230 likes | 341 Views
Chapters 10 & 11. Light and Color. Electromagnetic Spectrum. Electromagnetic Spectrum. As wavelength increases, frequency decreases Indirect relationship About 5%, not much It is called visible light. What is the relationship between wavelength and frequency?
E N D
Chapters 10 & 11 Light and Color
Electromagnetic Spectrum • As wavelength increases, frequency decreases • Indirect relationship • About 5%, not much • It is called visible light What is the relationship between wavelength and frequency? Approximately what percent of the EM spectrum can we see?
Examples of EM Radiation • Radio • TV broadcasting • AM and FM broadcast radio • Avalanche beacons • Heart rate monitors • Cell phones What are some common examples of non-visible EM energy?
Examples of EM Radiation • Microwaves • Microwave ovens • Bluetooth headsets • Wireless internet • Radar • GPS What are some common examples of non-visible EM energy?
Examples of EM Radiation • Infrared • Night vision goggles • Remote controls • Heat-seeking missiles • Heat lamp What are some common examples of non-visible EM energy?
Examples of EM Radiation • Ultraviolet • Black lights • Sterilizing medical equipment • Water disinfection • Security images on money • Tanning beds What are some common examples of non-visible EM energy?
Examples of EM Radiation • X-rays • Medical imaging • Airport security • Inspecting industrial welds What are some common examples of non-visible EM energy?
Examples of EM Radiation • Gamma • Food irradiation • Cancer treatment • Soil density • Treating wood flooring What are some common examples of non-visible EM energy?
Electromagnetic Spectrum Percent of each type that reaches the surface.
Transparent vs. Opaque • What is the difference between transparent and opaque? • Transparent objects allow light to pass straight through them • Ex. Glass and water • Opaque objects absorb light, so no light passes through • Ex. People and books
Color • Why do objects appear to be certain colors? • Based on the frequency of light we see with our eyes • We normally only see the colors that an object is reflecting
Primary Colors • What are the primary colors? • Red, green and blue • When these three colors of light are combined they created white light
Secondary Colors • How are the secondary colors created? • Color addition - cyan, yellow and magenta which are created by adding two or more primary colors • Complementary colors - two colors that added together make white
Color Addition and Subtraction • How is color subtraction different from addition? • With subtraction, you put a filter between your eyes and the light • A filter absorbs (subtracts) certain colors and allows others to pass through
Dyes and Pigments • What are dyes and pigments? • Particles that absorb certain colors • Mixing pigments does not get the same result as mixing light
Mixing Pigments • What colors make up a picture in a textbook? • Subtractive primaries, which are magenta, cyan and yellow • These colors absorb some light and reflects others which gives a picture its color
Why is the sky blue? The sky is blue because oxygen and nitrogen particles absorb light and reemit (release) it as blue and violet. Our eyes are not sensitive enough to see violet though.
Why are sunsets red? There is more atmosphere through which the sunlight travels. This allows for more scattering of the other colors and red to be transmitted.
Why are clouds white? Different sized groups of water droplets scatter different wavelengths of light which makes clouds bright and white.