Fragrance Notes: Top, Heart & Base
A fragrance changes because its ingredients evaporate at different speeds: light top notes arrive first, heart notes follow, and heavy base notes linger.
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Why does the same perfume smell different an hour after you spray it?
- fragrance-pyramid
- A structure that describes how a perfume unfolds: top notes, heart notes, and base notes.
- molecular-weight
- Molecules in fragrance ingredients differ in size and weight; lighter molecules tend to escape more easily.
- volatility
- A measure of how easily a molecule escapes into the air; the higher the volatility, the sooner it reaches your nose.
- top-notes
- The first impression: light, fresh, highly volatile molecules that fade within about 15 minutes.
- heart-notes
- The character of the fragrance: moderately volatile molecules that appear after the top notes fade and last for hours.
- base-notes
- The foundation: heavy, low-volatility molecules that linger for hours or even days.
- time-unfolding
- The perceived scent changes over time because different molecules evaporate and arrive at the nose at different rates.
A scent smells different over time only because your nose gets used to it.
Explain that evaporation of different-sized molecules is the main driver; smell adaptation is only a small part.
Top notes are the strongest part of a perfume.
Clarify that top notes are simply the most volatile; they create the first impression but are not the most powerful or long-lasting.
All perfume ingredients evaporate at the same speed.
Show that molecular size and volatility vary widely, so ingredients reach the nose at different times.
- perfume manufacturing and formulation
- skin chemistry and body chemistry variations
- synthetic versus natural ingredient chemistry
- Explain why top notes appear before heart and base notes
- Identify whether an ingredient is likely a top, heart, or base note based on its character
- Use the fragrance pyramid to predict how a perfume will evolve on skin
- When you encounter a new perfume or scented product, predict how its scent will change over time by looking at its note list.
General learners curious about perfume or scent; no chemistry background required.
- 01Why Does Perfume Change?slideOrientationObserve
Welcome learners and pose the central question of the course.
- A single fragrance can smell different over minutes and hours
- Opening question: what causes the change?
- What we'll explore: scent pyramid, evaporation, choosing perfume
- 02Your First GuessquizPredictionChoose
Let learners commit to an explanation before the science is revealed.
- Choose the explanation that seems most likely
- Keep your answer in mind as the course unfolds
- 03The Fragrance PyramidslideModel buildingObserve
Introduce top, heart, and base notes as the classic structure of a fragrance.
- Three layers recorded in a fragrance pyramid
- Top notes: bright and fleeting
- Heart notes: the character of the scent
- Base notes: the lasting foundation
- [Table] Typical ingredients and duration for top, heart, and base notes
- 04The Evaporation RaceinteractiveMisconception repairObserve
Explore how molecules of different sizes escape at different speeds and reach your nose at different times.
- Adjust molecular size and watch evaporation
- Notice which notes disappear first
- Bigger molecules stick around longer
- 05Why Size MattersslideModel buildingObserve
Connect evaporation speed to molecular weight and explain why lighter molecules reach the nose first.
- Volatility: how easily a molecule escapes the liquid
- Small, light molecules evaporate quickly: citrus, herbs, light florals
- Large, heavy molecules linger: musk, woods, vanilla
- The nose perceives these arrivals as top, heart, then base notes
- 06Check Your UnderstandingquizPracticeChoose
Test the core idea that volatility, not strength or nose fatigue, controls when notes appear.
- Identify why top notes fade first
- Distinguish top, heart, and base ingredients
- 07A Perfume's Life on Your SkinslideApplicationApply
Apply the pyramid to a real wear-time timeline and practice predicting how a scent will evolve.
- 0-15 minutes: top notes greet you
- 15 minutes to 2 hours: heart notes take over
- 2 hours and beyond: base notes linger
- Look at a note list and predict which notes will last longest
- [Chart] Line chart: perceived intensity over time for top, heart, and base notes
- 08The Story of a ScentslideSynthesisExplain
Pull everything together: perfume changes because it is a sequence of evaporating molecules, not a single static smell.
- Evaporation turns a fragrance into a story
- Each layer is a cast member with an entrance and exit
- Use volatility to explain the whole timeline
- 09Fragrance Notes CheckquizAssessmentChoose
Assess understanding by applying the ideas to a new fragrance scenario.
- Apply the pyramid to a new scent
- Choose the best explanation for why some notes last longer
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