Olfaction
Olfaction is your sense of smell, which also shapes how you taste food.
A pot of soup on the stove sends tiny bits of itself up into the air. Those bits float across the room and land inside your nose. Cells in your nose pick them up and send a signal to your brain as a smell. That smell also shapes how the soup tastes, which is why food seems flat when your nose is blocked.
Explaining olfaction by grade level
Hold your nose and try to taste a piece of candy. It is hard to tell the flavor. Your nose and tongue work as a team. When you block your nose, your brain gets less flavor from the candy.
Projects that explore olfaction
Your sense of smell shapes how you taste food. About 80 to 90 percent of what you sense as taste comes from smell. Block the nose and flavor nearly vanishes. You can test this by timing how long it takes to name a candy flavor with the nose held shut versus open.
Your nose can recognize thousands of scents. But some smells are much harder to tell apart than others. Common scents like coffee and garlic are easy to name. Similar smells like sawdust and pencil shavings are often confused. This shows that olfaction works best with strong, distinct scents.
Smell and taste work together to help you identify food, and blocking one sense makes the other much harder to use. You blindfold three or more volunteers, have them plug their noses, and give each person small spoonfuls of different baby foods to name. After testing all the foods with noses plugged, you remove the plug and repeat. Comparing the two rounds shows clearly how much smell shapes taste — volunteers do much better once they can smell again.