Magenta Ain't A Colour. A beam of white light is made up of all the colours in the spectrum. The range extends from red through to violet, with orange, yellow, green and blue in between. But there is one colour that is notable by its absence. You should have seen a green afterimage, but why is this significant? The afterimage always shows the colour that is complementary to the colour of the image. It is a common misconception that red is complementary to green.
All the colours in the light spectrum have complements that exist within the spectrum – except green. The light spectrum consists of a range of wavelengths of electromagnetic radiation. When our eyes see colours, they are actually detecting the different wavelengths of the light hitting the retina. If the eye receives light of more than one wavelength, the colour generated in the brain is formed from the sum of the input responses on the retina.
You can find out more about Liz on her Nullpage. -Biotele A note from Biotele: Online Scientific Calculator. Download eCalc Scientific Calculator Windows VersionMac OSX VersionView More Downloads Online Calculator and Math Help eCalc is a free and easy to use scientific calculator that supports many advanced features including unit conversion, equation solving, and even complex-number math. eCalc is offered as both a free online calculator and as a downloadable calculator. Input Mode (Algebraic vs. RPN) The online calculator operates in either algebraic input (default mode) or RPN input. Algebraic Mode Algebraic input mode is commonly referred to as "infix notation" and is widely used by most handheld calculators. Graphical Button and Keyboard Support The online calculator supports data entry through either a graphical button or through the use of traditional computer keyboard keys.
Stack The stack is a feature of the calculator that provides a way to view a history of results. Pallet Intro Basic Functions Addition Subtraction Multiplication Division Sign Square Square Root Raise to the Power Logarithm Sine. Frequent Halos. Halos appear in our skies far more often than do rainbows. They can be seen on average twice a week in Europe and parts of the United States. The 22° radius circular halo and sundogs (parhelia) are the most frequent. In this HaloSim3 simulation the sun is surrounded by a 22° halo and flanked by sundogs. Passing through the sundogs and extending beyond them is the parhelic circle. Click the simulation text to go to the halo. Rock Key. The Rock Identification Key - by Don PeckRock Key Table of Contents What Are Rocks? Rocks are what the crust of the earth is made of. They are the mountains and the bottom of the ocean. They are everywhere on earth, but often buried under soil.
Rocks are made of minerals, like quartz, calcite, feldspars, and micas. Most rocks are made from more than one mineral, but there are quite a few kinds that are made from only one mineral. . [ Return to Rock Key Table of Contents ] What Minerals Form Rocks? Planetarium - Interactive star map and virtual sky. List of Meteor Showers.