Electrons and Light So what exactly is light

Electrons and Light!

So what exactly is light? p Light is a wave of energy, a small part of the entire electromagnetic spectrum!

How Do Humans See Color

Light as a Wave p p Light moves in waves from the light source to your eye or other detectors! Waves have several characteristics!

Wave Characteristics c = λ× ν c = speed of light = 3. 00 × 108 m/s λ = wavelength ν = frequency

Light can also act as particles, we call them PHOTONS!!!!!! p Moving along those waves, there are little packets of energy called photons. n Photons have specific amounts of energy as determined by the frequency of the light. n. E n n =h×ν The higher the frequency of the light, the more energy the light has. h = 6. 626 × 10 -34 Js

Atomic Emission Spectrum p Atomic emission spectra are unique spectra of light emitted by an element when electricity is run through it or when it is viewed through a prism. p Elements can be identified by the colors of light they give off when heated or electricity is run through them.

Atomic Emission Spectrum

Sodium

So what is this used for? p To determine the age of a star n n n Stars fuse elements together in a process called nuclear fusion. A lot of light and energy is created. Stars are different colors depending on what element is present in the highest amounts. The higher the atomic number of the element, the heavier the element is and the older the star is. Star temperatures are dependent on the color as well.

Class O stars are the hottest and youngest p Class M stars are the coolest and oldest p

Firework colors