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Home » Primary Science » Key Stage 1 Science » Valentine’s Day Science Experiments and Activities for Kids

Valentine’s Day Science Experiments and Activities for Kids

Modified: Feb 11, 2025 · Published: Jan 23, 2024 by Emma Vanstone · This post may contain affiliate links · 35 Comments

Valentine’s Day is coming around quickly; whether you celebrate or not, you’ll LOVE this collection of Valentine’s Day science experiments. Make a Skittles heart, a paper aeroplane delivery system, colour-changing love potions and lots more!

Valentine’s Day Science Experiments

Heart Patterns

First up are super simple heart patterns. Cut out different colours and sizes of hearts and use them to make heart patterns. If you want to mix it up, add some flower shapes too!

Heart shapes are also great for practising cutting and those important fine motor skills.

Make a fizzy love potion

These colour changing love potions are fantastic fun. The use of red cabbage indicator means the colour of the potion changes when an acid or alkali is added!

The potions below are made with red and pink food colouring, baking soda, vinegar and red cabbage indicator.

Fizzy potions made with baking soda, vinegar and red cabbage indicator. The potions are in glass containers and red, purple and pink coloured.

Blow up a heart 

Try blowing up a balloon with a heart drawn on it or even a heart-shaped balloon using the fizzy power of an effervescent tablet or baking soda and vinegar.

The reaction between the effervescent vitamin tablet and water produces carbon dioxide gas, which fills the jar and then the balloon, causing it to inflate.

Pink balloon with a heart drawn on it on top of a small glass container containing alka seltzer and water for a Valentine's Day science experiment
Blow up a balloon with Alka Seltzer

Coloured Valentine Flowers

Create pretty flowers for your Valentine with this super simple transpiration experiment. All you need to do is buy some white flowers and place them in a mixture of food colouring and water for a few hours. The petals change colour as the coloured water travels up the stem into the petals!

A white flower with blue tips on the petals after being left in a mixture of food colouring and water

Respiration Pizza

Does anyone want a heart-shaped pizza? This is a great activity for learning about respiration as yeast is used to make the dough rise.

Pizza dough in a silver bowl for a respiration activity.
Respiration – pizza dough

How fast does your heart beat?

Learning about heart rate and how it changes with exercise with a simple heart rate investigation.

Child running in a field for a heart rate science experiment
Heart rate investigation

Where is the heart?

Ask children to draw around themselves on a large piece of paper and draw their heart in the right place.

Child lying on a long sheet of paper to be drawn around for learning about different parts of the body

Make your own stethoscope

Make a stethoscope and listen to a friend’s heart beating. Spiderman dress-up is optional!

Children testing a homemade stethoscope - Science for Kids
Homemade stethoscope

Pumping Heart Model

Older children can make a clever pumping heart model. This is a great way to demonstrate how heart valves work.

pumping heart model made with a jar, straw and balloon

Valentine Candy Science

Make a beautiful coloured heart with skittles or M&Ms. Create a pattern on a white plate or tray and pour warm water over the top. The colour from the Skittles spreads into the water, giving a rainbow effect.

Skittles on a plate in a heart shape. Water has been poured over the skittles and the colour from the sweet has spread through the water.

Or how about building a tower of candy using Valentine’s sweets and toothpicks?

Secret Valentine Messages

Send a message with flowers

Write a message inside a paper flower, fold up the petals, and then place in water to watch the message appear.

magic opening flowers valentine style

Messages with lemon juice

Did you know you can write secret messages with lemon or lime juice?

Secret Messages - Science for Kids

Scratch Art Pictures

We had a lot of fun making scratch art canvas pictures. Oil pastels work really well for this activity, as the black oil pastel gives a thick coating that can be easily scratched off.

Scratch art message for Valentine's Day
Scratch Art Messages for Valentine’s Day

Once you’ve made your secret message, create a delivery system for it. This could be a paper plane, parachute, zip line or even a motorized car.

STEM Challenge for Valentine's Day - make a delivery system for a Valentine message

Free Valentine’s Day Science Experiment Pack

Download my FREE Valentine’s Day science experiment pack! The pack includes four science experiment instructions, templates, and STEM challenge cards!

  • Blow up a heart balloon
  • Make Valentine spinners
  • Magic opening flowers
  • Straw rocket messages
Valentine’s Day Science Experiment Pack
Valentine's Day Science Experiments

Little Bins for Little Hands has some gorgeous crystal hearts to make and a beautiful heart lava lamp.

Red Ted Art has some brilliant Valentine’s Day resources for teachers and parents as well.

Don’t forget to take a look at my Valentine’s Day STEM challenges, too!

Do you have any more Valentine’s Day Science ideas for us?

Collage of easy Valentine's Day science experiments and investigations for kids.

If you didn’t find what you were looking for here, take a look at my other easy science experiments!

Collage of Valentine's Day themed science experiments. Pink fizzy potions, a heart balloon, skittles heart and oil pastel pictures.

Last Updated on February 11, 2025 by Emma Vanstone

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Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

Comments

  1. Mum of One

    January 16, 2014 at 9:16 am

    What a great selection. I HAVE to try the transpiration one, that is amazing! Am pinning 🙂

    Reply
  2. Hellie's Corner

    January 16, 2014 at 9:19 am

    I’m with you on the not doing valentines day! Great idea though, to turn it around to learning about the heart.

