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.
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.
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!
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.
How fast does your heart beat?
Learning about heart rate and how it changes with exercise with a simple 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.
Make your own stethoscope
Make a stethoscope and listen to a friend’s heart beating. Spiderman dress-up is optional!
Pumping Heart Model
Older children can make a clever pumping heart model. This is a great way to demonstrate how heart valves work.
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.
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.
Messages with lemon juice
Did you know you can write secret messages with lemon or lime juice?
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.
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.
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
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?
If you didn’t find what you were looking for here, take a look at my other easy science experiments!
Last Updated on February 11, 2025 by Emma Vanstone
What a great selection. I HAVE to try the transpiration one, that is amazing! Am pinning 🙂
I’m with you on the not doing valentines day! Great idea though, to turn it around to learning about the heart.
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.
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 🙂
As ever Emma your ideas are just super. Lots to keep us busy on the build up to Valentine’s Day, thank you.
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.
Some lovely ideas. Not that we usually do anything, although I love how you’ve involved the kids.
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!
Some very cute ideas!
Aww some fab ideas and I will definitely be trying these out with mini me!! I absolutely hate Valentine’s Day 🙁 x
some darling ideas there Emma, we’re looking forward to reading more about the baking soda heart!
For someone that doesn’t really do Valentines, you have some “love”ly ideas 🙂
oooo one with flowers! Kitty would love that – off to look!
Wow! So many great ideas! Love them!
The coloured flowers is amazing *wonders if Mr Boo will treat me to flowers any time soon*
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!
I love the transpiration idea! so pretty! x
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
That’s is so good I just love this .x
What a fantastic alternative
What great ideas! That pizza looks so yummy 🙂
Some great ideas – I want to try the transpiration one too 🙂
Gosh so many brilliant ideas! Our toddler would love to do most of these 🙂
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!
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.
I love your ideas – they’re fab x x
What a great round-up! Pinned for later and shared 🙂
I really must try changing the colours of flowers (for my own entertainment, not the kids)!
Awww man, I wish I had found this earlier! It’s not too late to have a post Valentine’s weekend. Is it? 😀
Yeah, that’s the tiektc, sir or ma’am
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