Blastoids are an extinct type of stemmed echinoderm, often referred to as sea buds. They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississippian subperiod of the Carboniferous period. However, blastoids may have originated in the Cambrian. Blastoids persisted until their extinction at the …

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Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, …

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Van Stadens Wind Farm

Construction on Van Stadens Wind Farm outside Port Elizabeth in the Eastern Cape, was started in September 2012. The South African renewable energy company, MetroWind, is proceeding with the R550-million project which will provide power to the Nelson Mandela Bay municipality. The company will construct nine 3-megawatt wind turbines, boosting the local electricity grid, accounting for nearly half the 10 percent renewable energy …

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The Sun is the central star of the Solar System. It is a nearly perfect ball of hot plasma that has been heated to incandescence by nuclear fusion processes in its center and radiates energy mostly as visible light, ultraviolet light, and infrared radiation. It is by far the most essential source of energy for …

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The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth’s water. Another definition is “any of the large bodies of water into which the great ocean is divided”. Separate names are used to identify five different areas of the ocean: Pacific (the largest) Atlantic, Indian, Southern (Antarctic), and Arctic (the smallest). Seawater covers approximately 361,000,000 km2 (139,000,000 sq mi) of the …

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Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from Greek: κηρός (keros) meaning “wax”, and was registered as a trademark by Canadian geologist and inventor Abraham Gesner in 1854 before evolving into a generic trademark. It is sometimes spelled kerosine in scientific and industrial usage. The term kerosene is common in much …

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Paraffin wax

Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal or oil shale that consists of a mixture of hydrocarbon molecules containing between twenty and forty carbon atoms. It is solid at room temperature and begins to melt above approximately 37 °C (99 °F), and its boiling point is above 370 °C (698 °F). Common applications for paraffin wax include lubrication, electrical insulation, and candles; dyed paraffin wax can be made …

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What is the goop inside a lava lamp?

A classic lava lamp contains a standard incandescent or halogen lamp which heats a tall (often tapered) glass bottle. A formula from a 1968 US patent consisted of water and a transparent, translucent, or opaque mix of mineral oil, paraffin wax, and carbon tetrachloride. The clear water or mineral oil can optionally be coloured with translucent dyes.