A garden full of flowers. A rotten egg. A piece of freshly baked bread. All of these things have strong smells. Do you know how we can smell them? We can smell things because they give off tiny molecules. These molecules float through the air, but they are invisible. Some of them end up in your nose. Inside the top of your nose, there are many tiny hairs. They connect to smell sensors. When the molecules land on the hairs, the sensors send signals about them to your brain. If you want to smell better, just sniff. That brings more molecules to your smell sensors. Smelling helps us in many ways. For one, it makes food taste better. Our tongues can only taste a few flavors. However, we can "taste" thousands more by smelling. Smelling keeps us safe too. For example, rotten food may have an unpleasant smell. Also, the smell of smoke warns us about fires. The next time you eat, concentrate on the smell of the food. Enjoy your sense of smell!

One day, Lauren Gauthier's dog, Victoria, was acting strange. She kept smelling a part of Lauren's nose. Then, she looked at Lauren. She did this over and over. Victoria seemed to smell something wrong. So, Lauren went to the hospital to check. Surprisingly, the doctors diagnosed her with skin cancer on her nose! How did Victoria know? Dogs have an excellent sense of smell. They have far more sensitive noses than humans do. In fact, their noses have around 220 million sensor hairs. In contrast, human noses only have around 5 million. Dogs also have a special organ for smelling. It is called a "Jacobson's organ." It's in the back of their noses. Humans don't have this. With this two-part system, dogs can pick out small odor differences. This lets them detect cancer in its early stages. They can find various types, including skin and lung cancer. They do this by smelling people's skin, breath, and more. Dogs aren't just our friends. They can also protect us from dangerous diseases.

You sniff an old favorite snack. Suddenly, you remember people, places, and things from long ago. We call moments like these "Proustian memories." Proustian memories are named after the French writer Marcel Proust. He wrote the novel In Search of Lost Time. In the story, the narrator tastes a madeleine cake. He dips it into tea and eats it. Then, he suddenly remembers something special. It's his aunt's old, gray house. Long ago, he ate madeleines and drank tea there. Eating the madeleine helps him remember that. Madeleines have a delicious smell of lemon and butter. The narrator smells it when he tastes one. Experts say some strong smells can help people recall events from the past. When molecules touch the hairs in your nose, sensors send signals to your brain. These signals go near the areas related to emotion and memory. Interestingly, other senses send signals elsewhere. Thus, smell has a more powerful effect on memory than any other sense does. Proustian memories can come from any smell. What smells make you remember the past?