From picture, we can learn about wave. In the first, wave made by shocking the rope. Wave also can make when water drops into a still pond. Both of these examples tell us about wave.
While moving, the wave doesn’t carry particles of the medium; so, what is carried by a wave? A wave carries energy from one place to another. Remember, that a wave come from a disturbing movement, and moving thing has energy. To understand how a wave carries energy, look at example later.
From picture above,something in the ocean water wave that moves is the energy, not the particles of water.
So, a wave is disturbance spreading with some definite energy from one place to another. A mechanical wave is wave requiring a medium.
Kinds of waves
Depending on the motion of the medium as compared to the movement of the wave, waves are classified as either transverse or longitudinal.
1. Transverse waves.
A transverse wave is a wave which the motion of the medium is at right angles to the direction of the wave. Example: the ocean wave.
2. Longitudinal waves.
A longitudinal wave is a wave that consists of a series of compressions and rarefactions. In longitudinal wave, the motion of the medium is parallel to the direction of the wave. Example: the sound wave.
Characteristics of waves
Characteristics of waves are the ‘things’ that all waves have, they are amplitude, wavelength, and frequency.
The maximum distance the molecules in the medium are displaced from their rest position
The distance between two consecutive crest and trough of a wave.
The number of complete waves, or complete circles, per unit time. The basic unit is hertz (Hz). Frequency is usually symbolic as f ; and it is equal to one per period or
The spread velocity of waves
The spread velocity of waves is equal to the frequency times the wavelength.
Spread velocity = frequency X wavelength
v = f X λ
Or, it same as v = f X λ
When the frequency of a wave is measured in hertz and the wavelength is measured in meters, the spread velocity of the wave is measured in meters per second
Interaction of waves
Reflection is the bouncing back of a wave after it strikes a boundary that does not absorbs the wave’s energy. The incoming wave is called an incident wave. The wave that is bounced back is called a reflected wave.
The bending of waves due to a change in speed is called refraction. Refraction occurs because wave more at different speed in different medium.
REFERENCE OR CITATION:
• Hurd, Silver, & Bacher. (1993). Prentice Hall Physical Science.New Jersey: Prentice Hall, Inc.
• Serway, Raimond A. (1992). Physics for Scientist and Engineering with Modern Physics. Ifourth edition. Florida: Harcouts Brace and Company.
• Science student book grade VIII