Download light waves

Light
How do we see?
Light Wave
What is Light?
• Light is a form of energy that has the ability to
cause change, such as heating an object.
• A combination of several different
wavelengths of light traveling together is
called white light.
• The visible spectrum is the band of light
waves of different colors in the
electromagnetic spectrum that vibrates at
different frequencies our eyes can detect.
How does light travel?
• Just like sound, light travels in waves and
some light is not detected by our eyes.
• A photon is a small particle of light that travels
in a straight pathway.
• The color of light is determined by its
wavelength.
• The color red has the longest wavelength.
• The color violet has the shortest wavelength.
• ROY G. BIV
Diffusion
How does it travel?
• Diffraction or Diffusion is breaking white light
into its 7 component colors, the visible
spectrum.
• Frequency is the amount of crests to pass a
given point in space in one second. It is
measured in Hertz.
• Peak is the highest point of the wave.
• Transmit means to allow light to pass through.
How does Light Travel?
• Light doesn’t need a medium or material to
travel through.
• Light from the sun can travel 150 million km
or 90 million miles to Earth in less than 8 ½
minutes.
• Light and sound have many ways they are
similar and different.
• Can you give any examples?
Refraction
Reflection Vs. Refraction
• Reflection is the change in the direction of
waves after they bounce off a surface.
• Refraction is the bending of light waves as
they travel at an angle from one medium to
another.
• When light waves absorb, they take in as heat.
• When you see color, all colors all are absorbed
except the color you see.
Materials and Light
• Transparent materials let most light waves
pass through.
• Ex. glass and transparency film
• Opaque materials let no light waves through.
• Ex. wood
• Translucent materials let some light waves
pass through.
• Ex. frosted window glass
Prisms
Light Tools
• An optical tool that can be used to refract
white light to see the visible spectrum is called
a prism.
• A mirror is an optical tool that reflects images.
• A telescope is a optical tool that magnifies
distant objects or makes them appear larger.
Galileo made the 1st one in 1609.
• A microscope is an optical tool that magnifies
images using light.
Light
Concave Lens
Convex Lens
Lens
• Lens is usually made from transparent glass or
plastic. A light passes through a lens and it
undergoes 2 refractions.
• Concave lenses will diverge or spread out
light rays. It is thinnest at the center. Negative
lens
• Convex lenses will converge or focus light to
form an image. It is thickest at the center.
Positive lens