Friday, 23 September 2011

Science - Light

Light is an interesting topic.

Some of the topics we looked at:

  • primary colours and how they are different to the artist primary colours.  Colour mixing is also different.  
  • how objects actually reflect the colour the we see and absorb the rest of the colours.  
  • the difference between reflection and refraction and how light bends towards the normal (90 degrees) when it enters a denser medium and away from the normal when it enters a less dense medium.  
  • a prism and how it splits white light into the rainbow colours
  • travels in a straight line - not around corners
  • shadows
  • speed of light (extremely fast)

Periscopes use reflection to bend the light 2 x to allow the viewer to see things above the and around corners.  Periscopes are used in submarines, to look over walls, in tanks and to look around corners.  They were also used in the war in trenches to see what was happening on enemy lines and no man's land.


In other words....."Periscope comes from two Greek words, peri, meaning "around," and scopus, "to look." A periscope lets you look around walls, corners, or other obstacles. Sub-marines have periscopes so the sailors inside can see what's on the surface of the water, even if the ship itself is below the waves."  http://www.exploratorium.edu/science_explorer/periscope.html

Its seems like having a periscope is also a good idea for a spy-kid  http://www.topspysecrets.com/how-to-build-a-periscope.html

This one shows you how to make a periscope using a unwanted CD for mirror pieces  http://www.sciencetoymaker.org/periscope/asmblCD.htm



Here is a site that looks at periscopes and how to make one:



Have a look at this link on how to make 3 different kinds of periscopes http://www.youtube.com/watch?v=a0RTeYNsCxQ

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