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.
Three Year Olds. 1  Preschool's naptime is too early for 3-year-old. 2  3 year old has to lie there for 2 hours doing nothing. 3  3 1/2 year old doesn't nap anymore but preschool requires it. 4  Preschool requires naps every day, 3-y-o doesn't. 5  3-year-old not napping at preschool - she needs it.