Technology plays an important role in all aspects of our lives – the way we work, and the way we live at home. The speed of technological change in the past 100 years has been incredible.
The early telephones were large, and they didn’t even have dials or buttons. You picked up a receiver and talked to an operator who made the call for you. Nowadays, cellular telephones fit in our pockets, and we can use them to make phone calls from anywhere to anywhere. In grocery stores, cashiers used to punch keys on cash registers to enter the price of each item. These days, scanners read bar codes on products packaging, and the prices are recorded by a computerized cash register. In the past, we made a trip to the bank to deposit or withdraw money. Now we can use ATMs (automated teller machines). And many people now do their bank transactions at home online.
Modern technology has dramatically improved our lives. Personal computers enable us to create documents, store information, and analyze data – at work or at home. The Internet allows us to send and receive e-mail messages, connects us to the World Wide Web, and allows us to go shopping online from our homes. Miniature cameras that patients can swallow permit doctors to diagnose medical conditions without surgery.
“Smart homes” operated by computers turn lights on and off as people enter or leave rooms and enable homeowners to “call their houses” to turn on the heat or air conditioning. Many people feel, however, that technology has its price. With automated supermarket checkout lines, ATMs and online banking, and Internet shopping, we can meet our daily needs without having contact with other people. Life with technology can be very lonely! Also, many people are concerned about privacy. Technology makes it possible for companies or the government to monitor our use of the Internet. Our credit card numbers, bank account information, medical information, and other personal data are all stored on computers. Protecting that information will be an important issue in the years ahead. Bliss.
Do you have a favorite radio station? What do you like about it? Have you ever wondered how your radio is able to produce the sounds and the music that you like to hear? Radio programs are sent by a machine called a transmitter to your radio which is called a receiver. The programs don't travel through wires like telephone messages do. They are sent through the air over long distances by electromagnetic waves. These waves are called radio waves and were discovered by a German scientist named Heinrich Hertz. He discovered that these waves could carry sound signals. He also discovered that radio waves have different lengths. Guglielmo Marconi, an Italian, invented a microphone that changed sound waves into electronic signals, and then he developed a receiver that turned them back into sound again. He also found a way to keep waves of the same length together and keep those of different wave lengths separate. On his equipment, a radio wave looked like a letter "s" lying on its side. Short waves curved up and down more times each second than longer ones, so he divided all the waves by how many times they curved each second or by how frequently they curved. He called each group a frequency. The numbers on your radio dial are different frequencies. Different stations can broadcast their programs at the same time using different frequencies. Later, scientists found that by using only the top half of a radio wave they could reduce static and other noise that interfered with clear sound. This kind of radio transmission is called FM broadcasting because the frequency has been modulated or changed.