Convection Dispersion
Learning Objectives You should learn : How a light ray is deviated by a prism, How white light is dispersed by a prism, The colours of a white light spectrum, About the wavelengths of different colours.
Here is a glass prism: A ray of white light arrives
away from or towards the normal the normal What happens to the ray of light? It is (mainly) reflected or refracted ? away from or towards the normal the normal But different colours are refracted by different angles.
devi ated In fact, the ray is : (bent through an angle), and dispersed (split up into separate colours) like this.
Red is deviated most / least ? least screen What happens now? Red is deviated most / least ? least Violet is deviated most / least ? most
There is a spectrum on the screen: V screen There is a spectrum on the screen: Red Orange Yellow Green Blue Indigo Violet ROY G BIV
What is the real difference between red and violet light ? 4 10 000 mm wavelength violet red 7 10 000 mm
Learning Outcomes You should now: Understand what happens when white light enters a prism, Distinguish between deviation and dispersion, Know the colours of the spectrum, in order, Understand the connection between colour and wavelength.
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Definition of Dispersion Dispersion is the separation of white light into a spectrum by the process of refraction.
Dispersion with a prism Violet is deviated the most Red is deviated the least Prism showing light dispersion for different colours - Explore Science Prism & Dispersion - Great Barr School Dispersion - Crocodile Clip Presentation web site: www.ktaggart.com
The spectrum of white light The numbers are the wavelengths of the colours in nanometres where 1 nanometre = 0.000 000 001m. Sequential Puzzle on Colour Spectrum order- by KT web site: www.ktaggart.com
The cause of dispersion Dispersion occurs because different colours of light travel at slightly different speeds through transparent substances. In glass, perspex and water red travels quickest, violet slowest.
An example of dispersion caused by water Convection The rainbow An example of dispersion caused by water
Question 1 Choose appropriate words to fill the gaps in the paragraph below: ____________ occurs when white light is split up into a ____________ by the process of refraction. In glass violet light travels more __________ than the other colours and so is deviated the _________. The spectrum consists of red, ________, __________, _________, ________, indigo and _________. A __________ is formed when water causes dispersion.
Question 2 Explain why orange light is deviated less than blue light in a prism, we know that indigo light travels slower than green light through water, there are seven colours in the spectrum list.
Simulations Prism showing light dispersion for different colours - Explore Science Prism & Dispersion - Great Barr School Dispersion - Crocodile Clip Presentation Sequential Puzzle on Colour Spectrum order- by KT - Microsoft WORD version Prism - multishape prism and single light ray - no extra reflections - netfirms Prism - non dispersive reflections and refractions - NTNU
Convection Crossword – by KT Puzzles Convection Crossword – by KT
Related Presentaions Refraction Powerpoint by KT Colour Powerpoint by KT