Science June 9 th 2020.

INTERNATIONAL KOREAN CHRISTIAN ACADEMY

Ms Castillo.

Topic: Effets, propagation and importance of sound.

There are several important factors which affect the propagation of sound: geometric spreading, atmospheric effects, and surface effects.

The Propagation of sound. Sound is a sequence of waves of pressure which propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). During their propagation, waves can be reflected, refracted, or attentuated by the medium.

Only the disturbance produced by the vibrating body travels through the medium but the particles do not move forward themselves. The matter or substance through which sound is transmitted is called a medium. A medium is necessary for the propagation of sound waves. The medium can be solid, liquid or gas.

Sound waves with specific frequencies and intensities can have positive effects on various plant biological indices including seed germination, root elongation, plant height, callus growth, cell cycling, signaling transduction systems, enzymatic and hormonal activities, and gene expression.

Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed. The minimum distance in which a sound wave repeats itself is called its wavelength.

Sound waves in water, bottom of sea

A sound wave propagating underwater consists of alternating compressions and rarefactions of the water. These compressions and rarefactions are detected by a receiver, such as the human ear or a hydrophone, as changes in pressure. These waves may be man-made or naturally generated.

ACTIVITY: Read the text and answer the following questions: 

1- What is sound propagation?

2- What are the factors that affect the propagation of sound?

3- What is the most important requirementfor the propagation of sound?

4- What is the effect of the sound on plants?

5- What are the characteristics of sound?

6- How does sound propagate in water?

NOTA: Enviar la asignación el día miércoles 10 de Junio.