UNIT 3. PHYSICS OF WAVES, ELECTRICITY AND MAGNETISM

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vibration, n. 
/vaɪˈbreɪʃən/ 
вибрация 
visible, adj. 
/ˈvɪzəbl/ 
видимый, зримый, syn. 
visual 
 
 
READING 
Read and translate the text using a dictionary if necessary: 
Physics is a specific area of study in the field of science that focuses on 
the makeup and properties of both energy and matter, as well as how the
two interact together. The most basic and significant matters in physics are 
the study of light and sound. A lot of more advanced principles and studies 
in the realm of physics lead back to general knowledge about the way both 
of these function. One of the most important facts to understand about both 
light and sound is that both are forms of energy that move in waves. While 
they are both forms of energy that travel in the form of waves, there are
vital differences between sound waves and light waves. 
Sound and light travel at significantly different speeds. Light waves 
move at speeds that are nearly one million times faster than sound waves
are capable of traveling. Light waves are capable of moving through empty 
space at speeds of around 186,000 miles (or 299,792,458 meters) per 
second. This is faster than most humans can even begin to comprehend.
This is also the reason behind the expression, «faster than the speed of 
light». In the field of physics, the term «light» is usually used to refer to 
electromagnetic radiation. 
However, there are various other types of light. Other forms of light 
include infrared light, ultraviolet light and light that is visible to humans, 
known as visible light. Each type of light has different wave length 
frequencies, some being high and some being low. The frequency of the 
light determines if it is detectable by the human eye, although humans are 
capable of seeing different types of wave lengths than other species. Insects 
such as bees and spiders, for instance, are capable of viewing ultraviolet 
light, while reptiles like snakes can view some infrared lights. Some 
mammals, like monkeys, are capable of seeing the same light as humans. 
Others, like dogs, see similar light but view fewer colors that are a lot 
dimmer than humans perceive them to be. Dogs often perceive light and 
colors as a dull yellow, blue or gray. The main key to understanding light is 
in realizing that light is all around, in many forms, although humans are 
simply unable to view most types with their eyes alone. 

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Sound waves are much different than light waves in the manner in 
which they travel. Sound waves move much slower than light waves at 
speeds of about 1,125 feet (about 340 meters) per second. Sound waves are 
also different in the sense that they travel through any type of substance, 
whether solid, liquid or gas, whereas light travels best through empty space. 
When sound waves hit materials, they cause vibrations. These vibrations are 
either high frequency or low frequency. Low frequency sound waves 
produce low tones while high frequency waves create high-pitched tones. 
When the frequency of the sound waves changes, it creates a change of 
pitch in the sound that is heard by the human ear. As with light waves, the 
level of sound wave frequencies that can be perceived is dependent upon the 
capability of the species body. Humans are actually not among the greatest 
hearing species in the world. Human ears are only capable of hearing 
frequencies of about 20 kilohertz (a form of measuring frequencies), while the 
species that is known to have the highest capability of hearing, the Greater
Wax Moth, can hear frequencies of around 300 kHz. As with light waves, it is 
also important to remember that sound waves are everywhere, despite the fact 
that human ears are incapable of hearing many sounds. 
Understanding the speed of light and sound, the way they travel and 
how they both operate is vital knowledge to have when it comes to pursuing 
more complex subjects in physics such as radiation and atoms. 
(Adopted from 
www.boogeylights.com 
) 
 
 
 
 

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