Friday, 3-22-13 Resonance gone bad! Resonance: a vibrating object forces some other thing to vibrate at its natural frequency and produces a larger amplitude. Resonance gone bad!
Ch. 26 RQ #1-6, pg 401 1. Source of all sounds: vibrating objects assigned last Friday, 3 points possible, write out both Q & A 1. Source of all sounds: vibrating objects 2. Pitch is subjective, but it increases (becomes "higher") as frequency increases. 3. Range of human hearing: 20-Hz to 20,000-Hz 4. Infrasonic sounds - below 20-Hz, Ultrasonic sounds - above 20,000-Hz 5. a. Compressions are regions of high pressure, while rarefactions are regions of low pressure. b. By a vibrating source 6. No sound in the vacuum of space, sound requires a medium.
Waves: from sound to light We will continue discussing sound waves and other waves, but we will now begin to shift into the more specific topic of light waves and other electromagnetic waves. Remember, all waves share the same properties of other waves: frequency, velocity, wavelength, amplitude, interference, Doppler effect, etc.
Ch. 27: Properties of Light Light is the only thing you see! All visible objects either emit or reflect light. After much deliberation, scientists now agree that light has a dual nature: part particle and part wave at the same time (thanks to Einstein). Einstein developed the idea that light is made up of photons.
Photons are massless bundles of concentrated electromagnetic (EM) energy. The distance light travels in one year is called a light-year.
Electromagnetic Waves The electromagnetic (EM) spectrum consists of: radio waves, microwaves, infrared, light, ultraviolet rays, X-rays, and gamma rays. Light is energy that is emitted by accelerating electric charges. This energy travels as an electromagnetic wave that is partly electric and partly magnetic. The range of electromagnetic waves is the electromagnetic spectrum.
The different wavelengths and frequencies of EM & light waves.
The EM Spectrum
Why was Einstein studying light?
Use your time wisely for the rest of class period: Complete today's assignment - Ch. 27 Questions, Pt 1 Be sure to submit yesterday's assignment (staple the hearing test histogram graph paper to the packet).