Chemistry
Reactions you can watch happen. Here are all 25 working models in this field — each with a full build and working principle.
Lemon Battery Array
Wire lemons with zinc and copper electrodes in series to light a real LED from fruit.
Reaction Volcano
Baking soda and vinegar erupt on cue while you measure how the ratio changes the blast.
Elephant Toothpaste
A catalyst makes hydrogen peroxide erupt in a giant foam column in seconds.
Crystal Garden
Dissolve borax or salt in hot water and grow sparkling crystals on a string overnight.
Invisible Ink
Write a secret message in lemon juice that appears only when gently heated.
Red Cabbage pH Indicator
Boil red cabbage to make a natural indicator that turns rainbow colours across acids and bases.
Electrolysis of Water
A battery splits water into hydrogen and oxygen bubbles you can collect and compare.
Polymer Slime
Glue and a borax cross-linker turn liquid into stretchy slime — polymers you can hold.
Cold Pack Reaction
Mix two everyday chemicals and feel the cup turn icy — an endothermic reaction in your hand.
Copper Electroplating
Use electricity and a copper solution to coat a coin in a shiny new copper layer.
Rainbow Density Column
Stack liquids that refuse to mix into a striped tower sorted purely by density.
Marker Chromatography
Separate a single marker's hidden colours by letting water creep up paper.
Browning & Antioxidants
Test which kitchen liquids stop a cut apple from turning brown — oxidation you can slow.
Milk Plastic (Casein)
Curdle warm milk with vinegar and mould the solids into a hard, bone-like plastic.
CO₂ Candle Snuffer
Pour invisible carbon-dioxide gas over candles to put them out without touching them.
Naked Egg (Osmosis)
Dissolve an egg's shell in vinegar, then shrink or swell it to watch osmosis happen.
Sugar Rock Candy
Grow edible sugar crystals on a stick from a saturated syrup — sweet science you can eat.
Baking-Soda Stalactites
Two cups, some string and washing soda grow mineral spikes like a cave — just sped up.
Yeast & Sugar Balloon
Living yeast eats sugar and inflates a balloon with the gas it breathes out.
Hot Ice (Sodium Acetate)
A clear liquid freezes solid the instant you touch it — crystallisation on command.
Colour-Changing Milk
A drop of soap sends food colouring swirling across milk in bursts of motion.
DIY Acid Test
Use a cabbage indicator to count drops and compare how strong different acids are.
Galvanic Corrosion Race
Pair different metals in salt water and watch which one sacrifices itself to rust.
Homemade pH Strips
Soak paper in cabbage dye to make reusable test strips for any liquid you find.
Penny Cleaning Chemistry
A salt-and-vinegar bath strips tarnish off dull pennies and reveals an acid reaction at work.