In a camera obscura, which is a Latin word meaning ‘dark chamber’, light enters a dark room or a closed box through a small hole. If the hole was small enough, a very faint inverted image would be seen on the opposite wall. At the end of the 13th century, astronomers made use of this to observe the sun. In this way they could study its hot surface, without having to look directly at it. Today, we buy a special pair of goggles to look at the sun.
Simulation programs are used for training in areas where the possibility of something going wrong is very dangerous. For instance, a trainee pilot does not fly an aircraft just after training. Before that he practices at a simulator, which behaves like an aircraft, but is on the ground so it does not crash if le pilot makes a mistake. We can also simulate a fault in a power plant or a tsunami. Trainees must demonstrate that they can handle he crisis effectively.
A CD-ROM is a plastic disc with a thin aluminium layer from which music, texts, and other data can be retrieved. Like everything else in the world of computers, these files are also stored in the numeric sequence of 1 and 0. In this case, there are tiny grooves for 1 or none for 0. A laser beam in the reader scans these grooves, which reflect the laser beam in different ways. From these laser reflections, the chip in the computer or in the CD player deciphers the data present on the CD, which could be music, text, photos, or complete programs.
‘Nano’ is derived from the Greek word ‘nannos’, which means ‘dwarf’. Everything that starts with the word ‘nano’ is usually diminutive. Nano-robots are not bigger than a thousandth of a millimetre and can be even smaller. For instance, 1 nano-metre is a thousandth of a thousandth of a millimetre. Nano-robots help doctors in difficult operations. The research that is being carried out on magnetic nano-robots suggests that they can be released in the blood and can attach themselves to cancerous growths. If a rotating magnetic field is applied to the body of the cancer patient, the small magnetic robots in the cancerous tissue would start rotating. As a result, the cancerous growth would heat up and die.
Sojourner, the small exploration vehicle that landed on Mars in July 1997, was controlled by the ground station of the American space authority NASA. Commands were sent to the Sojourner from there. It was asked to travel over the surface of Mars, take photographs, soil samples, and lots more. There were glitches too. On the first day, Sojourner collided with a rock because it was travelling too fast. And sometimes the computer onboard ‘rebooted’ so the robot ‘forgot’ what it was supposed to do.
We need access to the Internet to send an e-mail. We can get the access by paying money to an internet service provider. In addition, one needs the email address of the receiver. The e-mail starts its journey when ‘Send’ is pressed from the sender’s email account. The e-mail then goes to the service provider, who sends from one ‘node’ to another, before it reaches its destination. It may happen that an e-mail sent from Berlin, goes to USA, then to India, and finally reaches your neighbour.
[custom_search_and_filter]