4to40.com

How long do people live?

The average lifespan of people varies from country to country. If you live in a developed country, then you can expect to live longer. For example, Australians live, on average, 76 years, West Germans and North Americans 75 years and Britains 74 years. In poorly developed countries, where many people do not have enough to eat, suffer many diseases and …

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How is the time difference between two countries calculated?

The earth has 360 imaginary lines called longitudes or meridians running vertically between the poles. Each of these longitudes is called a degree. The 0 degree longitude passing through Greenwich, near London, is considered as standard and the time of all other time zones are calculated accordingly. The time difference between each longitude (each degree) is 4 minutes. So if …

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How is the temperature of a star measured?

As stars are very far away, their temperature cannot be measured directly. Fortunately, the light coming from stars can be analyzed through several scientific instruments. Although all stars appear white, they have different colours when carefully viewed. The variations are a result of their temperature – cold stars appear red, and hot ones blue or white. The colour of a …

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How is the mass of heavenly bodies measured?

The mass of a heavenly body can be measured by knowing the orbital period (time it takes to complete one orbit around the other body), the distance between two bodies and gravitational constant. The orbital time is inversely proportionate to the square root of the sum of the masses of two bodies and directly proportion distance raised to power three …

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How is the height of water tides predicted?

As astronomical data is not sufficient to calculate tides, predictions are also based on actual tidal measurements in many areas, over an extended period. A network of tide stations is equipped to take the following measurements every six minutes: tide levels, wind speed and direction, water current speeds, directions, air and water temperatures and barometric pressure. Stations that provide these …

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How is the distance between planets calculated?

The distance between planets was calculated by Copernicus using Kepler’s Third Law of Planetary Motion. According to Kepler’s Law of Motion, the square of the time period of the revolution of a planet around the sun is directly proportional to the cube of the semi-major axis of its orbit. Using this law, the distance between planets can be calculated.

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How is Paper Perfumed?

Fruity, musk, floral, woodsy… believe it or not, the human nose can detect the difference between nearly 1,000 different odours. Our nose is very sensitive to delicate variations in smell. To cater to the need ‘to smell good’, perfume manufacturers churn out innovative new fragrances all the time. Perfume manufacturers spend a lot of money on making a perfume, research, …

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