Science Fair Projects - How good is a person's sense of smell?

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Smell (Olfaction)

Many of the experiments detailed below require that a blindfold be used. Keep in mind that some people do not like to be blindfolded...you could ask them to keep their eyes closed, but don't count on them having their eyes closed for a very long time. Also, some people are very sensitive to smells, so be careful. See "The Nose Knows" for background information on the sense of smell.

Expose Your Nose

For grades K-6

We can recognized a wide variety of smells. Some smells can stir up memories. To demonstrate the sense of smell (olfaction), collect several items that have distinctive smells such as:

lemon     orange peel      cedar wood     perfume soaked cotton
banana    pine needles     chocolate	  coffee
dirt 	  vanilla	   garlic	  onion    
mint	  vinegar	   moth balls	  rose flowers
saw dust  ginger           peppermint     pencil shavings

Keep the items separated and enclosed in plastic containers so that the odors do not mix. Put a blindfold on a student (or punch holes in the top of the containers to eliminate the need of a blindfold) and ask the student to:

Questions and Comparisons

Identify the item by smell.
Rate the odor (strong, pleasant, neutral, [bad or good for young kids])
Tell about any memories associated with the smells.

Materials:

Smells: lemon, orange peel, cedar wood, perfume, banana, pine, etc.
Blindfold or container to hold the smelly items

Use only small amounts of each item and instruct students to take only small whiffs from each container. Be especially careful with perfume and moth balls.

Take a Walk on the Smelly Side
For grades K-6
Plan a trip outside. The trip could include places around a school. You could visit the cafeteria, the library, the main office, a garden, or the playground. As you take the walk, write down all the smells you find. When you get back to class compare the smells that you found with those found by other students.
Materials:

None

Smell Match
For grades K-6
Collect pairs of items that smell and place them in containers that you cannot see through. Poke holes into the top of the containers. Mix up the containers and try to match the containers that have the same item. When you have made your decisions, open up the containers and see how you did.
Suggested smells:

lemon orange peel cedar wood perfume soaked cotton banana pine needles chocolate coffee dirt vanilla garlic onion mint vinegar moth balls rose flowers

How Sweet It Is
For grades 3-12
We know that the nose can identify a wide variety of smells. How sensitive is your sense of smell? Collect various dilutions of a cologne, perfume or even a fruit juice with a strong smell. Cologne or perfume works well because it is concentrated. Add a few drops to a plastic container (like a washed 8 oz. yogurt cup) and fill the remainder of the container with a set amount of water (for the yogurt cup, add 4 oz. of water). In the next container, add a few more drops of perfume than you had in the first container and add the same amount (4 oz.) of water. MAKE SURE YOU KEEP TRACK OF WHICH CONTAINER HAS THE MORE CONCENTRATED SOLUTIONS, but do this on a separate piece of paper. For example, mark a container with a letter or number or symbol and "code" it by the number of drops of perfume on a "secret" piece of paper. Make at least 5 samples with varying concentrations of odor. Now for the experiment...mix up the "order" of the solutions and ask students to rate which samples have the strongest (most pungent) odors. Depending on what you are using to create the smells, you may have to experiment on yourself to get the best different concentrations. Keep track of where mistakes are made.
Questions

Are mistakes made in the same place of the "concentration gradient"?
With repeated attempts to rate the concentration, does the performance get better or worse?
Are the first samples "easy" to smell the later samples? Is there any adaptation of the sense of smell?
Materials:

Smells: perfume
Container to hold the smelly items (or a blindfold of the diluted solutions are different colors
Water for dilutions

Smell Cards
For grades K-6
A bit like "scratch and sniff" cards, these smell cards could be used for memory or matching type games. Collect a number of dried herbs, spices or flowers that have a strong smell. Glue some of your "smelly" items on index cards or cardboard. Make sure that you don't completely cover the "smell" with glue.
Materials:

Smells: dried herbs (oregano, basil, rosemary, etc), spices (cinnamon, etc.) and flowers
Paper: cardboard or index cards
Glue

You Smell! Really, you do.
For grades 3-12
Each person has his or her individual smell...we smell different from one another. It is a bit like a fingerprint. I suppose you could call it a "smell print." You might find this experiment a bit gross, but you might find the results surprising. Get three identical, clean T-shirts that have already been washed. Mark one with an "X" behind the shirt tag. Wear one for a few hours (and try not to get it too dirty). Then get the other two T-shirts and mix them up with the one your wore. Now using your sense of smell, find the one that you wore. Ask someone else if they can tell which T-shirt you wore.
You could also give the T-shirts to three different people. Have them wear their T-shirts for a few hours. Take the T-shirts and have each person try to identify the one they wore. See if each person can match the T-shirt with the person who wore it.
Materials:

Three identical T-shirts (or other type of shirt).

Complete lesson plan on olfaction with Teacher Resource, Teacher Guide and Student Guide.