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.

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

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

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 January 24, 2024 by Emma Vanstone

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