This model was proposed by JJ Thomson, who had also discovered the electron. It was put forth before the discovery of the nucleus. In this model, the atom is a sphere of positive charge, and negatively charged electrons are embedded in it to balance the positive charge. The electrons are like plums in a pudding. This model was rejected when …

It is the medical name for lockjaw, and is caused by the tetanus bacillus that can get into a simple wound, such as a cut, and which produces a poison that makes the muscles move in spasms. Tetanus can be treated, and it is usually dealt with by having an anti-tetanus injection.

The terminator gene is a specific genetic sequence inserted by scientists into a seed’s DNA that renders the seed and the crop it produces sterile. The seed company initiates the terminator process before selling the seeds by adding an inducer. Farmers plant seeds, grow plants and the harvest matures but the seeds are sterile. Patented by the USDA and Delta …

Taste is one of the five senses, the others being sight, smell, touch and hearing. Our chief organ of taste is the tongue, which is covered with tiny cells or taste buds. These react to different tastes and send messages to the brain. You may be surprised to learn the there are in fact only four kinds of taste: sweet, …

South of the treeless tundra in northern North America and Eurasia are huge tracts of coniferous forests, called the taiga. Most trees are evergreens, including fir, pine and spruce. These trees begin growth as soon as it becomes warm enough in spring, and they take full advantage of the short growing season. They are adapted to survive bitterly cold winters. …

Switchgrass, known in Botany as Panicum Virgatum L., is the perennial tall grass found in North America and Mexico. Its height varies from 5 ft to 12 ft, and the diameter of its stem at ground level is about 20 inches. It can grow in poor-quality soil, with low requirement of fertilisers, and can tolerate hostile conditions, including floods and …

If the percentage of sulphur is less than 0.5% in petroleum, then it is called sweet crude oil. It came to be called ‘sweet’ because the low level of sulphur gives the oil a mildly sweet taste and pleasant smell. It also contains a small amount of hydrogen sulphide and carbon dioxide.

The Mute Swan has been a domesticated bird in England for over 800 years. It is sometimes called the ‘royal’ bird and in fact by the thirteenth century all the swans in England belonged to the Crown. People were allowed to keep swans on open water as long as the birds were prevented from flying away, and they carried their …

Surface diffusion is a general process involving the motion of adatoms (adsorbed atom lying on a crystal surface, used in surface chemistry, when describing single atoms lying on surfaces and surface roughness), molecules, and atomic clusters (adparticles) at solid material surfaces. Tunnelling diffusion is a particularly interesting example of an unconventional mechanism wherein hydrogen has been shown to diffuse on …

Ploughing one month in advance i.e. in the month of May for kharif crops is known as summer ploughing. There are the three usual harvests known as the kharif or autumn (June-September), the rabi or spring (October-March) and zaid or extra harvest (March-June). Summer ploughing helps to kill weeds, hibernating insects and diseasecausing organisms by exposing them to the summer …