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.
Many parents worry about when their children will sprout their first baby tooth, also knows as primary teeth. The average time to expect a first tooth is between 4 and 7 months of age. However, every child is different and timing and appearance will vary among each one. The two, front bottom teeth usually appear first. Most parents do not look forward to teething babies expecting they may be fussy or uncomfortable.