Light and Sound Energy/Earth’s Movements Summative Study Sheet
Test: Thursday, February 9th
LIGHT
Transmit- light rays passing straight through an object
Light ray- light traveling in a straight line
Reflection- light rays bounce off a surface
Convex lens- lens that is thicker in the middle than on the edges
Opaque- doesn’t allow light to travel through
Transparent- allows light to travel through
Translucent- allows some light to travel through
 Light always travels in a straight line unless something causes it to change direction. (ex: lens, prism, mirror)
 Light can be transmitted, refracted, reflected or absorbed depending on the material it strikes.
Reflection
 When light strikes a mirror or a surface that is a shiny material it bounces off.
 Objects that reflect light include: mirrors, sunglasses, shiny metals, tinted windows
Refraction
 When light strikes a lens it bends.
 When light is refracted objects look different than they normally would. They may look larger or even appear
bent.
Ray 1 is refracted
and Ray 2 is
reflected.


A prism bends or refracts light as it enters which separates the white light into the colors of the rainbow.
Objects that refract light include hand lens, eye glasses, cameras, telescopes, prisms and microscopes.
Sound Energy
* Sound energy is formed by vibrations.
* Vibrations are a series of quick back and forth motions.
* Sound vibrations form waves. Sound moves by waves.
* Sound waves can move through any form of matter. (medium)
* Sound waves move through matter by making the molecules (particles) bump against each other
and making the molecules (particles)vibrate.
* Sound waves move fast through solids because the particles are close together.
* Sound waves move a little slower in liquids because the particles are not as close together.
* Sound waves move very slow in gases because the particles are so far apart.
* Without atoms, sound waves cannot move or vibrate.
* Sound cannot travel in space because there is no medium for it to travel through.
Earth’s Movements
Rotation: Earth makes one complete rotation every 24 hours. The rotation of the Earth causes day and night. Because
of the rotation or Earth on its axis the sun appears to move across the sky. It rises in the east and sets in the west.
Revolution: It takes the earth 1 year or 365 days to make one revolution around the sun. The revolution of the earth
around the sun and the tilt of the earth on its axis causes the seasons.