The Science of Making Butter

Bread and butter go together naturally (especially freshly made bread still warm from the oven). There are records of butter making from around 4000 years ago. Butter usually comes from cow’s milk, but it can also be made from milk from buffalo, camels, goats, sheep or horses. The Commercial Butter …

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Cleaning Tarnish Off Silver: Bicarbonate and Aluminium

After a while, even the best and most carefully polished silver becomes dull and tarnished, and needs to be cleaned again. Why does it tarnish, and how can it be made shiny again? Why Does Silver Tarnish? Silver reacts with the sulphur in the air to form silver sulphide. This …

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A Bending Bone

Unless it is something that has a soft and wobbly structure, like a jellyfish, all animals, including humans, have a stiff skeleton to support their muscles and other body tissues, help them move, and protect their internal organs from becoming damaged. Animals with a skeleton inside (known as an ‘endoskeleton’) …

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Making Hot Ice

Water solidifies or turns to ice at zero degrees centigrade. This experiment makes something that looks just like ice but forms at room temperature and gives off heat. The experiment involves heating solutions on the cooker hob – be very careful, and ask an adult to help if necessary. Making …

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Acids and Alkalis: Which Are Which?

The pH scale is a scale of numbers that describes how acid or alkaline (another word for alkaline is ‘basic’) something is. A pH indicator is a liquid or paper that changes colour – each colour corresponds to a number on the pH scale. Making an Indicator Solution To make …

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Making Polymers: Cornflour Slime and Silly Putty

Polymers are made of long molecules like chains that stick to each other (cross-link). Natural polymers include hair, wool and cellulose (in plants). Plastic is a synthetic polymer. ‘Silly Putty’ Silly Putty is the brand name for a polymer that bounces like a rubber ball, stretches when pulled slowly and …

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Making an Emulsion

Oil and water are described as immiscible liquids – liquids that do stay mixed together (see ‘Why Oil and Water Don’t Mix’). Even if oil and water are thoroughly shaken up, or whisked together, they will always separate out. An emulsion is a stable mixture of oil and water that …

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Make a Soda Fountain

Drinks are fizzy because they have carbon dioxide in them – the gas is forced into the drink at low temperatures and dissolves. Homemade fizzy drinks can be made using a SodaStream – watch the bubbles of carbon dioxide from the cylinder go into the water or you could try …

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Invisible Ink

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 and Heat Write a message using a cotton bud or a fine paintbrush and lemon juice. Let it dry and …

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Soap and Detergent Chemistry

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 soap. Detergents are generally made from synthetic compounds. How Do Soaps and Detergents Work? Washing clothes, hands or crockery and …

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