Polymer clays or plasticine clays are made of synthetic plastics and require âcuringâ or low heat to harden. They stay moldable for a very long time if stored properly in a plastic or metal box (no paper or fabric that would absorb the moisture). Polymer clays are usually very smooth and have a silky feeling.
On average, 4th graders are 9-10 years old because that is the normal age for the grade. But kids could potentially be anywhere from about 8 to 11 years old, since some kids hâ¦ave to repeat a year in school and get behind, and then some kids are a year ahead or have late birthdays before the cut-off date.
Report Abuse. Most kids start primary school (elementary) at around 5-6 years of age. From there it gets a little weird for middle school (jr. high), some place start it in the 6th year, others the 7th, then in high school, it starts at the 9th year, so freshmen are usually 13-14 years of age and graduate at 17 or 18.est Answer: Well, usually in Elementary School, we have 5 grades: 1st grade, 2nd grade, 3rd grade, 4th grade, and 5th grade. Junior High, or as most people call it Middle School, is: 6th grade, 7th grade, 8th grade. High school is: 9th grade(freshman), 10th grade(sophomore), 11th grade(junior), 12th grade(senior).