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.
It's a scale ! The triple-balance beam scale is the standard tool used for measuring the mass of small objects. It will give you a precise measurement in kilograms. Things You'll Need: o Triple-balance beam scale. o Object. o Pen. o Paper. What To Do: 1  Empty the plate. 2  Place an object on the scale pan. 3  Move the slider on the beam to the estimated weight of the object. 4  Look at the left side of scale where the 0 indicator is located. 5  When the arrow points to 0, look at the three beams. 6  Take the object off the pan and measure it again.