Chapter 9: What is Light? (3rd grade science)
When lasers were first invented, people called them:
"a solution looking for a problem"; meaning that scientists did not know what to use them for
How is the sun DIFFERENT from a light bulb?
1) does NOT require electricity, 2) it's natural light
What 3 things do you need to make a shadow?
1) light source 2) object 3) a place the light can't reach
What is refraction? What happens to light as it passes from air to water?
Bending light. It bends.
You are outside in the sun in white clothes. You feel comfortable. Your friend is wearing black. He is complaining about being hot. What is happening?
Bright/light colors reflect the light (and heat) while dark colors absorb the light (and heat)
Which absorbs more light - a dark blue object or light blue object? Explain.
Dark blue - dark colors absorb more light; lighter colors reflect more light
What happens to white light when it passes through a prism? What do you see?
Each color bends differently. It creates a rainbow.
What is light?
Form energy you can see
Infer: How does reflected light allow you to read?
Light reflects from the page to your eyes
How do you think people are making beaches too bright for turtles to lay their eggs on?
Lighted houses on the beach
Could you see a clear, sharp reflection in a piece of crumpled shiny wrapping paper?
No. It would be bumpy.
What creates a rainbow?
Rainbows are created by both reflection (bouncing) and refraction (bending) of light in water droplets in the atmosphere, which results in a spectrum of light appearing.
How is refraction DIFFERENT from reflection?
Reflection: BOUNCING light Refraction: BENDING light
How can you make a shadow disappear?
Shine a light on the shadow and it will become more faint.
It's a sunny day and you stand on the sidewalk at noon. You then stand in the same place in the early evening. Your shadow is different each time. Why?
The sun is in different places each time, changing your shadow.
Light bulb characteristics:
artificial light, requires electricity, creates light, and gives off heat
Why is the boy's hand on page 308 casting a shadow on the wall? What happened to the light that hit the boy's hand?
because the light couldn't reach it
refraction
bending of light
Describe shadow:
blocked light
reflection
bouncing light
What is reflection?
bouncing light (travels to in a straight line and then bounces off in a straight line)
How do people use lasers to communicate?
cell phones, phones
Uses for lasers in everyday life:
cell phones, phones, entertainment, ipods, ipads
What sources of light could cause light pollution?
city lights, parking lot lights, baseball field lights
conclude
come up with an answer
How is the sun LIKE a light bulb?
creates light and gives heat
light
energy you can see
What is light pollution?
excessive, misdirected, or obtrusive artificial light that makes it so we can't see the stars
measure
how much? or how many?
What happens to light when it hits a smooth, shiny surface?
it reflects
What properties of laser light make lasers useful to people?
it's controllable and you can direct it to one spot
How are laser light and sunlight different?
laser light is controllable / sunlight is NOT controllable
In some places, why is it hard to see the stars at night?
light pollution
Why is the sun important?
living things around the world need energy from the sun
What is a laser?
man-made light
Sun characteristics:
natural light, doesn't require electricity; creates light, and gives off heat
Name the sources of light written in the text and pictures on pages 298-299.
sun, fire, lamp, and light bulb
What is absorption?
taking in of light
absorption
taking in of light
How are laser light and sunlight alike?
they both give off light
How can you reduce light pollution?
turn off lights
