Category: Forces of nature

Paddle steamers are ships that are driven by a large paddle wheel present on the side or at the rear of the ship. The wheels get their energy from a steam engine, which was fired with coal in earlier times. The ship is pushed forward when the blades of the wheel dip in water and…

In a steam turbine, hot water vapours flow from jets onto a rotor having several propeller-type shovel blades. There is a high pressure in front of the turbine, while a low pressure is maintained at the back. As a result, the steam shoots at high speed through the turbine transferring its energy to the rotor.…

In a pressure cooker, the food is cooked at a higher temperature than in normal vessels. Pressure cookers are closed and air-sealed vessels that do not permit air or liquids to escape below a preset pressure. Upon heating, water evaporates inside the cooker and the steam pressure starts building up. The water then starts boiling…

Burning is a very fast chemical reaction in which a fuel combines with oxygen, releasing heat and light. Each substance has its own ignition temperature. Thus, some substances which have a low ignition temperature catch fire easily, while others with a high ignition temperature catch fire with difficulty. The size of the surface is also…

The secret of the candle lies in the wick. A matchstick ignites the wick. The heat of the flame melts the wax of the candle. The liquid wax rises up in the wick, and more it evaporates, more higher it rises. The vapour burns. Wax is made up of carbon and hydrogen. Both elements react…

A fire starts with the ignition of a substance by a source that provides the necessary heat to the substance. This source can be a matchstick, an electrical spark, or the effect of a burning lens, such as a magnifying glass. The required temperature for ignition depends on the material. Paper burns at temperatures starting…

The finer the water is sprayed on a fire, the faster it evaporates. As a result, it takes away energy from the flames and cools down the burning substance to such an extent that it can no longer catch fire again. Water extinguishes fire by creating a film of water over the burning substance, and…

Unlike a petrol engine, an air – fuel mixture is not used in a diesel engine, but instead pure air is sucked in a cylinder. The air is compressed so strongly in the cylinder that it gets heated up to 700-900°C. The diesel fuel is then sprayed finely in this hot air and immediately gets…

The Latin word fossilis means ‘unearthed’ or ‘excavated’ because we need to excavate these fuels. In other words, they are buried deep inside the Earth and we need to dig them out. Fossil fuels are made of plants and animals that died millions of years ago and were converted – by the processes inside the…

Coal is essentially made from dead plant material. Around 300 million years ago, in the Carboniferous period, huge ferns grew in the tropical climate and dead plants sank in the swamp. The dead plant layers forced oxygen out and left rich carbon deposits. The pressure of this layer pressed the water out of the remains…