light and sound test
Post on 27-Nov-2014
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Unit: Light and Sound Unit Test Study Guide Terms to Know: Light Beam – a group of many light rays
Light Ray – a thin line of light energy
Transparent – clearly see through
Translucent – allowing some light to pass through, but not enough to see clearly
Opaque – blocking all light from passing through it
Transmit – allow to pass through; a window will transmit light
Reflect – to bounce off an object
Absorb – to soak up something
Refract – to bend and change direction of light
Spectrum – a band of colours that occurs when light is refracted and split
Prism – a transparent piece of glass or plastic that can split light
You Should Know that: • Light beams are made of groups of many light rays which travel in a straight line • How shadows are made:
o Light beams are blocked by opaque objects. Since the light beam can not transmit or go through the object a shadow is made.
• We need reflected light to see. Almost every object we see, we see because light reflects off it.
o There must be a source of light o The light must hit an object o The light must be reflected from the object to your eye.
• Two different ways that we see objects: o Light beams hit an object and reflect to our eyes. o Light directly reaches our eyes.
• Refraction: o Refraction happens when light goes through a transparent or translucent solid or
liquid and slows down. Slowing light down causes the object to appear like it is bending.
o Birds need to look and dive straight down so that they can see where a fish or animal is exactly. If they look at it from an angle, the prey will appear to be in a different spot.
• Opaque materials do not transmit any light. All of the light that strikes an opaque material is reflected or absorbed.
o Light colours reflect more light and are cooler. o Shiny opaque materials reflect the most light. o Dark colours or materials with a rough surface absorb more light and are hotter.
• White light is made up of a spectrum of colours. • When white light is split, it makes the colours of the rainbow or Roy G. Biv.
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