Ungulates are hoofed mammals that walk on their toes. The word ungulate comes from the Latin word “unguis”, which means nail, claw or hoof. Ungulates are divided into two classes: even-toed ungulates such as deer, giraffe, antelopes, and odd-toed ungulates such as horses, zebras and rhinoceroses.

T-rays stand for terahertz radiation. It is used to scan airline passengers for explosives and illegal drugs. The rays are particularly effective, as they can see through clothing, paper, leather, plastic, wood, and ceramics. They don’t penetrate as well as x-rays, but they also don’t damage living tissue. They can read spectroscopic signatures, detecting the difference between, say, hair gel …

Transparent soaps are made of glycerin, and are partly soap and partly solvent. Sodium hydroxide causes crystals to form in soap, which is why the soap becomes opaque. In order to make it transparent, the soap has to be dissolved in enough solvent to make the crystals so small that light passes freely through, making the soap look transparent. There …

Some people become very frightened during a thunder storm, but there’s really nothing to worry about. Lightning is the result of a collision between two electrical charges one positive, and the other negative either in two clouds or in a cloud and the earth. When the difference between the two charges becomes great enough, a great spark the lightning jumps …

Most of us find telephones extremely useful for talking to others, but the telephone has several other uses. The telephone network sends voices around the world in the form of electric signals. It can also send other kinds of electric signals that are not voice signals for example, computer signals. Computer networks are groups of computers connected together by telephone …

Japanese legend says that the Sun-goddess Amaterasu ruled over the Plain of High Heaven, and her Storm brother’s empire was the sea Plain. But Susanowo, her brother, was so violent that Amaterasu hid in a cave and plunged the world into darkness. She peeped out when the gods hung a necklace and mirror in a tree, and light returned. Susanowo …

Diesel locomotive engines are classified as diesel-mechanical (DM), diesel-electric (DE) and diesel-hydraulic (DH) engines. DM engines run at an average speed of 60 kmph, while DE engines travel at an average speed of 80 kmph, also the average speed of an electric engine. The DH engines are heavy duty ones and maintain an average speed of 120 kmph.

They are air filled pockets within the skull and face bones and they are lined with mucous membrane. They open into the nose or mouth, chiefly, and they can quite easily get irritated or infected, which can be painful.

The vast coniferous forests in the northern hemisphere contain evergreen trees, including cedars, firs, larches, pines and spruces. They are all called softwoods, though some are quite hard. But most are easy to work and have many uses, including the making of paper. Deciduous, or broadleaved, trees grow in temperate lands. They include ash, beech, birch, chestnut, oak, sycamore and …

Around the continents are shallow seas covering the continental shelves. These seas contain most of the world’s chief fishing grounds, some of which are called banks. The Grand Banks, off the south-east coast of Newfoundland, Canada, extend across about 360,000 square km (139,000 square miles). With an average depth of 110 m (361 ft), they yield more than 800,000 tonnes …