What are waves? 1.Wave – A disturbance that transfers energy from place to place. Energy is the ability to do work. 2.Medium – The material through which a wave travels or is carried. A medium can be a gas, a liquid or a solid. Examples would be the surface of the water or sounds traveling through the air. 3.Mechanical Waves – A wave that requires a medium through which to travel. Sound and water waves are mechanical.
What are waves? 4.Sunlight – An electromagnetic wave that does not need a medium. 5.What causes a wave? – Waves are created when a source of energy causes a medium to vibrate. 6.Vibration – A repeated back and forth or up and down motion. 7.3 types of Waves – Transverse, Longitudinal, & Surface Waves
What are waves? 8.Transverse Waves – Waves that move the medium at right angles to the direction in which the waves are traveling. 9.Crests – Highest parts of the wave. 10.Troughs – Lowest parts of the wave.
What are waves? 11.Longitudinal Waves – Waves that move the medium parallel to the direction the waves are traveling. A coiled spring toy! 12.Compressions – Coils close together. 13.Rarefactions – Coils are spread out or rarefied.
What are waves? 14.Surface Waves – Are combinations of transverse and longitudinal waves. These waves occur at the surface between 2 mediums such as water and air.
What are waves? 15.Amplitude – The maximum distance the particles of the medium carrying the wave move away from their rest positions. 16.Amplitude of Transverse Waves -
What are waves? 17.Amplitude of a Longitudinal Wave – A measure of how compressed or rarefied the medium becomes.
What are waves? 18.Wavelength – The distance between two corresponding parts of a wave. For a transverse wave this distance is crest to crest or trough to trough. For a longitudinal wave it is compressed to compressed.
What are waves? 19.Frequency – The number of complete waves that pass a given point in certain amount of time. (vibrations/second) 20.Unit of Frequency – Hertz -> Hz – The number of waves passing a certain point in a given amount of time – Heinrich Hertz 21.Calculating the Speed of Waves – Speed = Wavelength x Frequency Frequency = Speed / Wavelength Wavelength = Speed / Frequency
What are waves? 22.Reflection – When a object or wave hits a surface through which it cannot pass, it bounces back.
What are waves? 23.Refraction – When a wave moves from one medium into another medium, the wave changes speed and bends.
What are waves? 24.Diffraction – When a wave moves through a hole in a barrier, the wave bends and spreads out.
What are waves? 25.Constructive Interference – 2 waves combine to make a wave with a larger amplitude.
What are waves? 26.Destructive Interference – When the amplitudes of two waves combine with each other producing a smaller amplitude.
What are waves? 27.Seismic Waves – The waves produced by earthquakes. 28. Types of Earthquake Waves – Primary (P) waves, Secondary (S) waves, and Surface waves. Surface waves are P & S waves combined. 29.Tsunamis (Tsoo NAH meez) – Huge waves on the ocean resulting from earthquakes under the ocean. 30.Seismograph – Records the ground movements caused by seismic waves as they move through the Earth. Seismographs can be used to find valuable substances such as oil, water, and minerals.