Student Article
The Science of Smell: How Our Nose Understands Odors
Molecule (noun): The smallest unit of a chemical compound that retains its properties.
Receptor (noun): A protein on a cell that receives chemical signals.
Olfactory (adjective): Related to the sense of smell.
Context (noun): The circumstances that help explain something.
Anosmia (noun): The total loss of the ability to perceive smell.
What’s that smell? The science behind your nose.
How your nose knows what you’re smelling
When you inhale the scent of roses or fresh-baked bread, your body performs a complex task. Smell begins with odor molecules — tiny particles that float through the air. These molecules enter your nose and bind to specialized smell receptors located on sensory nerve cells high up in your nasal cavity. These receptors then send signals to your brain’s olfactory bulb, located just behind your nose.
Your brain uses patterns to recognize scents
Humans have around 400 types of smell receptors. One odor molecule can bind to many different receptors, creating a unique pattern of neural activity. Your brain interprets that pattern as a specific smell.
Why we love some smells and hate others
So why does fresh popcorn smell great, but rotten eggs make us gag? Smell plays a protective role — stench often signals danger, such as rotting food. However, preferences aren’t universal. Dr. Andreas Keller from Rockefeller University explains that our response to smells is shaped by both genetic differences and life experience. For instance, butyric acid smells like Parmesan to some, vomit to others. The surrounding context can shape how we interpret that scent.
Some people can’t smell certain things
Our sense of smell isn’t perfect. Most people have at least one “blind spot” — an inability to detect certain molecules. One famous example is the distinct smell in urine after eating asparagus, which some people can’t detect at all. Complete smell loss, or anosmia, can occur due to a cold, head injury, or sinus infection. This loss impacts more than just food flavor; many people describe the experience as emotionally isolating, as if cut off from the world. Fortunately, smell may return over time or be helped by “smell training,” where people repeatedly sniff strong scents like rose or clove oil to re-engage the olfactory system.
© Anand Jagatia / Our Media
Molecule (noun): The smallest unit of a chemical compound that retains its properties.
Receptor (noun): A protein on a cell that receives chemical signals.
Olfactory (adjective): Related to the sense of smell.
Context (noun): The circumstances that help explain something.
Anosmia (noun): The total loss of the ability to perceive smell.