It is harder to walk uphill than downhill because you must lift the weight of your body and to do this requires greater energy than that needed for walking on the level. To create this greater energy your muscles require to give extra lift, your heart has more work to do to feed the blood cells and remove their waste …

High altitudes normally begin at 1500 metres above sea level. At such altitudes, the atmospheric pressure is considerably lower than at sea level. To give some examples: the pressure at sea level is 14.7 pounds per square inch and it decreases through 4.3 psi at 30,000 ft to 1.6 psi at 50,000 ft. Because of this, the air expands as …

Long ago, the best hats and headdresses in Europe were made in Milan, Italy. A citizen of Milan was called Milaner, and although the spelling of the word has changed, a hat maker is still called a milliner, wherever he or she lives, and the hats the milliner makes are called millinery.

These interactions depend on the nature of the light and the nature of the material. For instance, light falling on a leaf encounters many pigment molecules, predominantly chlorophyll. These molecules absorb light from the red and blue ends of the visible spectrum. The remaining light is scattered back because molecules in a leaf are tightly packed and so, we see …

Ordinary glass is soda-lime glass and is a mixture of silicates of sodium, potassium, calcium and aluminium etc. It is brittle because its molecular structure is composed of tetrahedral crystals. These crystals do not have a good large-area orderly crystalline structure. Therefore, when it is under stress, the structure gets ruptured.

Albert Einstein is famous for his Theories of Relativity which say that nothing in the universe is absolutely still and that all motion is connected all or comparable. Einstein worked out a method of measuring the speed of moving objects, using the three dimension of space-length, height and thickness-and adding the fourth dimension of time. The three space dimensions tell …

As it’s a safety factor, earthing is essential and mandatory. It’s an electrical connection between the exposed metallic parts of an electrical appliance or installation and the earth, regarded to have zero potential. Proper earthing provides an alternative and easy path for leakage or faulty current to flow. It ensures that any exposed conductive part of the appliance does not …

Plaster of Paris is obtained by heating gypsum or calcium sulphate dihydrate to about 140-180 degree Celsius. When heated to such a temperature, gypsum forms Plaster of Paris. The name is derived from the large deposits of gypsum in the Montmartre hill in Paris.

By breathing we inhale air that provides oxygen. Without this gas, no life can exist. When we breathe out or exhale air, it has changed. As the air made its way through our system, some of the oxygen was used up, while the amounts of carbon dioxide and water were increased. Nature keeps a balanced supply of oxygen for our …

The Blue-ray disc uses a blue (technically violet) laser operating at a wavelength of 405 nanometre (nm) to read and write data. Conventional DVDs and CDs use red and near infrared lasers, at 650 nm and 780 nm respectively. Because the Blu-ray disc data layer is closer to the surface of the disc, compared to the DVD standard, it was …