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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Warm and Cold: Heavy Water

Hot water has more energy than cold water. This makes the water molecules move around more. Molecules that move more take up more space, but still weigh the same, so cold water is denser than hot water. The denser cold water sinks and the less dense hot water rises (see …

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Warm and Cold: Expanding Air

As air gets warm, the air molecules have more energy and move around more, taking up more space. As the warm air expands, it becomes less dense (see ‘Floating and Sinking: Looking at Density’) than the cold air, so rises up and floats above the cold air. Water acts in …

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Action and Reaction: Balloons in Flight

Sir Isaac Newton was born in 1643 and died in 1727. He was a physicist, mathematician, astronomer, biologist and chemist. Newton developed three laws of motion, which described how things move in response to forces (things like ‘pushes’ or ‘pulls’). Newton’s Third Law states that, “to every action there is …

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Pulling and Pushing: Magnetic Attraction

Magnets are attracted to some metals, and can attract and repel each other. The earth has a magnetic field, and so magnets can be used to find directions. Magnets and Magnets Magnets attract or repel other magnets. Put a bar magnet on a table and move the end of another …

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Friction: Keeping Warm and Keeping Rolling

Friction is the force that acts between two moving surfaces and tries to stop them moving. Friction can be between two solids, a solid and a liquid, or a solid and a gas. The amount of friction between solid surfaces depends on the weight of the objects and the roughness …

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