Grades K–2 · Machines
How does a seesaw move one end up when the other goes down?
A seesaw has a long board resting on a support. The board can turn around a point on that support. This turning place is called a pivot.
In the diagramOne board turns around a pivotLeft end lowerRight end lowerThe arrows show linked movement, not force values.
When one end turns downward, the other end turns upward. The two ends belong to the same board, so they move together around the pivot. The support stays in place while the board changes its angle.
A push or a person’s weight can make the board turn. Where that push acts matters too. A seesaw does not make energy by itself: forces on its different parts explain why it starts, stops or changes direction.
About this explanation
Starting knowledge: Notice two ends of a board and follow a change in position.
Sources
- OpenStax — College Physics: The Second Condition for Equilibrium