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.
Most babies usually get their first tooth between 4 and 7 months, but every baby is different. A few may not even get their first tooth until after their first birthday, but thereâs no need to worry about timing. Most toddlers have a full set of 20 teeth by the time theyâre three years old.ost babies usually get their first tooth between 4 and 7 months, but every baby is different. A few may not even get their first tooth until after their first birthday, but thereâs no need to worry about timing. Most toddlers have a full set of 20 teeth by the time theyâre three years old.