The pH scale
Acids and bases are at opposite ends of the pH SCALE, and this word search gathers the chemistry. You'll be finding the two extremes — the sour ACID and the soapy BASE or ALKALI — plus the NEUTRAL point in the middle, and the way we test them with LITMUS and a UNIVERSAL INDICATOR.
Each puzzle pulls a fresh selection from the list, so the chemistry set changes every time you play — gentle on Easy, and a Hard-mode challenge once the diagonals and backwards words appear.
Everyday chemistry
Acids and bases are all around us, and the words are here. Acids taste SOUR — think VINEGAR and LEMON — and a STRONG one like SULFURIC acid is CORROSIVE. Bases feel slippery — like SOAP, BLEACH and AMMONIA. We've hidden the lab words too: the chemical REACTION between them, the SOLUTION you DILUTE, the HYDROGEN that makes an acid acidic, and the BITTER taste of a base.
What the pH scale really measures
The pH SCALE runs from 0 to 14, and the number tells you how much HYDROGEN an acid has let loose in a SOLUTION. A low number means a STRONG ACID — battery acid and SULFURIC acid sit near the bottom — while a high number means a STRONG ALKALI like BLEACH, oven cleaner or AMMONIA. Pure water sits right in the middle at 7, perfectly NEUTRAL, which is why it's the fairest thing to DILUTE a chemical with.
The clever part is that you can see all this with colour. LITMUS paper turns red in acid and blue in alkali, and a UNIVERSAL INDICATOR goes a whole rainbow from red through green to purple, giving you the exact pH at a glance. It's not just lab work, either: gardeners test soil pH to keep plants happy, and your stomach uses a CORROSIVE acid to break down food — neutralised by an antacid, a mild BASE, when it gives you heartburn.
Great for a chemistry topic
It pairs perfectly with a science lesson on the pH scale and how we test acids and bases — Easy mode keeps the grid small with no diagonals or reverse words. Play online, print a PDF pack, or use our Make Your Own tool to build a grid from your own chemistry words.