What Does Chemical Mean in Science?

Instructor: Laura Foist

Laura has a Masters of Science in Food Science and Human Nutrition and has taught college Science.

In this lesson we will learn what a chemical is, how it is defined in science, and the importance of chemicals to our life. We will also learn how society views chemicals versus the definition in science.

(Not so) Scary Chemicals

'Don't eat that burger, don't you know that fast food places fill their burgers with chemicals?!'

'That factory is pouring chemicals into the river.'

How often do you hear comments like this? Whether or not they are true, scientists will often hear these types of statements and laugh. That's because to a scientist everything can be considered a chemical.

When you plant a pepper, grow it, and pick it, it is still full of chemicals such as capsaicin and piperine. In fact, even you and I are made up of chemicals. It may not be the sort of chemicals that we typically think about when we hear 'chemicals', but in science these are all chemicals.

Defining Chemicals

The periodic table shows all of the elements found in the world
Periodic table

Everything in this world is made up of elements such as oxygen, iron, gold, and every other element you can find in the periodic table. A chemical is an element or any combination of these elements. For example, oxygen in the air is a chemical, and is always a combination of two oxygen elements. Elements are the building blocks of other chemicals, making a single element the simplest form of of a chemical.

Water, a combination of two hydrogen atoms bonded to an oxygen atom, is a chemical. The chemical name for water is dihydrogen monoxide. The chemical capsaicin in the peppers is what makes the pepper spicy.

Chemicals and the Human Body

First of all, the human body is made up completely of chemicals - from the air we breathe to the muscles that move our arms (chemicals including nitrogen, hydrogen, and oxygen). Yet not only is everything in our body chemicals, but in order for our body to function the chemicals are reacting with other chemicals in our body.

For example, when we eat a slice of bread (which is made up of chemicals), our body starts to break that bread down into chemicals that we can use. The starch (the main constituent in the bread) is broken down into glucose which gets absorbed and undergoes a process called glycolysis. Through this process the glucose is changed (through combining it with other chemicals and breaking it apart) into chemicals such as glyceraldehyde 3-phosphate and pyruvate. It is also turned into adenosine triphosphate (ATP) which in turn reacts with the chemicals in our muscles to give us the energy to move and work.

We need chemicals in order to live.

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