Locate placeholder image so we can use it to position the scrollers. Sources of crude oil and natural gas Page 3 Figure 4. Cross section of porous sandstone. The dark shading indicates the spaces that contain oil. When you burn oil or gas, they heat the surroundings.
Energy is transferred from the chemicals to the surroundings.
The original source of this energy is the Sun. Plants use the Sun's energy to produce sugars and oxygen from carbon dioxide and water, during photosynthesis. This energy is stored in the chemicals the plant produces. Animals eat the plants and so the energy is transferred to their bodies. In the conditions on Earth millions of years ago, plants and animals decayed, and the organic chemicals their bodies were made of became the source of fossil fuels we now use.