Atoms and small molecules are incredibly tiny pieces of physical matter. For example, a single carbon atom is roughly 0.15 nanometers across. This makes the nanometer the perfect unit for describing chemical bonds and molecular structures.
Students often struggle to picture just how small a nanometer really is. Imagine a normal human hair sliced into one hundred thousand equal slivers. Just one of those tiny slivers would be about one nanometer thick.
A standard sheet of paper is about one hundred thousand nanometers thick. To put it in perspective, your fingernails grow about one nanometer every second. Beyond measuring physical objects, the nanometer also measures the invisible waves of light.
Light travels through space in waves that have distinct peaks and valleys. The physical distance between two side-by-side peaks is called the wavelength. In analytical chemistry, we identify unknown substances by the specific wavelengths of light they absorb or give off.
Our human eyes perceive these different wavelengths of light as different vivid colors. The visible light spectrum spans from about 400 to 700 nanometers. Violet light has shorter waves that typically measure near 400 nanometers.
Red light has longer waves that measure closer to 700 nanometers. Measuring these tiny distances helps chemists understand the basic behavior of both matter and energy.