The answer, in the modern use of the world flag, is ‘no’. The world is of Germanic origin and was used in the fifteenth and sixteenth centuries to mean a piece of cloth, or other material, displaying the insignia of a community or armed force, an office, or an individual. They were used originally mainly in warfare, and were signs …

Surgeons can cut tissues without using knives. They use a laser beam which delivers intense heat to the tissue. The beam cuts effortlessly and with total cleanliness. It also seals blood vessels so that the cut does not bleed. Eye surgery can also be carried out by laser-without cutting open the eye! The retina at the back of the eye …

It is possible that robots may begin to perform some surgical operations on people. The robot would be directed with great precision by a computer working from pictures of the inside of the patient’s body taken with scanners. The computer would be controlled by human surgeons, who would check the progress of the operation on video screens. Robot surgery could …

These animals are all represented by star patterns known as constellations. A total of 88 constellations fills the entire sky, and some of them have very odd names. The most famous constellations date back to the ancient Greeks and Romans, but imaginative astronomers have introduced additional ones since then. Among the constellations is a dragon, called Draco, coiled around the …

We think of robots as perfect machines that never do anything wrong, let alone get hurt. However, there are some robots whose whole purpose is to get hurt and to say ‘ouch’. These robots are dummy patients for dentists. They have a model human head, and student dentists practise doing fillings and other kinds of dental work on the robot’s …

On a very clear night it may be possible to see over 1000 stars without a telescope. No one knows how many stars there are in the universe.

Yes, we can have light without heat. The light from such reactions is called cool light. Many chemical reactions produce both light and heat. A burning candle is such a reaction. It is much less common for a chemical reaction to produce light without heat. Such chemical reactions are called chemiluminescent reactions, the most familiar of which occur in living …

Plants take in sunlight and combine it with carbon dioxide from the air and water and minerals from the ground. The energy of sunlight is stored in the leaves. Some of the sunlight gets stored underground. This stored sunlight is in the form of fossil fuels like coal and petroleum. Solar energy can be stored at high temperatures using molten …

When you pick up a pebble on the beach, it is hard to imagine that this solid material rock, can be bent just as though it were toothpaste. Throughout the world, however, you can find large areas of exposed rock that clearly show the evidence of bending. It is also important to realize that it is the bending and upheaval …

Bordering the southern edge of the Sahara is a region called the Sahel. It extends from Mauritania and northern Senegal through Mail, Burkina Faso, Niger and Chad into Sudan. The Sahel has an average annual rainfall of between 100 and 400 mm (4-16in) and, in the past, it was grazing land. From the 1960s, this zone has suffered droughts, so …