WHAT IS THAT SMELL?

(4th grade, 20-30 min)

PURPOSE:

The student will discover and demonstrate the importance and effectiveness of scent as a communication tool for animals, including humans; the student will derive the significance of scent to the survival of species

Science TEKS (grade 4)

*Adaptations increase survival of members of a species 8a: identify characteristics that allow members of a species to survive and reproduce

MATERIALS:

film canisters (black) with lids (two per scent used)

cotton balls

various scents; liquids preferred, or solids w/x water

vanilla, peppermint, peanut butter, vinegar, root beer, tuna water, garlic, coffee, menthol, lemon, etc.

MOTIVATION:

The teacher will set a sample of a strong scent in a corner of the room before the activity is to be started and wait for a student to suddenly 'discover' it. Discuss with the students what the scent made them think of or words they would use to describe the scent. Students will probably segue into memories the scent causes them to recall. Lead into how animals use scents to remember where they have been, where their territory is, and have the students brainstorm for other reasons animals may use scent (i.e. prey, pheromones or mating searches, danger, weather patterns, etc.)

ACTIVITY:

Preparation entails simply placing a few drops of scent or solution onto cotton ball and placing it into the black film canister with a lid. The teacher will have already prepared enough vials so that there are only two for each scent, making sure each student has a vial. The students then must go in search of their mate, or match.

SAFETY TIPS :

Instruct the children that proper lab procedure for smelling is to waft, not inhale from directly over scent (this is especially important if cleaning agents are chosen as scents to be identified, or any strong scent such as vinegar, lemon juice, even garlic).

CONCEPT DISCOVERY:

Once the students have paired off, the teacher can question them on the secret identity of their scent. Students may indicate whether or not finding their partner was easy or difficult. Inquire whether this would be easier or more difficult outside, where many other scents might interfere with the hunt. Were there any scents that were close to another? How long did it take the student to differentiate between the similar scents? The instructor can then elaborate on insect pheromones and how animals communicate through scent. Be sure to discuss how this scent is transmitted and also picked up. Some students may connect dogs sniffing or sharks sensitive attraction to blood with this lesson.

GOING FURTHER:

The activity can be made more difficult by performing it outside, especially on a windy day. Having a strong scent of perfume in the room and then asking the students to differentiate between their various scents will also raise the difficulty factor. Projects related to pheromones and scents could be reports on perfume chemists jobs to determine scents which have psychological affects and elicit certain attitudes or memories.

CONNECTIONS:

Math: diffusion rates and concentration gradient calculations; time it takes for diffusion to occur

English: students can write adds for new perfumes using descriptive language; subliminal suggestion patterns used by advertisers; research Pavlov's dog experiment and the conditioning based on scent


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