Access Prior Knowledge
Lesson 3: What is light energy?
Opening Activity
Open Science textbook to page 458.
Open Workbook to page 141A to check homework.
Open Science folder to review vocabulary words and outline for the chapter.
Open Science journal and answer the following questions:
1-Sound waves travel through materials at different speeds depending on the
density of the material. Rank in order, from slowest to fastest, the speed of
sound waves in water, air and steel?
Review Content Cards and Q-Cards in bin, sharing with partners quizzing each
other quietly.
Log in to clickers using student ID number.
Be ready to review home learning when timer goes off.
Don't forget to write your
home learning in your
agenda page 142A.
Do you agree with the statement?
Similar to sound waves, light waves carry
electrical and magnetic energy.
Do you agree with the statement?
Wavelength is measured from the top of one
wave to the top of another wave.
Do you agree with the statement?
We can see most of the light in the spectrum.
Do you agree with the statement?
When light enters new material, it will bend.
Electromagnetic Radiation
Light is like sound because it moves in waves.
-Light waves have wavelengths and frequencies and the speed of light
changes when it moves through different materials.
Light can be reflected or absorbed by certain objects or, light can pass
through them.
Light is a form of electromagnetic radiation, which means light energy is
made of electrical and magnetic energy.
The electromagnetic spectrum is a range of waves that have many
frequencies and wavelengths, including visible light that makes up a small
part of the electromagnetic spectrum.
-Different wavelengths of visible light are seen as different colors.
How does light move?
The speed of light changes when it moves through different materials.
Light can travel through a vacuum, where the speed of light is fastest.
Light travels more slowly through materials such as air or water.
Three things can happen when light hits an object, it can reflect, refract, or
be absorbed.
Reflection
Light moves in a straight line,
even when it reflects off an
object, such as a mirror, but
the light moves in a different
direction.
Refraction
Refraction is when light bends
when it enters a new material. A
lens is a clear object that bends
light.
How does light move?
Some materials absorb light and change light energy into thermal
energy, but some light frequencies are not absorbed.
They can pass through the material or are reflected off the material.
This creates the colors we see.
-For example, a red shirt absorbs many light frequencies, but it reflects red
light.
BRAIN POP: Light
MatchQuest
TextQuest
Answer in your Science Journal
1. What happens to light rays as it hits a convex lens?
2. Explain the difference between reflection and refraction.
3. Why are we able to see certain colors?
4. How is light energy similar to sound energy?
Don't forget to write your
home learning in your
agenda page 142A.