In the United States, the average age for a girl to get her first period is 12. This does not mean that all girls start at the same age. A girl can start her period anytime between the ages of 8 and 15. Most of the time, the first period starts about 2 years after breasts first start to develop. If a girl has not had her first period by age 15, or if it has been more than 2 to 3 years since breast growth started, she should see a doctor.
Cancel Save! You can build a balance beam out long pieces of wood covered with thick cloth, or sand it smooth so you don't get a splinter. A piece of wood laid on the ground is not a balance beam. Balance beams are 10 cm wide, 500 cm long, and usually 124 cm off the ground. Post Your Project.
Wooden beam bridge A beam bridge is a strong, horizontal structure that rests on two end supports, and carries traffic by acting as a beam. Beam bridges are often used for heavy cars and trains to pass, and some are also built for people to walk on. Beam bridges used to be made from wood and were called log bridges. Modern ones are mostly made of steel. Beam bridges are usually placed over highways or gaps in the earth so people or cars can cross over them.