If you have an outdoor thermometer, look out the window to see how cold it is outside. Another kind of remote sensing is NASA's weather satellites that tell us about weather on the Earth. For farming, remote sensing uses pictures taken by airplanes flying back and forth over a field. The pictures are special ones that show how much heat there is in different parts of the field. Scientists know that plants try to use as much energy as they can.
Plants also try to stay as cool as possible.
That means plants try to grow the most, biggest leaves they can. More and bigger leaves mean more water evaporates from them. This shows up in the pictures taken from the airplanes. That means scientists can tell how well the plants are growing in each part of a field. Farmers have sought this ability for 30 years.