chemicals. for example rain is slightly acidic and causes the minerals in the rock to react with the rain. this causes weathering.
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what is physical weathering caused by?
physical processes such as changes in temperature, freezing and thawing as well as the effects of wind, rain and waves.
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what is freeze-thaw?
when water freezes it expands. freeze-thaw is when water gets into a crack of a rock and expands by getting cold. as it expands, the crack gets bigger and eventually pieces of rock fall off.
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what is erosion?
the movement of the broken pieces away from the site of weathering.
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how does light travel?
by waves
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what is a incident ray?
the light going towards something
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what is a reflected ray?
the light coming away from the mirror
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what is the angle of incidence?
the angle between the normal and incidence ray
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what is the angle of reflection?
the angle between the normal and reflected ray
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what is refraction?
when light waves change speed as they pass across the boundry between two substances with different densitys
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what is dispersion?
where light is refracted and each colour is refracted by a different amount. this means that the light leaving the object is spread out into its different colours.
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what are the seven colours of the light spectrum?
red, orange, yellow, green, blue, indigo, violet
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what are the three primary colours?
red, green, blue
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what are the three secondary colours?
cyan, yellow, magenta
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what colour do the three main primary colours create?
white
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how is coloured light mixed?
the light hits a surface, some of it is absorbed and some is reflected. the light that is reflected is the colour of the object in that light.
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why do some objects appear black in white light?
because all the light is absorbed but none is reflected.
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