Smells Unit
Investigation I:
Speaking of Molecules
Lesson 1: Cat Food and Stinky Cheese
Lesson 2: Sniffing Around
Smells Unit – Investigation I
Lesson 1:
Cat Food and Stinky
Cheese
ChemCatalyst
• What does smell mean? Write a
definition.
• Why do you think we have a sense of
smell?
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
The Big Question
• How do we talk about smells?
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
You will be able to:
• Categorize smells.
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Activity
Purpose: This lesson introduces the
study of smell, which runs throughout the
unit as a theme. By the end of the lesson
you will be acquainted with five different
smell categories that are used for
identifying and grouping odors.
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
(cont.)
Safety Note: Any student having chronic
respiratory problems should not be
involved in the smelling portions of these
activities. Another student in the group
can act as that student’s “nose.”
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Sample
Substance
Smell Description
1
2
3
4
5
6
7
8
9
10
11
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Making Sense
• Smell classifications are general
terms that describe a group of smells.
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes
• Putrid is a word that describes things that
smell quite repulsive. Dead animal or really
old leftovers from the refrigerator smell
putrid.
• Camphor is a word used to describe things
that smell pungent and medicinal.
Camphor is a substance and a word used
back in your grandparents’ day. The smell
of camphor is quite distinctive. Bengay or
Vicks Vapor Rub smell like camphor.
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes (cont.)
• Sweet smells include things that are
flowery and fruity smelling.
• Minty is a green herbal smell that most
people are very familiar with and doesn’t
usually require explanation.
• Fishy smells are very distinctive and
don’t usually require an explanation.
Most seafoods smell fishy.
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes (cont.)
Minty
Fishy
Sweet
Putrid
Camphor
mint leaves
cat food
fruit Chapstick
Camembert
Blistex
Altoids
tuna
apple tea
gym socks
Vapor Rub
peppermint tea
sardines
rose water
sweat
eucalyptus
Juicy Fruit gum
perfume
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes (cont.)
• Wafting is a technique of using your
hand to draw air over the opening of a
container in the direction of your nose.
Air mixed with the substance is drawn
into your nose so that the smell from
the original substances is diluted.
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes (cont.)
Safety Note: In the chemistry laboratory
it is NEVER recommended to sniff from
a bottle directly, even if a substance is
presumed to be safe. It is expected that
students will use the wafting technique
from now on whenever they are asked to
smell anything in a chemistry classroom.
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes (cont.)
Vial A
Vial B
Vial C
Vial D
Vial E
minty
fishy
sweet
sweet
minty
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Check-In
Into which categories would you put the
following smells?
1) banana
2) peanut butter
3) rotten egg
4) shampoo
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Wrap-Up
• Scientists have come up with words to
classify smells, which include minty,
fishy, sweet, putrid, and camphor.
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Smells Unit – Investigation I
Lesson 2:
Sniffing Around
ChemCatalyst
• What do you think your nose is
detecting when it smells something?
What evidence do you have to support
your answer?
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
The Big Question
• What does chemistry have to do with
smell?
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
You will be able to:
• Predict how a molecule will smell
based on its molecular formula
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Activity
Purpose: In this lesson you will start to
explore the connection between
chemistry and smell. You will be given
the molecular formula and chemical
name of the five mystery substances that
you smelled in Lesson 1. Examine this
information in order to look for a
chemical relationship to smell.
(cont.)
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
(cont.)
Vial
Smell
Chemical Name
Molecular Formula
A
minty
l-carvone
C10H14O
B
fishy
phenylethylamine
C8H11N
C
sweet
amyl propionate
C8H16O2
D
sweet
isoamyl acetate
C7H14O2
E
minty
menthone
C10H18O
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Making Sense
• Is there any evidence that smell,
molecular formula, and chemical name
are related?
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Notes
Vial
Chemical
Name
Molecular
Formula
Predicted Smell
Actual
Smell
F
ethyl valerate
C7H14O2
sweet
sweet
G
butyric acid
C 4 H 8 O2
sweet, identical to
vial H,
putrid
or different from
the other two
H
ethyl acetate
C 4 H 8 O2
sweet
sweet
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Check-In
• How would you expect a molecule with
the molecular formula C8H16O2 to
smell? Explain.
© 2004 Key Curriculum Press.
Unit 2 • Investigation I
Wrap-Up
• Smell appears to be related to
molecular formula and chemical name.
• Molecular formula alone is not always
sufficient to predict smell because
molecules can have the same
molecular formula but different smells.
© 2004 Key Curriculum Press.
Unit 2 • Investigation I