Science--Chapter 4B

Chapter 4B Light and Sound


1. What is light?

     The visible spectrum is light energy that can be seen. The sun, fire electric lights, candles, matches, and flashlights are all sources of light.

     Light waves move in a straight line away from their source and can move through empty space.


2. When happens when light hits an object?

     Light can be reflected, absorbed, or transmitted when it hits different materials, and the color of light that is reflected or transmitted gives objects their color.

     Flat mirrors reflect good images, while curved mirrors reflect somewhat change images.

     Lenses cause light rays to bend by changing their speed and direction.


3. How does sound travel?

     Sound is made when matter is caused to vibrate.

     Volume and pitch are properties of sound.

     Sound waves travel through different materials at different speeds; they cannot travel through empty space.


4. How do you hear sound?

     You hear sounds when sound waves cause vibrations to move through your eat to a nerve and the nerve then sends messages to the brain.

     Stethoscopes, microphones, bullhorns, and hearing aids can be used to make sounds louder.



Visible spectrum    light energy that can be seen and can be broken into the colors of the rainbow

Wavelength     the distance from a point on a wave to the same point on the next wave

Transparent    allows light to pass through so that whatever is behind can be seen

Translucent    allow slight to pass through but scatters it so that whatever is behind it cannot be clearly seen

Opaque    does not allow light to pass through

Transmit    to allow to pass through

Absorb     to take in

Reflect     to bounce back

Convex lens    a lens that is thicker in the middle than at the edges

Concave lens    a lens that is thinner in the middle than at the edges

Vibrate    to move quickly back and forth

Volume     the loudness or softness of a sound

Pitch     the highness or lowness of a sound

Stethoscope    an instrument used to hear the sounds of body organs

Microphone    an instrument used to amplify voices, music, and other sounds

Electric signal    a form of energy

Amplify    to make stronger

Bullhorn     an instrument with a built-in microphone that makes sound louder

Hearing aid     an instrument used to help people with a hearing problem hear better