Science & Mathematics Questions & Answers

The center of gravity of an object is a point at which all its weight can be considered to be located. This point is usually inside the object. However, your center of gravity may be inside or outside your body, depending on whether you’re standing, sitting, bending or falling over. If your center of gravity is over your feet, then …

We listen to weather forecasts to find out how warm and sunny, wet or windy the weather is likely to be. People in eastern Sahara, in North Africa, don’t have this problem. This is the world’s sunniest place, with an average of over 4,300 hours of sunshine a year-nearly 12 hours a day!

Deltas are plains near the mouths of some rivers, made of sediment dumped there by the rivers. The world’s largest delta is the Ganges-Brahmaputra delta, which lies partly in Bangladesh and partly in India. This low-lying fertile plain is one of the world’s most densely populated areas. It has also been the scene of many disasters when storms in the …

Many deserts-places, which have less than 25cm (10in) rainfall a year-are, in fact, dry for years and then a freak storm causes floods. Or heavy rains can transform some deserts, as in Namaqualand, South Africa, into a sea of flowers, bringing new life to seeds, which may have been dormant for years. Elsewhere, drought-resistant plants like cacti soak up rainwater …

Oases are places in deserts where there is fresh water. The largest oasis is the fertile valley of the River Nile in Egypt, which gets its water from the distant East African highlands.

The name Ark Royal goes back a long way in the annals of the British Navy. Sir Walter Raleigh, that famed Elizabethan seaman, had a great ship built which he called after himself, Ark Raleigh. She was launched in 1587. When the menace of the Spanish Armada loomed, the Crown bought her and she became Ark Royal. Probably the most …

The ceremonial drinking of tea has long been a time-honoured institution in Japan. The central idea of thee ceremony is the appreciation of the beautiful in life’s daily routine such as preparing a meal and tea, cleaning the house, working in the garden and so on. The ceremony is called in Japanese cha-mo-yu (which can be interpreted as ‘hot water …

A new industrial revolution began in the 1960s. one of its main centers is just south of San Francisco, California, USA. Here in Santa Clara County, a fertile fruit-growing region, is Silicon Valley. You won’t find this name on any map. Silicon Valley is the region between Palo Alto and San Jose where silicon chip computer technology was pioneered.

The sweet scent of flowers is designed to attract insects; who seek food in the shape of pollen and the fragrant-smelling nectar. This nectar is a solution of sugars produced in little sacs called nectarines at the base of the flower petal. The insects have a part in the process of fertilization. Almost all plants perpetuate themselves by mean of …

Maps must be revised all the time to take account of place name changes. Since 1950, many colonies have gained independence and changed place names that they associate with the past. For example, the French Colony of Upper Volta, which took its name from the River Volta, became independent in 1960, but it took 24 years before it was renamed …