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Part 5 – The Five Senses – The Sense of Smell


Have you ever wondered what you smell when you “smell the roses” in the springtime?  What makes a smell is something that is too small to see with your eyeball alone.  It is even too small to be seen with a microscope!  What you smell are tiny things called odor particles.  Millions of them are floating around waiting to be sniffed by your nose

You smell these odors through your nose, which is almost, like a huge cave built to smell, moisten, and filter the air you breathe.  As you breathe in, the air enters through your nostrils, which contain tiny little hairs that filter all kinds of things trying to enter your nose, even bugs!  These little hairs are called cilia and you can pretend that they sweep all the dirt out of the nasal cavity, which is the big place the air passes through on it’s way to the lungs.  After passing through the nasal cavity, the air passes through a thick layer of mucous to the olfactory bulb.  There the smells are recognized because each smell molecule fits into a nerve cell like a lock and key.  Then the cells send signals along your olfactory nerve to the brain.  At the brain, they are interpreted as those sweet smelling flowers or that moldy cheese.

Our sense of smell is connected really well to our memory.  For instance, the smell of popcorn can remind you of being at the movies with a friend or the smell of tar can remind you of the house being re-roofed.   Humans have seven primary odors that help them determine objects. Listed below are the seven odors.

     Odor                                       Example

    Camphoric                             Mothballs

    Musky                                     Perfume/Aftershave

    Roses                                       Floral

    Pepperminty                         Mint Gum

    Ethereal                                   Dry Cleaning Fluid

    Pungent                                   Vinegar

    Putrid                                       Rotten Eggs


 ð If your nose is at its best, you can tell the difference between 4000-10,000 smells!

 ð As you get older, your sense of smell gets worse. Children are more likely to have better senses of smell than their parents or grandparents.

 ð People who cannot smell have a condition called Anosmia.

 ð Humans use insect warning chemicals, called pheromones, to keep away pesky insects!

 ð Dogs have 1 million smell cells per nostril and their smell cells are 100 times larger than   humans!

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