Light travels in ____ lines from a source Light travels as ____ waves It travels much ____ than sound Light does ____ need a substance to travel through. Light travels through ____ objects but not through ____ objects Shadows are made when light is ____ by an object. Opaque objects block ____ light. ____ objects allow some light to pass through, but it is scattered so you do not see a ____ image. Transparent materials let light pass ____ through Light rays are scattered by ____ surfaces (____ reflection), which means that you cannot see an ____ in an object with a rough surface. Mirrors and ____ materials such as polished metals ____ light evenly. This is called ____ reflection. The angle of incidence (i) is ____ to the angle of ____ (r) – this is known as the ____ of reflection. Angles are measured between the light rays and the ____ (a line drawn at ____ angles to the ____ surface). When light hits something ____ it changes ____ and ____. This is called ____. Refraction takes place at the ____ between two ____. When light is transmitted through glass it ____ down and changes direction ____ the normal. When it travels back out it speeds ____ again and changes direction ____ from the normal. A ____ is made only of ____ and hydrogen. Many fuels are mainly hydrocarbons ____ is also an ____ reaction because the substances react with ____Carbon and hydrogen are ____ but metals can also be oxidised: metal + oxygen = ____ Conservation of mass in reactionsIn a ____, the mass of the ____ is always the ____ as the mass of the ____ Metals can appear to ____ mass when ____ in air: zinc + oxygen  ____ The difference in mass is the mass of ____ that reacted. When a hydrocarbon fuel ____, it appears to lose mass because the products of the reaction (carbon ____, ____) are lost into the air. The fire triangle and putting fires ____The fire triangle shows the ____ factors needed for a fire to ____. If any factor is ____, the ____ will go out. We use fire ____ to put out fires. Water extinguishers remove ____. Powder and ____ extinguishers exclude ____. Foam extinguishers can both remove heat and exclude oxygen.

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