Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major formsâ white phosphorus and red phosphorus âbut due to its high reactivity, phosphorus is never found as a free element on Earth. Instead phosphorus-containing minerals are almost always present in their maximally oxidised state, as inorganic phosphate rocks.
Ages & Stages â Preschool Children. Three and four-year-old children are often called preschoolers. Preschool children want to touch, taste, smell, hear, and test things for themselves. They are eager to learn. They learn by experiencing and by doing. Preschoolers learn from their play.
Childcare centers are generally an option for working parents who need their children to be taken care of during the day; centers accept babies as well as toddlers and are full-time, full-year programs. Preschool refers to an early-childhood educational class for 3- and 4-year-olds. Many offer a part-time schedule (for example, a few hours a day, two to five times a week) as well as full-day care, but only from September to May. Yet the terms are often used interchangeably.