6a Students know visible light is a small band within a very broad electromagnetic spectrum
PHYSICAL PRINCIPLES IN LIVING SYSTEMS Physical principles underlie biological structures and functions 7th grade CA Life Science Standards
Light
Hydrogen Absorption Energy 2 3 4 5 6563 Å photon
Hydrogen Emission Energy 2 3 4 5 6563 Å photon
Hydrogen Atom 434 nm 656 nm 486 nm 410 nm -e -e -e -e -e 400 nm 700 nm 2 656 nm -e 1 -e +P 486 nm 410 nm -e -e 400 nm 700 nm
Emission and Absorption Lines Lines come from electron transitions Energy change either comes from (absorption) or is given to (emission) photon. E Photon energy Frequency E = hf Frequency 1/(Wavelength) f = c/l Wavelength means COLOR
Hydrogen Spectrum 4 Brackett (Far IR) 3 Paschen (IR) Energy 2 Lyman (UV) 1 2 3 4 Balmer (VIS) Brackett (Far IR) Paschen (IR) Energy
Aluminum Argon Calcium Carbon Helium Hydrogen Iron Krypton Magnesium Neon Nitrogen Oxygen Sodium Sulfur Xenon
Demo: Spectral Emission Tubes
Demo: Flame Test
EM Spectrum
Uses of EM Radiation
ROYGBIV
Demo UV & Geology
Demo- Visualizing UV
6b Students know that for an object to be seen, light emitted by or scattered from it must be detected by the eye.
Retina - Photoreceptors
Optical Light Benches
6c Students know light travels in straight lines if the medium it travels through does not change.
6d Students know how simple lenses are used in a magnifying glass, the eye, a camera, a telescope, and a microscope.
Ray Diagram - Microscope
6e Students know that white light is a mixture of many wavelengths (colors) and that retinal cells react differently to different wavelengths.
Red/ Green/ Blue
Cyan / Yellow
6f Students know light can be reflected, refracted, transmitted, and absorbed by matter.
Reflection of visible light
Reflection – ray diagram
Demo – Reflection (Lasers)
Refraction
Demo: Refraction
Demo – Laser refraction
Demo – Refraction in Prism
Absorption of Light by Plants
Absorption Spectrum - Photosynthesis
6g Students know the angle of reflection of a light beam is equal to the angle of incidence.