Light is an electromagnetic wave that travels in straight lines and does not require a medium. It reflects at the same angle it strikes a surface, such as a mirror. Refraction occurs when light passes from one medium to another, such as from air to water, causing the light to bend. The primary colors of light are red, green, and blue, and when combined produce white light. Light travels at 300,000 km/s and has properties of waves like crests, troughs and wavelength. The visible light spectrum ranges from long wavelength red light to short wavelength violet light.

2. Characteristic of Light
•Light is an
electromagnetic wave.
•Light travels in a
straight line.
•Light is a transverse
wave, and does not
need any medium to
travel.

3. • electromagnetic waves
(of which visible light is
oneexample) are
transmitted as a signal
that our radios pick up
so we can listen to
music. Pulses of
infrared light are
transmitted as signals
so we can
communicate with our
TVs. This
backgrounder is all
about visible lightand
how we interact with it.

4. Properties of Light
• when light passes from one material into
a second material like mirror or water,
the light path is reflected back.
•Reflection- light bounces back into the
direction of the source.
•objects that reflect light- Water, windows,
shiny metal, and mirrors are some example.
• Light bounce= ball bounces back on hard
smooth surface

5. •When you throw a ball at
an angle, it will bounce off
at the same angle away
from you.
•Light reflects the same way
off a mirror. Light bounces
off at the same angle that it
struck the mirror.

6. Application
•Reflections in
rear-view mirrors
of cars help to
keep us safe.

7. Properties of Light
• when light passes from one material into a
second material like mirror or water, the
light path is bent .
• Refraction- bending of light as it travels
from one type of material to another like
from air to water.

8. Application
•Refraction
through lenses
of eyeglasses or
contact lens’
helps some
people see
better.

9. Primary Colors of Light
art class
primary colors are red, yellow and blue.
secondary colors orange, green and purple.
Light
primary colors: red, green, and blue
secondary colors:
cyan (made by combining blue and green),
magenta (made by combining blue and red)
yellow (made by combining green and red).
*When the primary colors of light are combined,
they make white light.

10. Colors of Light
•White light- has different
colors which is the color of the
rainbow.
- all colors that we see around
us are colors that come from
the light of the sun.

11. Colors of Light
•Rainbow- formed when the light
from the sun passes through
raindrops.
•A rainbow is the result of sunlight
breaking into different colors. As the
light from the sun bends, it
separates into different colors or the
colors of the rainbow, which is red,
orange, yellow, green, blue, indigo
and violet or the ROYGBIV.

12. Speed of Light
• movement of light
- travels at approximately 299 792 458 metres
per second (m/s) in a vacuum (a container
with no air). – 300,000,000 m/s
- An important thing to know about light is that
it travels in a straight line through a material.
- Speed of sound- approximately 300 m/s.

13. Waves and the Spectrum of Light
• Light has the properties of waves. Like
ocean waves.
•Parts of Light waves:

14. Parts of Light waves:
•1. crests- upper fold of the wave
•2. troughs- lower portion of the wave
•3. wavelength - The distance between one crest
and the next, which is the same as the distance
between one trough and the next.
•4. frequency of a wave- is the number of crests (or
troughs) that pass a point in one second. The
wavelength multiplied by the frequency equals the
speed at which the wave travels.
•

15. Electromagnetic waves (which visible light)

16. •Red light has the longest wavelength, and the lowest
frequency of the visible spectrum.
•Violet has the shortest wavelength, and the highest
frequency of the visible spectrum.

17. Light not visible to humans
Ultraviolet light and x-rays are also light, but have too
small wavelength and too high frequency to be visible to
us.
Infrared light which can be detected by
night-vision goggles, and
radio waves, which are picked up by your radio so you
can hear music, have wavelengths which are too long
and frequencies which are too low to be seen by the
human eye.