WAVES

THE NATURE OF WAVES TYPES OF WAVES: 1. Transverse—matter moves back and forth at right angles to the direction that the wave travels 2. Compressional (Longitudinal)—matter in the medium moves back and forth in the same direction that the wave travels

WAVE PROPERTIES 1. PARTS OF A WAVE: A.Transverse wave 1. crest 2. trough 3. wavelength B. Compressional (Longitudinal) wave 1. compression 2. rarefaction 3. wavelength

2. Frequency A. the number of waves that pass a point in one second B. measured in hertz (Hz) 3. Wavelength A. the distance between one crest to the next crest B. measured in meters (m) 4. Amplitude A. the energy of the wave

5. Speed of waves A. measured in meters per second (m/s) B. velocity = frequency x wavelength C. v = f x λ

THE BEHAVIOR OF WAVES 1. Reflection 1. angle of incidence equals angle of reflection 2. Refraction 3. Diffraction 4. Interference 1. constructive—new wave is larger than the 1. constructive—new wave is larger than the original waves original waves 2. destructive—new wave is smaller than the original waves original waves

SOUND WAVES SOUND WAVES A. Compressional (longitudinal) wave B. The speed of sound is slower than the speed of light C. Needs a medium to travel through D. Travels fastest in a solid and slowest in a gas E. Travels faster as the temperature of the medium increases

Applications of sound Sonar—used to find things under water Sonar—used to find things under water Ultrasound—used to look at soft body tissues and treat medical conditions Ultrasound—used to look at soft body tissues and treat medical conditions Echolocation—bats and dolphins use to find food Echolocation—bats and dolphins use to find food

ELECTROMAGNETIC WAVES AND LIGHT WAVES LIGHT WAVES: A. transverse waves B. travel slowest in solids and liquids and fastest in gases or empty space C. does not require a medium to travel through

ELECTROMAGNETIC WAVES –Are light waves –All types of electromagnetic radiation travel at the speed of light, but differ in wavelength –Are arranged on the electromagnetic spectrum by wavelength –The higher the frequency, the shorter the wavelength –the lower the frequency, the longer the wavelength

TYPES OF ELECTROMAGNETIC WAVES Radio Waves Radio Waves –Longest wavelength, lowest frequency –Radio, microwave, RADAR Infrared Waves Infrared Waves –Warmth you feel – remote control Visible Light Visible Light –Colors of the rainbow (ROYGBIV) –Light you can detect with your eyes

Ultraviolet Light Ultraviolet Light –From the sun –Can damage the skin –Kills bacteria X-Rays X-Rays –Photograph bones Gamma Rays Gamma Rays –Most dangerous of all the electromagnetic waves –Shortest wavelength, highest frequency –Therapy used to kill cancer cells

MIRRORS –Concave Curve inward Curve inward Used to magnify objects Used to magnify objects Example: make-up mirror Example: make-up mirror –Convex Curve outward Curve outward Image is upright and smaller Image is upright and smaller Allow you to see a large area Allow you to see a large area Example: store mirror Example: store mirror

LENSES –Convex Thicker in the center Thicker in the center Light bends toward the thickest part Light bends toward the thickest part Example: microscope, magnifying glass Example: microscope, magnifying glass –Concave Thinner in the center Thinner in the center Light bends toward the thicker part of the lens Light bends toward the thicker part of the lens Example: telescope Example: telescope