Science & Mathematics Questions & Answers

You could say because they are both spacecraft. However, the right answer is that they are both made of ceramics. Saucers are made of ceramic material called porcelain, and the space shuttle is covered with ceramic tiles that resist the intense heat of re-entry into the Earth’s atmosphere. Ceramics are materials like pottery. They are made of substances such as …

The flame of a candle is produced when the wax of the candle melts due to heat and the molten wax rises in the wick. It gets vapourised at its tip, and the vapour starts burning. The chemical reactions that occur are quite complex, giving rise to various colours and different zones of the flame. As the heated gas rises …

Generally, volume in litres is associated with liquid measurements. Space inside a car is a not a perfect cube or an easily calculable shape. Volumes are not always easy to measure for irregular solid objects or spaces. We can use litres and cubic centimetres, or even cubic metres for measuring solid objects, or space that something might fit into, for …

The Dead Sea is indeed a very scary name for a lake. It is called so because nothing lives in it. There are no sea weeds or plants, no fish either. This is because the Dead Sea is nearly six times as salty as the ocean. It also contains many other dissolved minerals, including magnesium chloride, calcium chloride and potassium …

Writing is one of the most important inventions. Humans first used brushes for writing, then thick reeds were used. Feathers were used in medieval Europe for writing. In the mid-19 century, metallic pens and nibs were widely used, while the fountain pen was produced in 1884 by the American, LE Waterman. However, these pens had a lot of problems. The …

How many hours a night do you sleep? Eight? Seven? Five? Everybody has his or her own sleep requirements. But we all do it. Until recently, scientists knew very little about why we sleep and what happens when we do. But with growing research and experimentation, we’ve learned some fascinating things about the state in which we spend nearly a …

The average salinity of sea water is about 3.5%. One cubic mile of sea water contains 166 million tonne of salt. The salts of the sea come from the breaking up of rocks and gradual wearing away of mountains releasing salts that are washed down by rainwater. It is estimated that more than 400 million tonne of dissolved salts are …

Because it is purer and fresher than air which blows overland. There are few, if any particles of dust and dirt in sea air and this enables the health giving rays of the sun to reach us more freely and powerfully. Sea air also contains vital salts and traces of iodine.

Radioactivity is dangerous because it can expose people to a harmful dose of radiation even without being aware of it. A number of small doses received over a very long time could lead to leukaemia or cancer in later life. Radiation can lead to the retention of a potentially harmful amount of radium in one’s bones. Radioactivity resulting from nuclear …

Quartz is used in watches as it acts as a piezoelectric oscillator. As a potential difference is applied across quartz, stress is generated across the perpendicular faces of the quartz crystal. It is known as reverse piezoelectric effect. The word piezo in Greek means pressure and, therefore, piezoelectricity means pressure electricity. It takes place in some crystals like quartz which …