Science > Chemistry > Atomic Structure > Rutherford’s Atomic Model In this article, we shall study Thomson’s model of an atom and its deficiencies and Rutherford’s atomic model and its deficiencies. Thomson’s Model of an Atom: J. J. Thomson, in 1898, proposed that an atom possesses a spherical shape (radius approximately 10–10 m) in which the positive charge […]
Science > Chemistry > Atomic Structure > Discovery of Proton and Neutron In last article, we have discussed, the discovery of electron and characteristics of electron. In this article, we shall discuss the discovery of proton and neutron and their characteristics. Discovery of Proton: Proton was discovered by E. Goldstein in 1886. He performed the […]
Science > Chemistry > Atomic Structure > Discovery of Electron In this article, we shall study earlier concepts of an atom, discovery of electron, and its characteristics. 600 B.C. Indian saint and philosopher Maharshi Kanad proposed that matter is made up of the smallest individual particles. He called these particles ‘paramanu’. Around 400 B.C. The […]
Science > Chemistry > Atomic Structure > Radioactivity Radioactivity was discovered by French physicist Antoine Becquerel in 1896. The phenomenon of spontaneous and continuous and uncontrollable disintegration of an unstable nucleus accompanied by the emission of active radiations is called natural radioactivity. The substance which exhibits radioactivity is called a radioactive substance. e.g. Uranium, thorium, […]
The menstrual cycle (Latin: mensis means a lunar month) is a characteristic of primates (monkeys, apes, and humans). Menstruation is defined as the cyclic discharge of blood carrying broken tissue materials through the vagina. In a human female, the fertility period extends from the age of puberty, i.e. about 11-13 years up to menopause, i.e. 45-50 years. The […]
In this article we shall study about movements and locomotion. Movements: The act of changing position or place by one or more of its parts is called a movement. Movement is one of the significant features of living beings. Animals and plants exhibit a wide range of movements. The study of movements is called kinesiology […]
Muscle is a specialized tissue of mesodermal origin. About 40-50 percent of the body weight of a human adult is contributed by muscles. They are formed by specialized elongated cells called muscle fibres or myofilaments. They have special properties like electric excitability, contractility, extensibility, and elasticity. Contractility is due to the presence of myofibrils formed by highly […]
Typhoid is a bacterial infection that can lead to high fever, diarrhea, and vomiting. If typhoid is diagnosed early, it can be successfully treated with antibiotics; if it is not treated, typhoid can be fatal. The name typhoid is given to the disease by Louis in 1829, as a derivative from typhus. Typhoid fever has received […]
The planet earth came into existence sometime between 4 and 5 billion years ago. Life evolved on planet earth about 3.5 billion years ago. The origin of life on the earth is also called photobiogenesis. Now it is clear that the life came into existence from the non-living substances. Theory of Special Creation of Origin of […]
Techniques, Procedures, and Stored Information that are useful in the identification and classification of organisms are called taxonomic aids. Herbaria, botanical gardens, museums, zoological parks (zoos) are important taxonomic aids used in the identification of plants and animals. Taxonomic aids are required because the taxonomic study of plants, animals, and other organisms is basic to almost […]