BUT FIRST, A QUIZ!!!!!! The Plan… 10 April 2013 Review Homework (CYU P 143) Section 4.2 “Properties of Visible Light” Your friend, and my friend Bill Nye Reading Checks P. 146 & P. 149 Get your Title Page out… Work on your Vocab Why? Unit Test next Thursday… BUT FIRST, A QUIZ!!!!!! (c) McGraw Hill Ryerson 2007

4.2 Properties of Visible Light The wave model of light describes light as a wave that travels through empty space. Light energy is transferred from one location to another, such as from the Sun to the Earth. Visible light is light energy you can see. Refraction is the bending of wave due to a change in its speed. Light waves refract when they pass from one material to another. See pages 144 - 145 (c) McGraw Hill Ryerson 2007

Refraction of Light 101 White light, such as sunlight, is made up of waves having different wavelengths and frequencies. If a light wave is refracted, such as by passing through a prism (see Figure 4.10), the different wavelengths bend by different amounts. Because the longer wavelengths are refracted less than the shorter wavelengths, different colours are separated when they emerge from the prism. (c) McGraw Hill Ryerson 2007

Colours of the Rainbow R O Y G B I V White light is made up of waves of different wavelengths. Different wavelengths refract light by different amounts. When white light is separated into its different colours, this band of colour is called the spectrum. The seven most visible colours of the spectrum are: Red, Orange, Yellow, Green, Blue, Indigo, Violet. (ROY G BIV) R O Y G B I V See page 146 (c) McGraw Hill Ryerson 2007

Producing the Visible Spectrum A prism causes white light to split into a spectrum. Depending on the wavelength of the refracted white light, the visible colour will be different… White light, such as sunlight, is the result of mixing together all the different colours of light. See page 147 (c) McGraw Hill Ryerson 2007

The Visible Spectrum & Wavelengths (c) McGraw Hill Ryerson 2007

Reflection occurs when light bounces off an object. Colour and Reflection Reflection occurs when light bounces off an object. When white light strikes an object, some colours are reflected and some are absorbed. Only the reflected colours can be seen. For example, yellow cloth reflects yellow and absorbs all other colours. The three additive primary colours of light are: red, green, and blue. See page 148 (c) McGraw Hill Ryerson 2007

BILL! BILL! BILL! BILL! When finished: RC P. 146 & 149 http://www.youtube.com/watch?v=gtgBHsSzCPE When finished: RC P. 146 & 149 Complete 4.2 handout (c) McGraw Hill Ryerson 2007