Quick Answer. An experimental variable is something that a scientist changes during the course of an experiment. It is distinguished from a controlled variable, which could theoretically change, but the scientists keep constant. Continue Reading.
While you were pregnant, your baby developed tooth buds, the foundation for baby teeth (also called milk teeth). Very rarely, a baby is born with a tooth or two, or grows a tooth in the first few weeks of life. But the vast majority of babies sprout their first tooth sometime between 4 and 7 months old.
The average child gets his first baby tooth at age six months and then gets three to four new teeth every three to four months. This continues until the second molars erupt at about age two to two and a half years, at which time your child should have all twenty baby teeth. If your child got his first tooth early or finished getting all of his baby teeth early, then he might start losing his baby teeth early too. On the other hand, if he didn't get his first tooth until age twelve or fifteen months, then he might be a little later than average in shedding or losing his first tooth.