This site explains all these in very simple and easy terms. El Nino is an interesting phenomenon that occurs about every few years off the coast of Peru. When water temperatures become abnormally warm, sometimes up to eight degrees Farenheit warmer than normal, this rise in temperature changes the environment dramatically. Currents change direction, which in turn affects everything from rainfall to surface temperatures. This site with its links to many other resources will help students to the types and uses of these salts and salt solutions better.
Carbon is a very special element because it plays a dominant role in the chemistry of life.
This site will help students to understand its structure and functions in a simple and effective manner. Stories of the past will help tremendously. Science students should spend some time in reading and enjoying the many interesting ways in which The Laws of Physics have been discovered by famous scientists.