to the British Science Association

We are a registered charity that exists to advance the public understanding, accessibility and accountability of the sciences and engineering in the UK.


Show me content for... +

Show me content for...
Professional development
Families & teenagers (aged 12+)
Families (children aged 12 & under)



Register with us and you can....

  • Sign up to our free e-communications
  • Become a member of the Association
  • Create your own web account, & post comments
  • Be part of British Science Festival
  • Save your favourite items


Keep up to date with the latest news from the British Science Assocation. Sign up to our RSS feeds and take us with you when you are on the move.

You are here

Get involved

Choose from...

What's happening in your area?

National Science & Engineering Week and KABOOM! present

This is your quest for mess!

The mentos fountain challenge is based around the "diet coke and mentos fountain": a reaction between a carbonated beverage and Mentos sweets that causes the beverage to spray out of its container. Your challenge is to create the highest possible fountain using nothing more than mentos, diet cola and pure brain power!

What you'll need

For each fountain:

  • 1 2-litre bottle of diet cola (for example, Diet CokeTM)
  • 1 pack of mentosTM
  • 1 camera with sports mode or video camera
  • An open space that's okay to get messy!

The basic experiment

  1. Carefully open your bottle of diet cola.
  2. Begin recording with the video camera or be ready with the regular camera set to sports mode.
  3. Take 4 mentos and drop them in the bottle.
  4. Step back!
  5. Observe your glorious fountain!
  6. Now for the science bit: change one thing at a time and if it makes a bigger fountain!
  7. Email a YouTube link or photos of your best results to mentos@britishscienceassociation.org 

Download the challenge leaflet here:

Mentos Fountain Challenge Leaflet

Things to try

The mark of a true scientist is performing fair tests - changing one thing at a time to see how it affects your results. Here are just a few things you might like to think about to increase the height of your fountain:

  • Does warm or cool diet cola work better?
  • Would a bigger or smaller bottle neck be good?
  • Are the mentos better whole or in pieces?
  • Does shaking the bottle improve the results?

The science behind the fountain

Click here to learn about the science behind the fountain!


From the chemistry of gunpowder to the anatomy of high explosive detonations, the dissection of an internal combustion engine and the might of the hybrid rockets that launch man into space, KABOOM! uncovers the science behind the explosions that shape out modern world. Find out more at www.gregfoot.com/kaboom.

National Science & Engineering Week is a programme of science, engineering and technology events across the UK aimed at people of all ages. Anyone can organise an event or activity, from schools to community groups and from parents to large organisations. The resulting programme of over 4500 events and activities is a hugely varied and eclectic celebration of science. Visit www.nsew.org.uk for more information.