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The Sound of Science - 'What makes smell smelly?'


The Sound of Science - 'What makes smell smelly?'

Welcome to The Sound of Science from WNIJ and NIU STEAM. It’s a weekly series explaining important STEM concepts. Today’s hosts are Jeremy Benson and Newt Likier.

We have a question here from one of our campers, who asks what makes smells smelly? I bet Jeremy knows.

Well, there are two main components: the molecules in the air and the receptors in our nose. Let’s start with the molecules because without them, there’s nothing for our nose to sniff. Every smell is a bunch of what we call odorants, and those odorants can come from pretty much anything in the world. They’re usually released when an object is undergoing some sort of change or chemical reaction.

Like when you can smell a neighbor’s fire pit burning or some cookies baking in the oven. In both these cases, it’s heat that causes the change that releases the odorants, but there are a bunch of other ways to make the world smellier too.

Once those molecules are in the air, they disperse. Wherever there’s a high density of particles, they want to spread out as far as possible. You might have seen this in action when you put a bit of salt or sugar in water. Odorants start jammed together in one location and then disperse outward. If you smell something, an odorant has found your nose!

Inside your nose are a bunch of very sensitive receptors called olfactory sensory neurons. Olfactory is the fancy way of saying related to smells, and the neuron part just means the cell sends and receives synapses with the brain.

All the information from those neurons goes to the olfactory bulb, the olfactory bulb is a pretty important part of our sensory system. It can distinguish between scents, help us block out the smells we don’t need to pay attention to, and communicate with our other brain structures. After receiving input from the neurons, the bulb does some preliminary processing and then sends its findings off to other parts of the brain.

Smell has been linked to memory, emotion, and learning. Whenever I smell chlorine, I remember swimming in the pool when I was a kid.

And whenever I smell rubbing alcohol, I remember getting shots at the doctor’s office.

If there’s anything you want to learn about the world, send us an email at niusteam@niu.edu.

This has been the Sound of Science on WNIJ. Where you learn something new every day.

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