A Change For the Better
One of the fascinating things about chemistry is the way in which the chemical elements drastically change their behaviour when they combine to make new substances.
Ordinary table salt, or sodium chloride, can be made from the green gas, chlorine, and the silvery metal, sodium. Because sodium and chlorine are so reactive, we don’t find them in their free uncombined state in nature. However, we can extract them from substances like salt.
Furthermore, because of their reactivity, they can be highly dangerous. A piece of sodium the size of a pea can ignite if it comes into contact with water. Chlorine was one of the poisonous gases used in World War 1. Chlorine and sodium are quite hazardous on their own but become benign when combined into table salt. They completely change their form and properties in this substance.
The explanation for this dramatic change in sodium and chlorine stems largely from the profound difference one little electron makes. When sodium chloride forms, every atom of sodium that reacts with chlorine gives an electron to a chlorine atom. This electron exchange changes the neutral atoms into oppositely charged ions, which attract each other so strongly they form stable salt. It’s certainly a change for the better.
So next time you sprinkle salt on your fish and chips, be thankful for the difference that moving one electron can make.
The diversity and complexity we see in the world around us can be reduced to a hundred or so building blocks. People, skyscrapers, algae all draw on the same set of chemicals. What makes us different at that level is the type, number and combinations of those physical elements.
Centuries ago, humans were thought to be of a different order because our basic ingredients came from a sphere of elements not available to other living beings or inanimate things. Now we know that we share the same chemical resources. As a result, we must ask different questions about our identity. In what ways are we different from other species? Are we different indeed? Does this difference matter? If so, what are the privileges and responsibilities we carry in this position?
These are tougher questions than people faced in the past. They had a more clear-cut sense of the role and place of humanity in the greater scheme of things. Our knowledge must be integrated into our way of understanding these matters. We will have to ask questions that they never thought of asking.
It helps, too, to keep in mind that we are only considering this matter on a purely physical level. Just as a stop light can be explained at the level of atoms and electrons, electricity and colours, signals and communication, so we need to think about higher levels of explanation of our humanity. Chemistry is one level, meaning and purpose another.
We live in an era which looks for explanations at the atomic level as well as at the level of the cosmos. We look for ways to make grand theories out of the vast amount of detailed information available in this technological age. We can do work at the level of physics and chemistry, asking questions about the nature of quirks and black holes. We examine sociological trends, economic status, psychological qualities and the like. We know more about ourselves and about the universe than any other previous generation.
Yet we still struggle with the big questions about what it means to be human. Perhaps this is even a greater challenge for us now. Where do we look for answers to the questions of meaning and purpose? Religion? Ethics? Philosophy? Politics and economics? How would you finish the sentence “The good life consists in...”? Why is this worthwhile?
Dr. David Humphreys and Debbie Hughes
© August 2004
