the old-fashioned secret behind modern technology
have you heard of Gulielmo Marconi? He is said to have invented radio at the end of the nineteenth century. Until television became widespread, radio was one of the baic means of communication and entertainment. The simple tranistor radio may seem a little old-fashioned in these days of mobile phones, laptop computers. and ipods. However,radio waves, which are invisible and undetectable to humans, have changed the world completely. When you use aa mobile or cordless phone, a wireless network for your laptop, or switch tv channels by remote control, you are using radio waves.