Module 2 Light
• Lesson 1: How light travels
• Lesson 2: Reflection and Mirrors
• Lesson 3: Refraction and Lenses
• Lesson 4: Color of Light
Module 2 Light:
L1
How Light Travels
Learning Objectives
• Use models to describe light’s
path
• Describe how objects function to
interact with light waves
through, reflection, absorption
and transmission
Traveling Waves p.65
Sound and light waves both travel by waves. In order to
hear sound or see light, waves must travel from one place
to another and enter either your ears or eyes. How do
you think these waves travel? Circle the response that
best matches your thinking.
A. One needs to travel through matter
B. Neither needs to travel through matter
C. They both need to travel through matter
What is Light?
• Neither matter or energy
• Light carries energy and travels as a
wave.
• Light waves travel in straight lines.
• Light is a electromagnetic radiation
• Light travels at 300 000 000 m/s or
300 000 km/s (much faster than
sound).
p.7
Electromagnetic Spectrum
• HW: p. 71
Properties of Light
• nanometers(nm)
What is the difference between mechanical
waves and electromagnetic waves?
Waves and Energy
Mechanical Waves
• The more energy the wave has, the
greater the wave’s amplitude
Electromagnetic Waves
• The more energy the wave has, the
higher the wave’s frequency
Higher Frequency= Higher Energy
Speed of Light p.74
Questions
• What do you observe about the
speed of light?
• Light waves slows down when
they travel through matter.
• How many times faster is the
speed of light than the speed of
sound?
• 900,000 times faster
Compare Light and Sound Waves p.74
Compare at least 5 characteristics
Compare Light and Sound Waves -Ans
• Both light and sound are waves
• Sound waves require a medium
to travel through, and the
• They both have wavelengths and
denser the medium, the faster
frequences.
they travel.
• The energy of a sound waves is
• Light waves require no medium
related to its amplitude
and the denser the medium is,
• The energy of a light wave is
the slower they travel
related to frequency
Light Interactions of Matter
• Evidence needed for
Light(p.77)
• Transmission
• Absorption
• Reflection
Write down what you think the following words
mean:
Make this into a fill in the blank activity to
practice!
1.
2.
3.
4.
5.
6.
Transparent
Opaque
Translucent
Transmit
Reflect
Absorb
1.
Transparent: objects that transmit light and
you can see through them
2.
Opaque: objects that absorb, scatter, or
reflect light and do not allow any light to
pass through
3.
Translucent: Objects that transmit light but
diffusing(scattering) light as it passes
through
4.
Transmit: When light or other radiation
passes through an object
5.
Reflect: bounce off
6.
Absorb: taken into a material
Light Pollution
• https://www.nationalgeographic
.org/video/light-pollution-101/
(Taiwan) EPA to introduce
guidelines on light pollution at
night
• https://en.rti.org.tw/news/view
/id/2002102
• https://www.darksky.org/ourwork/conservation/idsp/parks/h
ehuanmountain/
Homework
• p.82-84