Sound waves will be ... by hard flat surfaces. Echoes are just ... sound waves. Sound waves will refract as they enter different media. -Denser material causes them to speed up
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Card 7
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... is sound with frequencies above 20,000 Hz. They get partially reflected at boundaries- some is transmitted, some is reflected. Time taken to reach a detector determines how far away the boundary is
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Card 8
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Ultrasound use: The waves pass through the body, when it meets a boundary, some is reflected back. Timing and distribution is processed by a computer. No-one knows how safe it is, but X-rays are too dangerous
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Card 9
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Ultrasound use: Find flaws in objects like pipes or wood and metal. Ultrasound waves are reflected from far side of material. If there is a flaw e.g. a crack, wave is reflected sooner
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Card 10
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... sounding uses high frequency sound waves. used by boats and submarines to find depth of water or find objects in deep water
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Card 11
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Waves have different ... depending on material they are travelling through. Meeting a boundary can result in: -Partial or total reflection -Refraction or absorption -Change of speed. Using different waves helps to study ... of materials we cant see
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Card 12
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When ... meet a boundary, some waves will be absorbed and some waves refracted. When waves are refracted they change speed gradually so take a curved path. A change of properties, speeds up the waves
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Card 13
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Seismic wave: Longitudinal, travel through solids and liquids and are faster than the other type of seismic wave
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Card 14
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Seismic Wave: Transverse wave, can't travel through liquids or gases, slower than the other type of seismic wave.
