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.
Age Range. Most babies get their first tooth between the ages of 4 and 7 months, according to the Healthy Children website. Usually, the bottom two front teeth emerge first, followed by the top two front teeth. The molars and the teeth on either side of the front teeth will fill in during the next several months.