It is the built-in skew or twist in a boomerang combined with its spinning motion that makes it return to the thrower. At first people believed that air, pressing on the lower flat surface and passing over the upper rounded face, was responsible for the return flight. But T.L. Mitchell, a Scottish explorer of Australia, gave the true explanation early …

Some animals and birds make use of tools. There are some good examples among the birds. For example, the song thrush commonly feeds on snails which it opens by flying up with the shell in its bill and dropping the snail on convenient stone. The bird often uses the same stone on a number of occasions so that it may …

The main reason we are able to float is that the density of our bodies is relatively less than the density of water. A large part of the human body is made up of air and water. Buoyancy-the ability to float depends on the individual. But with experience it is possible to improve your body balance, in other words to …

The lowest layer of the atmosphere is called the troposphere. Above it is the second layer, the stratosphere. Around the border between the two layers are strong winds, called jet streams, which blow mostly from west to east at over 160 km/h (100mph). Pilots avoid flying into them, but they often use them as tail winds, so as to increase …

Zero net is the modern strategy to regulate pollution by controlling the use of energy in constructions. The term ‘zero net energy’ is used when the amount of energy utilised by a building is equal to the amount provided by on-site or nearby renewable energy resources. Such buildings are also called zero energy buildings and are gaining popularity in US …

The word is derived from the Greek word xeros, meaning dry. It refers to landscaping which doesn’t require additional water. It uses plants which are suited to the local climate, and practitioners ensure that water doesn’t evaporate or run off. Xeriscaping is also called zeroscaping, drought-tolerant landscaping, smartscaping and waterconserving landscapes. It was developed by the water department of Denver, …

It is the use of non-human animal cells, tissues and organs in human patients. These cells can be implanted or enclosed in a device used outside the body. The tissue is harvested from animals already being butchered. Immune rejection remains the biggest challenge for this. A worrisome element of xenotransplant is the potential for infectious disease from donor animals which …

Wing Loading is the details of the distribution of pressure on an aircraft wing. An aircraft flys by producing Lift by its wings. This lift force depends on the shape of the wing that produces high pressure on the bottom of the wing and low pressure on the top. The center of the lift is usually at the 1/4 chord …

Noise that is produced by combining sounds of different frequencies together is called white noise. Since it contains all frequencies, white noise is used to mask other sounds. When two or three people talk, our brain can distinguish the sound of a particular person. But if a crowd cheers in a stadium, no individual voice can be identified. That’s white …

A wet wing is an aerospace engineering technique where an aircraft’s wing structure is sealed and used as a fuel tank. By eliminating the need for fuel bladders, aircraft can weigh less and offer improved performance. Wet wings are common among civilian designs, from airliners to small general aviation aircraft. Because tanks are an integral part of the structure, they …