Make a Vacuum Cleaner

Originally, carpets and rugs were cleaned by lifting them, taking them outside, hanging them over a line and beating them with a carpet beater (a very dusty job), or by using a stiff brush and dustpan. Vacuum cleaners have made cleaning carpets so much quicker and easier by sucking the …

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Seeing Ultraviolet Light: Tonic Water in Sunlight

Ultraviolet (UV) light is an invisible part of light. It has a shorter wavelength than violet light (see ‘Making a Rainbow: Breaking Light Into Colour’), and its name means ‘beyond violet’. Ultraviolet light is divided into three types – UVA, UVB and UVC. Sunlight includes all three types of ultraviolet …

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Growing Stalactites and Stalagmites

Stalactites and stalagmites are formations of rock in underground caves. They are formed when calcium carbonate and other minerals dissolve in water running through the soil and rocks. As the water runs down into the cave and drips from the roof, it leaves some of the minerals on the roof, …

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Melting Points for Different Solids

Different solids turn into liquids (melt) at different temperatures. This temperature is described as the melting point. Some solids are made up of molecules that bind together tightly and others are made up of molecules that bind together loosely – the tighter the binding, the higher the temperature needed to …

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The Physics of Bubbles

Whether they are in a bubble bath or drifting on the wind, bubbles are beautiful and fun things. Try making your own to examine the amazing properties of the simple bubble. Making Bubbles To make bubbles, you need a bubble solution and a wand. A basic bubble solution is water …

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Static Electricity: Making Things Stick

Atoms (the tiny building blocks that make everything) contain protons, which have a positive charge, and electrons, which have a negative charge. Some electrons are fixed onto the atoms quite loosely, and can come off quite easily when two different materials are rubbed together, and transfer from one surface to …

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Detecting Fake Silver: Conductivity of Metal

Heat travels in three different ways – conduction (heat travelling through a solid), convection (heat travelling through liquids and gases) and radiation (heat travelling through empty spaces). Detecting Fake Silver: Heat Conductivity in Metal To find out if a spoon is real silver, put it in a mug with a …

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Bending Light: Disappearing Glass Bowl and Bending Pencil

As light passes through transparent objects, it bends. This can create optical illusions like disappearing bowls, bending pencils and mirages. This is called refraction, and is useful in magnifying glasses and spectacles. Disappearing Glass Fill a glass bowl with cooking oil (it can still be used afterwards) and gently lower …

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Solids, Liquids and Gases: Ice, Water and Steam

Water exists in three states – solid ice, liquid water and gaseous steam. Solids have a fixed shape and size. Liquids can change in shape, but have a fixed size. Gases can change shape and size. Ice Water freezes at 0 degrees Centigrade and becomes ice. On a cold, dry, …

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Keeping Warm or Cold: Insulation and Conduction

Heat travels through solids by conduction (see also ‘Detecting Fake Silver: Conductivity of Metal’). Insulation can keep things warm and keep things cool by reducing heat transfer through conduction. Insulation can also help reduce heat loss through convection (the way heat travels through liquids and gases) and radiation (the way …

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