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 first baby teeth (also known as primary teeth) to come in are usually the lower central incisors around the age of six months. The last baby teeth to show up are the upper second primary molars, and they appear between 30 and 36 months of age. There are normally 20 baby teeth by the time a child reaches age 3.These primary teeth then remain unchanged for about three years. Not much happens to the baby teeth between 3 and 6 years of age. Between 6 and 8 years however, there is a flurry of activity as kids normally lose eight primary teeth in rapid succession.here are normally 20 baby teeth by the time a child reaches age 3. These primary teeth then remain unchanged for about three years. Not much happens to the baby teeth between 3 and 6 years of age.