How to SeeSaw
Seesaws operate by rotating clockwise and counterclockwise. The greater the torque the greater the rotation. The effects of torque on a seesaw can be portrayed by imagining different scenarios. Imagine a small child on the left and an older teenager on the right. The child weighs about 50 pounds, which is equivalent to 11.24 Newtons. The teenager weighs about 100 pounds or 22.48 Newtons. The child is currently sitting 3 feet from the pivot point, while the teenager is 6 feet from the pivot point.
Torque = lever arm X Force perpendicular
Therefore, in the case of the child, the torque equals 11.24 multiplied by 0.91 meters, which is 10.28 Nm. In the case of the teenager, the torque is 22.48 multiplied by 6 which equals 40.91 Nm. This torque imbalance leads to the teenager rotating clockwise (towards the ground), causing the small child to go off the ground.
In order to balance one another, the torque on each side must be equal to eachother. Since the children cannot really change their weight in the moment, the solution is to change their distance from the center, thereby changing the distance of the lever arm in the equation above. Because the teenager weighs twice as much as the small child, the distance from the center for the teenager must be half the distance from the center of the child. This will create equal torques.