It’s time to get messy! Here is one you definitely don’t want to do in your kitchen, take the experimenting outdoors.
You may have already seen or heard about the Coke and Mentos experiment. Basically you drop some Mentos in a bottle of Diet Coke and stand well back as it makes a big fizzy mess! First, you need to know what is going on. Fizzy drinks are just flavoured drinks that have a whole load of carbon dioxide gas dissolved into them. The gas stays trapped inside for as long as the lid is screwed on tight, when you take the lid off it will slowly come out as small bubbles. This is what makes the drink ‘fizzy’. If you’re a very patient person who really likes watching bubbles, you could sit and watch it for a couple of days while each bubble gradually makes its way out. I’m guessing that you would like something a bit more dramatic! By dropping things into the bottle, you can get all those bubbles to form at once and rush out of the bottle in a big fountain. The most famous example is the Mento but it is not the only contender for best fizz-producer. You can try out other sweets, salt, sugar, cake sprinkles…whatever you have in the cupboard. Try different drink brands and flavours, which is best? All of them work by the rough surface of the sweet providing ‘nucleation sites’, these are places where bubbles can easily form. Give them lots of nucleation sites and get lots of bubbles…simple!
Two very important things that you need to know: (1) This is an OUTDOOR experiment!!! It makes a big mess so make sure it is on the grass or somewhere that spillage doesn’t matter. (2) Only use sugar-free drinks, they simply work better (and don’t leave a horrid sticky mess that will attract every ant in the world to your garden). You might like to make a cardboard tube ‘launcher’ so you can drop several sweets in at once. Be warned it ‘erupts’ pretty quickly so stand back!
And … do this outdoors (did I mention that?).