Wind can be used to do work. The kinetic energy of the wind can
be changed into other forms of energy, either mechanical energy
or electrical energy. When a boat lifts a sail, it is using wind
energy to push it through the water. This is one form of work.
Farmers have been using wind energy for many years to pump water
from wells using windmills like the one on the right. In
Holland, windmills have been used for centuries to pump water
from low-lying areas. Wind is also used to turn large grinding
stones to grind wheat or corn, just like a water wheel is turned
by water power. Today, the wind is also used to make
electricity. Blowing wind spins the blades on a wind turbine –
just like a large toy pinwheel. This device is called a wind
turbine and not a windmill. A windmill grinds or mills grain, or
is used to pump water. The blades of the turbine are attached to
a hub that is mounted on a turning shaft. The shaft goes through
a gear transmission box where the turning speed is increased.
The transmission is at