100 likes | 227 Views
Light interactions. Review:. Light – EM waves produced by the vibration of particles Visible light – part of the EM spectrum that we see and that interacts with materials around us Transmission: any transfer of energy through matter or space
E N D
Review: • Light – EM waves produced by the vibration of particles • Visible light – part of the EM spectrum that we see and that interacts with materials around us • Transmission: any transfer of energy through matter or space • Light will transfer through a medium or empty space
Materials • Transparent • Light passes through the object completely • Examples: plastic wrap, windows • Translucent • Light passes through the object somewhat • Examples: frosted glass, wax paper • Opaque • Light does not pass through the object • Examples: books, aluminum foil
Reflection and Refraction • Processes where light is manipulated, changed
Reflection • Light hits and object and bounces back to the viewer • The light bounces back at the same angle it hit the object • Examples: mirrors, some windows • Smooth surfaces create regular reflections which means that the light reflects in one direction • Rough surfaces create diffuse reflections which mean that the light reflects in different direction. • Diagram:
Refraction • Light hits an object and travels through it BUT • It will travel through the object at a different angle than how it hit • Creates an optical illusion. Objects may be closer or further away from where you think they are. Ex. A fish in the water. • When white light is refracted, you can see the entire visible spectrum. • Examples: light traveling from air to water, prism • Diagram
Absorption • Light is taken in by an object • Example: • when a beam of light shines through the air, particles in the air absorb some of the energy from the light. AS a result, the beam of light becomes dim.
Scattering • Light is broken up and travels through a medium in smaller particles • Example: • Beam of light scatters because of air particles, allowing you to see things that are outside of the beam. • Scattering makes the sky blue-shorter wavelengths scatter the most
Diffraction • Bending of waves around barriers or through openings • Depends on it wavelength and the size of the barrier/opening • Wavelength of visible light is very small – so it cannot bend very much unless it passes through a narrow opening, sharp edge • Light waves cannot diffract around large obstacles (buildings). Thus, you can’t see around corners