Get ready to spread some science joy into your St. Patrick's Day celebrations. If you've ever wondered how rainbows form or how to build a bridge strong enough to hold a pot of gold, you're in the right place!
Put on your thinking cap, grab some basic materials and have the best St Patricks Day ever!
What is St. Patrick's Day?
St. Patrick's Day is a celebration of the patron saint of Ireland. It has a deep history that blends religious tradition with a touch of folklore! St. Patrick's Day is celebrated on the 17th March, which is thought to be the anniversary of St. Patrick's death in 461 AD.
Rainbows and Gold
In Irish folklore, leprechauns are the bankers of the fairy world. They mend shoes and get paid with gold coins. Legend says they hide their coins in pots of gold at the end of the rainbow!
Ireland usually has a lot of rain showers in March, which makes it the perfect time to see a rainbow!
Make a rainbow
Give my Make a Rainbow STEM Challenge a go and create your own rainbow using a hosepipe.
Rainbows are a great way to learn about refraction and dispersion.
Walking Rainbow
Leprechauns need a rainbow to find their gold. You can make one using food colouring, water and kitchen towel. Sometime called a walking water demonstration, it's a great way to demonstrate capillary action.
Set up 6 jars or clear containers in a circle. Fill three with water and either red, yellow or blue ( primary colours ) food colouring and leave the ones in between empty.
Water moves through the tiny gaps in the paper towel to fill the empty jats, creating the colours of the rainbow.
Filter Paper Rainbow - Chromatography Challenge
Learn about a separation technique called chromatography with filter paper and coloured washable felt tips!
If you use felt tip pens in the same colours as the rainbow, you'll create a rainbow effect on the filter paper.
Clean Leprechaun Coins
Find the best way to clean the leprechaun's coins using vinegar, salt and water! This is a fantastic kitchen chemistry experiment that should leave you with sparkly coins with too much effort.
Do you have any more St. Patrick's Day STEM Challenge ideas for us?
Last Updated on March 18, 2026 by Emma Vanstone
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