    Reply
  3. Abby Boid

    January 16, 2014 at 9:29 am

    I absolutely love your site. It is one of my most favourite of finds in a while. When I get on top of Facebook and google+ I look forward to following you there. In the meantime, see you here again soon.

    Reply
  4. Amanda

    January 16, 2014 at 9:34 am

    Oh wow, these are great!! I shall be showing these to my husband tonight to see if we can do any of them with our toddler 🙂

    Reply
  5. Emma (My Little 3 and Me)

    January 16, 2014 at 11:03 am

    As ever Emma your ideas are just super. Lots to keep us busy on the build up to Valentine’s Day, thank you.

    Reply
  6. Mummy of Two

    January 16, 2014 at 11:04 am

    Some great ideas. We don’t usually do much for valentines either but would be nice to try a few of these with my eldest.

    Reply
  7. natalie

    January 16, 2014 at 11:18 am

    Some lovely ideas. Not that we usually do anything, although I love how you’ve involved the kids.

    Reply
  8. Laura @ Kneadwhine

    January 16, 2014 at 11:20 am

    These are brilliant ideas – I’d forgotten about the flower/food dye experiment. Must do that with D!

    I’m glad to have found you – sure I’ll be doing some pinning!

    Reply
  9. Michelle

    January 16, 2014 at 11:45 am

    Some very cute ideas!

    Reply
  10. Sim @ Sims Life

    January 16, 2014 at 12:23 pm

    Aww some fab ideas and I will definitely be trying these out with mini me!! I absolutely hate Valentine’s Day 🙁 x

    Reply
  11. Ali at kidschaos.com

    January 16, 2014 at 12:53 pm

    some darling ideas there Emma, we’re looking forward to reading more about the baking soda heart!

    Reply
  12. Donna @ Little Lilypad Co

    January 16, 2014 at 12:56 pm

    For someone that doesn’t really do Valentines, you have some “love”ly ideas 🙂

    Reply
  13. Mammasaurus

    January 16, 2014 at 1:04 pm

    oooo one with flowers! Kitty would love that – off to look!

    Reply
  14. maggy, red ted art

    January 16, 2014 at 1:29 pm

    Wow! So many great ideas! Love them!

    Reply
  15. Boo Roo and Tigger Too

    January 16, 2014 at 1:31 pm

    The coloured flowers is amazing *wonders if Mr Boo will treat me to flowers any time soon*

    Reply
  16. Alice

    January 16, 2014 at 1:35 pm

    I’m bookmarking these… we are a big fan of hearts in this household and my little one will love so many of these activities!

    Reply
  17. Fritha Strickland

    January 16, 2014 at 1:44 pm

    I love the transpiration idea! so pretty! x

    Reply
  18. Lori

    January 16, 2014 at 1:47 pm

    I always love a bit of science 🙂 but I’m a total hearts and flowers type of girl when it comes to Valentines Day. I think we might try the flowers and glittery heart combo for the 14th 🙂 Thanks for sharing x

    Reply
  19. Hannah Staveley

    January 16, 2014 at 2:00 pm

    That’s is so good I just love this .x

    Reply
  20. Laura Halls

    January 16, 2014 at 3:57 pm

    What a fantastic alternative

    Reply
  21. Jennifer

    January 16, 2014 at 4:25 pm

    What great ideas! That pizza looks so yummy 🙂

    Reply
  22. Aisha from expatlog

    January 16, 2014 at 4:54 pm

    Some great ideas – I want to try the transpiration one too 🙂

    Reply
  23. Charly Dove

    January 16, 2014 at 6:42 pm

    Gosh so many brilliant ideas! Our toddler would love to do most of these 🙂

    Reply
  24. Vicky

    January 16, 2014 at 6:44 pm

    What fun ideas! I’m not really a hearts and flowers idea, but I love finding new themed crafts and activities to do with the kids, so I know we will be making heart shaped pizza! Mmmm….mmmm!

    Reply
  25. Twinsplustwo

    January 16, 2014 at 8:34 pm

    Some really good ideas. I wish I could have benefitted from your Blog when my children were younger, will share it with my HE friends too.

    Reply
  26. Cass (@frugalfamily)

    January 16, 2014 at 8:40 pm

    I love your ideas – they’re fab x x

    Reply
  27. Kirsty

    January 16, 2014 at 9:19 pm

    What a great round-up! Pinned for later and shared 🙂

    Reply
  28. Louisa

    January 17, 2014 at 1:37 pm

    I really must try changing the colours of flowers (for my own entertainment, not the kids)!

    Reply
  29. Corinne Jacob

    February 18, 2014 at 7:10 am

    Awww man, I wish I had found this earlier! It’s not too late to have a post Valentine’s weekend. Is it? 😀

    Reply
  30. Willie

    March 08, 2017 at 5:32 pm

    Yeah, that’s the tiektc, sir or ma’am

    Reply
  31. Liza

    March 08, 2017 at 9:07 pm

    Fif > &la&no; Iguorantqnbsp;» tout seul dans un message, ce n’est pas très utile non plus et cela, n’apporte rien au débat

    Reply

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