1. LIGHT

2. Standards
S8PS4. Students will explore the wave nature of sound and electromagnetic radiation.
B. describe how the behavior of light waves is manipulated causing reflection, refraction, diffraction, and absorption.
D. describe how the behavior of waves of affected by a medium ( such as air, water, solids).

3. LIGHT WAVES: TYPE OF ELECTROMAGNETIC WAVE CAN TRAVEL THROUGH SPACE
CAN ALSO TRAVEL THROUGH A MEDIUM
SPEED OF LIGHT = 300,000 KM/S
Light waves can behave in various ways:
reflection
refraction
diffraction
interference
transmission (“transmit”)
absorption (“absorb”)

4. How Materials Transmit Light
TRANSPARENT: material that allows most light to pass through, objects can be seen through transparent material
EX. Air, water, clear glass
TRANSLUCENT: materials that transmits some light, but objects cannot be seen clearly
EX. Lampshades, frosted windows, curtains
OPAQUE: material that does not allow any light to pass through
EX. Wood, rock, metal

5. Identify each as either transparent, translucent, or opaque:

6. LIGHT WAVE INTERACTIONS:
A. REFLECTION: waves “bounce off” a barrier
EX. Echo (sound waves), looking in a mirror

7. B. REFRACTION:
Bending of a wave when it enters a medium

8. C. DIFFRACTION:
the spreading out of waves due to an obstacle

9. D. INTERFERENCE:
The meeting and combining of waves
Wave Interference

10. E. ABSORPTION: F. TRANSMISSION
the disappearance of an EM wave into a medium (“absorb”)
Opposite of reflection & transmission
the passage of an EM wave through a medium (“transmit”)

11. WHY DO WE SEE COLOR? 1. FIRST, VISIBLE LIGHT MUST BE PRESENT!
2. ON THE EM SPECTRUM, VISIBLE LIGHT IS MADE UP OF
7 DIFFERENT WAVELENGTHS:
RED (longest wavelength, lowest frequency)
ORANGE
YELLOW
GREEN
BLUE
INDIGO
VIOLET (smallest wavelength, highest frequency)
Memory technique: ROY G BIV

12. When ALL 7 wavelengths combine, we see WHITE light.
Ex. Sunlight, light bulb
PRISM: tool that splits white light into 7 colors by using refraction
When an object ABSORBS all 7 colors, we see BLACK.

13. WHAT DETERMINES COLOR? TWO factors determine the color of an object:
reflection or absorption
wavelength of light
An object’s color is determined by the color that is REFLECTED.
Ex. This apple appears red because when light strikes red is reflected while the other 6 colors are absorbed.

14. Primary Colors of LIGHT
The human eye only detects 3 primary colors:
RED
GREEN
BLUE
Your brain detects mixtures of these primary colors so that you can see all colors/shades.
When the primary colors are all combined we see WHITE.