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Valentine's Day Chemistry Mark as Favorite (10 Favorites)

LESSON PLAN in Chemical Change, Molecular Formula. Last updated February 10, 2022.


In this lesson, students learn about the chemistry of love. They see chemical structures of compounds involved in the biological process of love and learn about some of the chemical changes associated with love.

Grade Level

High or middle school


By the end of this lesson, students should be able to

  • Understand some of the chemistry involved with love

Chemistry Topics

This lesson supports students’ understanding of

  • Chemical changes


Teacher Preparation: 15 minutes

Lesson: 65 minutes (all four parts, each part’s estimate is listed below)

  • Show/discuss the Valentine PowerPoint (30 minutes)
  • Talk about Valentine gifts (5 minutes/Optional)
  • Relationship demos (20 minutes/Optional)
  • Valentine minute-to-win-it activities (10 minutes/Optional)


  • PowerPoint


No specific safety considerations need to be observed during this lesson.

Teacher Notes

  • I find that students love learning about the changes going on in their body when love is involved. They often share this information with their friends and family.
  • Some information included for the PowerPoint may be too mature for your students. The information is intended for the teacher’s background, and it’s up to them what they want to share with their students. All sources are provided, so teachers can cater the lesson to what they are comfortable sharing with their students.
  • Information for PowerPoint was compiled from the following sources. It would be helpful to review these sources and use information for PowerPoint discussion:
  • Background Information:
  • Love happens in three stages, and each stage involves different chemicals in the body.
    • Lust: testosterone, estrogen
    • Attraction: phenylethylamine, epinephrine, dopamine, serotonin, pheromones
    • Attachment: oxytocin, vasopressin, endorphins
  • Optional activities for students to demonstrate the love chemistry
    • oxytocin – allow students to give friends hugs if the friend agrees
    • pheromones – allow students to try on some cologne or perfume with pheromones
    • adrenaline – who thinks they are in love? Have students test with “love meter” (a handboiler)
    • PEA – give them each a piece of dark chocolate because it has PEA
  • Optional Valentine gifts
    • Love Apples – In olden days, women would put a peeled apple under their armpit and allow it to soak up pheromones. When a loved one went to war, the women gave the apple to the man so they could smell them.
    • Synthetic diamonds – Companies can make diamonds out of breath or ashes of loved ones.
    • Flowers – Buy white flowers. Spray them with phenolphthalein (don’t tell students). Show them the flowers, and share with them that you really want pink flowers. Spray with a basic solution (ex: 6 M ammonia), and they turn pink.
  • Optional Relationship demos
  • Minute-to-win-it activities:
    • Stack candy hearts – Put 15-20 in each bag and have students get in groups of twos. Measure the height in cm for each group. They can eat the hearts after.
    • Juju hearts – I draw four names from each class for this activity. I have lids to party pail ice cream that have a nice blue circle ring. Students bite of the tips of the hearts and make a circle and see who gets the furthest around in one minute.
    • Marshmallow toss – One partner has a plastic cup and the other stands on the other side of the room and tries to throw marshmallows into the cup.