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.
In general, kindergarten starts around age 5, followed by 1st grade, which would start around age 6, then all the grades in order. As a general rule, if someone is in the nth grade he or she is likely n+5 or n+6 years old. Most kids start kindergarten at age five. These are just in general. There is a window of time, several months, where a kid is on the border of meeting the cutoff age requirement.