Principles of Earth and Physical Science Mr. Taylor Rainier Jr/Sr High School

 Sound waves are caused by vibrations and carry energy through a medium. Sound waves are longitudinal (push-pull) waves  The medium is the material that conducts the energy from particle to particle. The speed of sound varies with the medium In general, more solid media conduct sound faster.

 Loudness is determined by intensity (amplitude) Loudness is measured in decibels.  Pitch is determined by frequency High pitched sounds have high frequency Humans hear from about 20Hz to 20,000 Hz Lower than 20Hz = infrasound Higher than 20,000Hz = ultrasound

 Most musical instruments produce sounds by vibrating strings, membranes, or columns of air. Instruments produce a fundamental frequency and multiples of that frequency called harmonic frequencies.  Musical instruments amplify these frequencies by forcing vibrations of the instrument body (resonance).

 The ear uses resonance to vibrate nerve endings. Vibrations are transmitted by the eardrum to the inner ear where the nerve endings reside in the cochlea.  Distances can be detected by measuring the reflection of sound waves Ultrasound Sonar

 Light can be modeled as a wave, or a particle.  Light as a wave follows the characteristics we have been discussing: Reflection, refraction, diffraction, interference, etc. Light acts as a transverse electromagnetic wave

 Light can be modeled as a wave, or a particle.  Light as a particle is described as “packets of energy called photons. A photon has energy related to its frequency:  High frequency is high energy  Low frequency is low energy

 The speed of light varies with the medium: In a vacuum light travels at approximately 3x10 8 meters/second (186,000 miles/second)  The brightness of light varies with intensity and is often measured in lumens.

 Light is part of the electromagnetic spectrum

 Light is both absorbed and reflected from any surface it hits.  The Law of Reflection: The angle of incidence = the angle of reflection. The “normal” is a right angle to the surface.

 Mirrors reflect light Flat mirrors create a virtual image. The image looks like it is behind the mirror, but not light rays are located there. Curved mirrors create a distorted image.  Concave mirrors curve in  Convex mirrors curve outward  Convex mirrors can create a real image. This is how light is focused from a projector onto a wall/screen.

 Colors depend on the wavelength of light striking the eye.  The color of any object is a result of the light they reflect or transmit.  Transmitted light has 3 basic colors: Red Green Blue  All colors are a result of mixing these 3 colors of light

 Colors depend on the wavelength of light striking the eye.  The color of any object is a result of the light they reflect or transmit.  Reflected light has 3 basic color pigments: Yellow Cyan Magenta  All colors are the result of mixing these 3 basic pigments.