public library of science scientists

Hold your bag with a strap made of a thin but strong string. Now lift the same bag with another strap made of a wide cloth band. You will find that carrying a school bag with a wide cloth band is more comfortable than carrying the same with a thin strip. This is because in the second case the weigh..

One joule is the work done when the point of application of a force of one newton moves through a distance of one metre in the direction of force. 1 N m is referred as joule after the British Scientist James Prescott Joule. The letter 'J' denotes Joule. Higher units of work are kilojo..

New species can be created by domesticated animal husbandry for better and yield. For example, a new species of domestic sheep were created by hybridisation that no longer produced viable offspring with the parent species. Domestic cattle on the other hand, with several varieties such as jersey, h..

Oersted's experiment shows that a current carrying wire exerts a force on a magnetic needle and deflects it from its usual north-south position. The reverse must also be true, which was proved by the French scientist Andre Marie Ampere, who suggested that a magnet must also exert an equa..

An element is defined as a pure substance as it is made up of only one kind of atoms having the same atomic number. The smallest particle of an element is the atom, which has all the properties of that element. It cannot be further reduced to simpler substances by ordinary physical or chemical pro..

Laws of Refraction - The incident ray, the refracted ray and the normal to the surface at the point of incidence all lie in one plane. For any two given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. The above law is called Snell..

Michael Faraday the English scientist was the first person to prove that a magnet can create a current To test this he moved a magnet towards and away from the coil of wire connected to a galvanometer He observed that there was a deflection in the galvanometer indicating that a cu..

When scientists started exploring matter, they discovered that the smallest particle of an element that maintains its chemical identity through all chemical and physical changes is called and 'atom'. Just how small these atoms are can be made out if you realize that there are about 60,00..

: The incident ray, the refracted ray and the normal to the surface at the point of incidence all lie in one plane. For any two given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. The second law is called Snell's law after the h..