Sound Energy & Light Energy Test Review

Time for Learning!! Sound and Light

Sound Energy Fact: Sound is one of the fastest types of energy in the universe, at about 340 yards per second. Light is even faster than sound!

How is Sound made? Energy is applied. Molecules in an object start vibrating. Sound waves travel out in all directions. The sound waves hit the human ear, allowing us to hear the sound. Example: A worker slams his fist down on the table. The energy from the worker’s fist is applied to the table. The molecules in the table begin vibrating. Then, sound waves travel out in all directions. The sound waves hit the ears of the worker’s assistant, allowing her to hear.

How Does Sound Travel? Sound waves travel in all directions. Example: Three teachers in different parts of the building all hear two students talking. This is because sound waves travel in all directions.

What Happens to Sound While it is Traveling? Slide 1 When sound hits a hard surface, there is a chance it could reflect off, creating an echo. Sound reflects best off smooth, hard, non porous materials. Example: A mother yells at her child for misbehaving. Her shout hits the wall, and bounces back. The child hears the shout and its echo.

What Happens to Sound When it is Traveling? Slide 2 Sound cannot travel in empty space, since there is nothing to vibrate. Example: A supernova explosion happens in space. Yet nothing is heard.

What Happens to Sound when it is Traveling? Slide 3 Sound can travel through solids, liquids, and gases. Sound travels best through solids. An example of a solid is a brick. An example of a liquid is juice. An example of a gas is air.

Reflection and Absorption of Sound Sound can be reflected. When Sound hits a hard surface, it might be reflected off it. Sound can be absorbed. When sound hits a soft surface, it might be absorbed into it.

Light Energy Fact: Light is the fastest type of energy in the universe, at about 186,000 miles per second.

How is Light Made? Heat must be created. The heat must glow. The light waves created from the glow have rays in them, which travel in straight lines. The light rays hit the human eye, allowing us to see the light. Example: Electricity heats a lightbulb. The lightbulb glows. Light waves are sent out, with tons of rays in them. The rays reach our eye, allowing us to see the light.

How Does Light Travel? Light travels in straight lines. Light waves are made of tons of light rays. Each light ray follows a certain straight path.

What Happens to Light When it is Traveling? Slide 1 When light hits a mirror, it reflects off it, creating a mirror image. Example: When you point a laser at a mirror, it reflects (bounces) off. Fact: When you point a light at a mirror, the angle it went in will always be the angle it came out. This is the law of reflection.

What Happens to Light When it is Traveling? Slide 2 Light can travel in empty space. Example: We get light from the sun. The light from the sun travels through empty space until it reaches the earth’s atmosphere.

What Happens to Light When it is Traveling? Slide 3 Light can travel through solids, liquids, and gases. Light can travel through any transparent and translucent items. Light does not travel through opaque items. Opaque items cast a shadow. An example of a solid is a glass pane. An example of a liquid is water. An example of a gas is carbon dioxide.

Reflection and Absorption of Light Light can be reflected. When light hits a white surface, all colors are reflected back to the eye. Light can be absorbed. When light hits a black surface, all colors are absorbed, and nothing is reflected back to the eye.

Refraction of Light Refraction is how light bends when moving from one substance to a denser or less dense substance. Example: There is a pencil in a cup of water. When light moves from air to water, it bends, making the pencil look broken.

Time for Questions!! Q & A Sound and Light

Which travels slower: sound or light? Question 1 Which travels slower: sound or light?

Answer to Question 1 Sound travels slower.

Light travels in straight lines. How does sound travel? Question 2 Light travels in straight lines. How does sound travel?

Sound travels in all directions. Answer to Question 2 Sound travels in all directions.

Time for Questions!! True or False Sound and Light

True or false: Heat needs to glow for sound waves to be created. Question 3 True or false: Heat needs to glow for sound waves to be created.

False; an object needs to vibrate for sound waves to be created. Answer to Question 3 False; an object needs to vibrate for sound waves to be created.

True or false: Absorption is a property of sound alone. Question 4 True or false: Absorption is a property of sound alone.

False; absorption is a property of both sound and light. Answer to Question 4 False; absorption is a property of both sound and light.

Time for Questions!! Multiple Choice Sound and Light

Question 5 Name a property that only light has. A: Reflection B: Refraction C: Absorption

Answer to Question 5 B: Refraction

Question 6 What happens to light when it hits a mirror? A: Nothing B: It reflects C: It is absorbed

Answer to Question 6 B: It reflects

Thank you for Going Through This Test Review What do you think you learned?