Windmill Forces

The science background gives teachers more in-depth information about the phenomena students explore in this unit. Below is an excerpt from the background information on windmill forces.

Wind has energy because it is moving air molecules. As cold air sinks in the atmosphere and warm air rises, it creates wind. Remember that energy is the ability to do work. Work is any change in position, speed, or state of matter due to force. Unlike matter, energy is not made up of atoms. However, matter and energy are constantly interacting. In the same way that all organisms need energy to survive, grow, and reproduce, matter can only change when enough energy is present.

There are different forms of energy, which is never created or destroyed. Instead, it transforms from one form to another. Energy is always either being stored or doing work. Energy that is stored is called potential energy. For example, all matter has a form of potential energy called chemical energy. This energy is stored in the bonds of atoms and molecules. The reason we eat food is because food contains chemical energy. This chemical energy was once light energy from the sun. Plants and other producers capture the sun’s energy and during photosynthesis, turn it into chemical energy stored in glucose, which living things need to survive.

Energy of motion is called kinetic energy. The more kinetic energy something has, the more work it can do.

Windmills are able to pump water in the Netherlands because windmills are structures that capture the wind’s kinetic energy to do work. This is possible because wind produces a force when it hits the windmill’s blades. Remember that a force is a push or pull that acts on an object, changing its speed, direction, or shape.

Without force, nothing can move. When all of the forces acting on an object are balanced, the object will not change its motion. Balanced means that all of the forces acting on an object are equal. Unbalanced means that the forces acting on an object are not equal. If you want to change an object’s movement, there has to be an unbalanced force acting on it. An unbalanced force can change the speed or direction of the object. Wind provides the unbalanced force that moves the windmill’s blades.

When the force of the wind hits the windmill’s blades, the force transfers some of the wind’s kinetic energy to the blades. When energy is transferred, it moves into or out of an object or system. This transfer of energy causes the blades to turn powering a pump.