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.
Plants absorb energy from the sun and convert it into chemical energy. Herbivores get energy by eating plants while carnivores get energy by eating herbivores and other carnivores. Trace the energy back to the source and you arrive at the sun. But converting solar energy into electricity is tricky. Photovoltaics can do the trick. These are materials that can absorb photons -- the basic quantum units of light -- and convert them into electricity. Edmond Becquerel discovered the photovoltaic effect in 1839 while experimenting with an electrolytic cell.