Invisible ink, sometimes called ‘sympathetic ink’, is a way of writing secret messages. Spies have used invisible inks to pass on secret messages, as have prisoners and hostages. Invisible Messages…
Soap is made from animal fats and vegetable oils, mixed with a caustic chemical called sodium hydroxide (also known as lye). The sodium hydroxide reacts with the oil to make…
When an acid is mixed with a carbonate, a type of alkaline chemical, the two chemicals react and form the gas carbon dioxide. This can be quite dramatic! Making Gas…
New pennies and two pence pieces are bright copper, but after a while, they turn dull. This is because the copper reacts with oxygen in the air to form copper…
To grow crystals, you need to start with a saturated solution – water that has as much, sugar, salt or whatever crystal ingredient dissolved in it as it possibly can….
Chemistry uses chromatography to separate mixtures of chemicals. The word chromatography comes from the Greek words for ‘colour’ and ‘to write’. Paper chromatography is a simple form of chromatography, and…
Oil and water don’t mix – they are described as ‘immiscible’. Crude oil floats on the sea after a spill from a tanker. Motor oil shows up as a sheen…
Different parts of the country have soft or hard water. Hard water is water that has travelled through certain types of rock, including limestone, chalk and dolomite, and has forms…
