Two glasses of clear liquid sit side by side and look exactly the same. You tell everyone one of them is magic, and that your wizard light will say which. In the dark, one of them glows bright blue.
🌟 Level 1: Apprentice
⏱ 2 minutes to learn
🧪 Potions
🎒 Ages 6+
Works by itself, or one simple move. It works the first try.
🔆 Never shine it at anyone's eyes. A grown-up holds the light.🚫 A potion is for looking at, not for drinking.👋 A grown-up holds the UV torch and never points it at anyone's eyes. Tonic water is a grown-up's bitter drink, so this potion is for looking at, not tasting.
Magic tricks aren't superpowers, and that's what makes them amazing. A magician is a performer who uses skill, science and storytelling to make the impossible look like it just happened in front of you. The wonder you feel is completely real, though.
How do magicians do their tricks?
Magicians use secrets. Some secrets are hidden objects, some are special ways of holding things, and some are clever maths. The biggest secret of all is attention: a magician gets you to look at one thing while the secret happens somewhere else. Then they practise until it looks like nothing at all.
Two glasses of clear liquid sit side by side and look exactly the same. You tell everyone one of them is magic, and that your wizard light will say which. In the dark, one of them glows bright blue. It's a level 1 apprentice trick for ages 6 to 11 (grades 1st–5th), takes 2 minutes to learn, and needs 4 things you already have. Flick, the shop's rabbit, reads every step aloud with a picture, so a child can follow it alone, and one step is marked for a grown-up.
The secret
Tonic water has an ingredient called quinine in it, and quinine glows under ultraviolet light. Tap water doesn't, so the two look identical until the light goes on.
What you need
A clear glass or plastic cup
Water
Tonic water (a grown-up's bitter drink)
A small UV torch (a black light)
How to do it
Pour the water into one glass and the tonic water into the other.
Put them side by side and ask which one looks magic. Nobody can tell.
Ask a grown-up to turn the lights off or pull the curtains.
Grown-up step: A grown-up shines the UV light on both glasses, pointing it down at the table.
One glass lights up bright blue. Say your magic word and bow.
Magic words to say
“One of these is swamp water from a wizard's garden. The other came out of the tap. I can't tell them apart either, so let's ask the light.”
Pro tips
This is the best closer in the Potion Lab, because it needs the lights down and a dark room feels like an ending.
Line up three glasses and make the audience vote before you switch the light on.
No real flames anywhere near this one. A torch makes a far better spotlight anyway.
If something goes wrong
If nothing glows, the room isn't dark enough or the torch isn't really ultraviolet. Say "the magic needs more dark" and move somewhere with no windows.
Safety notes
Never shine it at anyone's eyes. A grown-up holds the light.
A potion is for looking at, not for drinking.
A grown-up holds the UV torch and never points it at anyone's eyes. Tonic water is a grown-up's bitter drink, so this potion is for looking at, not tasting.
Works best in the dark.
No fire, no flames and nothing sharp in a child's hand anywhere in the Magic Shop. Nothing ever goes in a mouth, a nose or an ear.
The science behind the trick
Quinine soaks up ultraviolet light, which human eyes can't see, and hands it straight back out as visible blue light. That's called fluorescence, and it's the same reason a white school shirt looks eerie at a disco.
What kind of trick is this?
🌈 Transformation. Something changes into something else. Almost every trick ever invented is one of eight kinds, and knowing which one you're watching is how magicians work out how a new trick is done.
The skill it teaches:The big finish. End on your best one, then stop. Perform it and it counts towards the Kitchen Alchemist badge.
Questions about the glowing water trick
Is magic real?
Magic tricks aren't superpowers, and that's what makes them amazing. A magician is a performer who uses skill, science and storytelling to make the impossible look like it just happened in front of you. The wonder you feel is completely real, though.
How do magicians do their tricks?
Magicians use secrets. Some secrets are hidden objects, some are special ways of holding things, and some are clever maths. The biggest secret of all is attention: a magician gets you to look at one thing while the secret happens somewhere else. Then they practise until it looks like nothing at all.