The definition of a churn is a device for making butter. An example of a churn is what the Amish use to make butter. verb. To churn is defined as to stir or shake milk or cream with intense movements in the process of making butter, to stir up and agitate, or to produce something at a rapid and regular rate. An example of to churn is for a boat to create waves while moving quickly through the water .
Quick Answer. Plants absorb energy from the sun and use photosynthesis to make sugars. Animals have mitochondria that use the sugars provided by plants to produce their own cellular energy. Plants that produce their own food, and food for other plants and animals using photosynthesis, are called autotrophs.
The motion of the wind and water, as well as the motion of the wheel or shaft, represents a form of mechanical energy. The source of animal power is ultimately the chemical energy contained in foods and released when digested by humans and animals.The chemical energy contained in wood and other combustible fuels has served since the beginning of history as a source of heat for cooking and warmth.n early source of energy, or prime mover, used by humans was animal power, i.e., the energy obtained from domesticated animals. Later, as civilization developed, wind power was harnessed to drive ships and turn windmills, and streams and rivers were diverted to turn water wheels (see water power).