60 likes | 188 Views
CHAPTER 17 SCIENCE. SOUND AND LIGHT ENERGY. LESSON 1. Sound energy is caused by vibrations in matter, this vibration produces waves in the matter, this wave movement is called a compression wave Sound is omnidirectional Sound has two major properties; volume and frequency
E N D
CHAPTER 17 SCIENCE SOUND AND LIGHT ENERGY
LESSON 1 • Sound energy is caused by vibrations in matter, this vibration produces waves in the matter, this wave movement is called a compression wave • Sound is omnidirectional • Sound has two major properties; volume and frequency • Volume is the loudness of sound ; it is measured in decibels • Decibels are calibrated in powers of ten, a 20 decibel sound is 100 times louder than a 10 decibel sound • Frequency of sound is the number of vibrations per second; frequency is measured in Hertz and described as wavelengths • Pitch is the lowness or highness of a sound
Lesson 1 continued • Sound wave energy can be absorbed and reflected; soft surfaces absorb, hard surfaces reflect and redirect (echoes) • Sounds from the same object can be adjusted in various ways e.g. striking, tension • Compression waves carry sound through air . • The sound energy transfers from particle to particle but the particles stay in place. • Sound needs a medium to carry the vibrations • The medium determines the rate of speed ;change the medium and the rate changes, warm air is faster than cold air, solids and liquids are better than gases
LESSON 2 • The sun is the source of light energy in our solar system • Light energy travels by waves, but does not need a medium to carry it. These waves are called radiation. • All the different waves are called the “electromagnetic spectrum” • The different wavelengths have differing amounts of energy but all travel at the same speed. The shorter the wave length the more energy that frequency has.
LESSON 2 CONTINUED • Light waves travel in straight lines unless interefered with . • Light can be bent (refracted), blocked, or redirected (reflected). • Light will bend when it passes throuh from one substance to another, e.g. air to water • When light is reflected its angle of incidence equals the angle of reflection
LESSON 2 CONTINUED • Opaque objects block, translucent lets some and transparent lets almost all light pass. • Lenses thicker in the middle than the edges (convex) focus light rays • Lenses thicker at the edges than the middle (concave) spread light rays