wine, and pigments and dyes for cloth and cosmetics are all evidence that man has always been fascinated by the ability to change matter.
Where was early chemistry developed?
While many civilizations learned how to make dyes and pigments, or ferment fruit into wine, the earliest theories about atoms and what makes up the chemical world came from ancient Greece and India. Leucippus in Greece and Kanada in India both came up with the idea that there must be a small, indivisible part of matter. The Greek word for “uncuttable” is atomos, clearly the root of the modern term atom. Kanada’s term for this similar concept was “paramanu” or simply “anu,” the indivisible element of matter.
What does the city of Miletus have to do with chemistry?
Miletus, one of the Greeks’ greatest cities, was located on the western coast of what is now Turkey and was home to where some of the earliest ideas about chemistry were recorded. During the sixth century B.C.E., the Milesian school of thought was founded, and the musings of three philosophers survived into the modern era: Thales, Anaximander, and Anaximenes. Thales thought the most basic building block of the universe was water and that the Earth floated on top of this celestial water. Anaximander challenged both of these ideas, proposing that the universe was born when fire and water (or hot and cold) separated from one another and that the Earth simply floated on nothing. Anaximenes, who was a friend or perhaps student of Anaximander, countered that air was the most basic substance and that air condensed to form water and evaporated to reverse that process.
Who first proposed the idea of elements?
Plato is often given this accolade as he was the first to use this term for his description of the five basic shapes that he believed made up the entire universe: tetrahedrons, icosahedrons, dodecahedrons, octahedrons, and cubes. He went on to ascribe each shape to a basic element, borrowing from Empedocles (see next question). The tetrahedron was fire; icosahedron, water; dodecahedron, aether; octahedron, air; cube, earth. While this association of basic geometrical shapes to the nature of the Universe obviously didn’t work out for him, Plato’s ideas did lead Euclid to invent geometry.
What did Empedocles believe were the four basic elements?
A Greek named Empedocles (who was not from Miletus, but rather Sicily) was the first to propose the four basic “elements.” These four elements were earth, air, water, and fire. These elements had a much different definition from that which chemists use today (which we’ll get to later). Unlike the modern definition of an element, Empedocles’ understanding of an element did not require it to be a pure substance. Water, for example, was obviously not the only liquid Empedocles had ever encountered. Earth represented solids, water represented liquids, air represented gases, and fire represented heat.
What fifth element did Aristotle add?
Although Empedocles is understood to have been the first to propose the four basic elements, Aristotle is sometimes given this credit. Aristotle did propose a fifth basic element though, which he called aether. Aether was a divine material that Aristotle said made up the stars and other planets in the sky.
The earliest theories of the atom came about in ancient Greece, where philosophers correctly surmised that there were different kinds of atoms and that they contained mostly empty space—all centuries before the invention of the microscope!
When did the theory of the atom come about?
The idea of the atom was originally proposed by ancient scholars. The philosophers Democritus and Leucippus are often credited with proposing the early notions of the atom, including the ideas that many different kinds of atoms exist, that there is a substantial amount of empty space between atoms, and that their properties are responsible for the properties of materials we see and interact with. For centuries, ideas about the structure and properties of the atom were based largely on conjecture and logical arguments, and it wasn’t until the 1800s that experiments began to allow atomic theory to advance to where it is today.
What is an element?
An element is the most basic form of a chemical substance. If you have an object made of a pure element, all of its atoms have the same number of protons (we’ll discuss what this is more a little later) and the same basic chemical properties. There are not many objects that we encounter on a daily basis that are actually composed of only a single element—most things are formed from atoms of several types of elements bonded together.
What separates ancient and modern chemistry?
While there’s not a clear, punctuating distinction between ancient and modern chemistry, there are a few major differences that separate the two. Modern chemists describe the world in terms of atoms, molecules, and electrons and have a relatively complete understanding of the basic particles that make up matter—at least insofar as is necessary to describe chemical transformations. Ancient chemists didn’t
