Understanding the basic properties of waves.pptx
- 1. Introduction to Waves Prester John
- 2. Objectives Learn the basic characteristics of waves and use them to solve simple problems.
- 3. What Are Waves? A wave is a disturbance that carries energy through matter or space without transferring matter. Wave Demo
- 4. Ocean Waves
- 5. Wave Characteristics Amplitude: The greatest distance from equilibrium. The bigger the amplitude of the wave, the more energy the wave has.
- 6. Wave Characteristics Crest: The top point of a wave. Trough: The bottom point of a wave.
- 7. Wave Characteristics Wavelength: The shortest distance between points where the wave pattern repeats itself. Wavelength is measured in meters, the symbol is
- 8. Wave Characteristics Phase: Any two points on a wave that are one or more whole wavelengths apart are said to be “in phase”.
- 9. Wave Characteristics Frequency: Is the number of complete oscillations a point on that wave makes each second. Frequency is measured in Hertz (Hz), its unit is
- 10. Wave Characteristics Speed: The speed or velocity of a wave is how fast the energy is moved. For most waves, wave speed does not depend on amplitude, frequency, or wavelength. Speed depends only on the medium through which it moves.
- 11. Wave Characteristics Period: The time it takes a wave to go through one cycle, or the time it takes a point to go through one phase of the wave. The period of a wave is measured in seconds, and it’s symbol is “T”.
- 12. Example 1 What is the velocity of a wave that has a frequency of 250Hz and a wavelength of 1.5m?
- 13. Example 2 How does the speed of a wave change if the amplitude is increased? The speed doesn’t change. What is the velocity of a wave that has a frequency of 100Hz and a wavelength of 2.0m?
- 15. Objectives Learn how to draw a wave diagram Learn about the different types of waves. Study, create, and destroy different wave types.
- 16. Try these! Draw the following waves on the same graph: 1. A wave with an amplitude of 6m and a wavelength of 3m. 2. A wave with an amplitude of 2m and a wavelength of 2m. 3. A wave with an amplitude of 3m and a wavelength of 4m.
- 18. Waves transfers energy but not matter Recall!
- 19. Classification of waves Waves can be classified based on their characteristics. Some common types of waves include: 1.Mechanical waves 2.Electromagnetic waves 3.Transverse waves 4.Longitudinal waves 5.Surface waves
- 20. Waves Movement of waves may or may not require a medium.
- 21. Examples of waves Water waves light waves Sound waves microwaves
- 22. So what’s a medium? A medium is a channel through which waves travel. It could be any form of matter (solid, liquid, or gas!) In a water wave, the medium is the water. In a sound wave, the medium is the air. In an earthquake, the medium is the ground.
- 23. Waves that requires a medium to travel are called mechanical waves Examples: Sound waves Seismic waves Water waves 1. Mechanical waves
- 24. 2. Electromagnetic Waves Electromagnetic waves do not require a medium They can travel through space (or vacuum). They are mostly caused by disturbances in electric and magnetic fields. Examples: Radio waves Light waves Infrared waves Ultraviolet waves X-ray Gamma rays
- 25. Question What happens when waves travel through a medium? Answer They transfer energy. Example Sound traveling in your ear causes vibration in your ear Test yourself
- 26. 3. Transverse waves In transverse waves, the direction of wave particle is perpendicular to the wave direction. Transverse waves can be modelled by moving one end of a slinky up and down. Each coil represents a particle. source moves up and down direction of wave propagation coils vibrate up and down
- 27. 4. Longitudinal waves In longitudinal waves, each particle oscillates parallel to the direction of propagation of the wave. There is no vertical movement. Longitudinal waves can be modelled by moving one end of a slinky back and forth. Each coil represents a particle. source moves left and right coils vibrate left and right direction of wave
- 28. Within longitudinal waves, regions in which the particles are relatively close together are called compressions, and regions where they are relatively far apart are called rarefactions. Sections of longitudinal waves compression rarefaction
- 29. Transverse and longitudinal waves
- 30. Transverse vs. Longitudinal Waves
- 31. The wavelength of a longitudinal wave can be measured as the distance between the center of two compressions or rarefactions.
- 32. 5. Surface Waves -These waves occur at the boundary between two different mediums. -They can be transverse or longitudinal. - They move in circular motion -Example Ocean waves.
- 34. Facts to note!! Mechanical waves can be transverse, longitudinal , or surface waves Electromagnetic waves will only be transverse.
- 35. Checkpoint 1. What is a Transverse wave? 2. What is a Longitudinal wave?
- 36. 1. What is the wavelength of a sound wave with a frequency of 50 Hz? (Speed of sound is 342 m/s) 2. A sound wave in a steel rail has a frequency of 620 Hz and a wavelength of 10.5 m. What is the speed of sound in steel? 3. Determine the frequency of a microwave 6.0 cm in length. (A microwave is an electromagnetic wave. It travels through space at a speed of 3.0 x 10 ^8 m/s) 4. What is the period of the microwave in problem 3? Word problems
- 37. Class Test 1. If a wave is moving toward shore with a velocity of 36 km/h and it has a frequency of 2.5 hertz, what is its wavelength? 2. If a tuning fork has a frequency of 320 hertz and the wavelength of the sound it produces is 150 cm, what is the velocity of the wave. 3. The speed of light in a vacuum is 1.08 x 109 km/h. Red light has a wavelength of 7 x 10-7 , what is its frequency in a vacuum? 4. The frequency of violet light is 7.5 x 1014 hertz. What is its wavelength in a vacuum? (speed of light = 3.0 x 108 m/s.) 5. If a jump rope is shaken fast enough to produce a wave with a wavelength of 5 x 10-3 km and the crest of the wave