Naturally occurring food and fuel contain complex carbon-based molecules, chiefly derived from plant matter that has been formed by photosynthesis. The chemical reaction of these molecules with oxygen releases energy; such reactions provide energy for most animal life and for residential, commercial, and industrial activities.
. The expression “produce energy” typically refers to the conversion of stored energy into a desired form for practical use—for example, the stored energy of water behind a dam is released so that it flows downhill and drives a turbine generator to produce electricity. Food and fuel also release energy when they are digested or burned. When machines or animals “use” energy (e.g., to move around), most often the energy is transferred to heat the surrounding environment.
The energy released by burning fuel or digesting food was once energy from the sun that was captured by plants in the chemical process that forms plant matter (from air and water). (Boundary: The fact that plants capture energy from sunlight is introduced at this grade level, but details of photosynthesis are not.)
Energy Flows and Matter Cycles. Primary Producers – autotrophs capable of converting solar energy into chemical energy (plants, photosynthetic protists,
The sun is a very powerful source of energy. People are always trying to harness it to make electricity, warm their houses, heat their water etc. Plants figured out how to use solar energy millions of years ago to make their food. They use the light energy from the sun (solar energy) and convert it into chemical energy that is stored as sugar (glucose) in the plant. Excess glucose is stored as starch in the leaves, roots, stems and seeds of the plant. The energy from the sun is transferred to the plants. This energy is then passed to animals when they eat plants. Whenever the plant needs energy it breaks down its stored glucose for its life processes
In order to do this though they need energy – which they get from sunlight. The energy from sunlight (solar energy) is used by the plant to make carbon dioxide and water and change into glucose (food) and oxygen. This process is called photosynthesis. The word photosynthesis comes from two Greek words: photo meaning light and synthesis meaning putting together so photosynthesis means “putting together with light”.
Most plants contain a special colored chemical or pigment called chlorophyll that is used in photosynthesis. Chlorophyll is what absorbs the sun's energy and turns it into chemical energy. Not all the light energy from the sun is absorbed.
Sunlight has many different colors in it. Chlorophyll usually absorbs red and blue light from the sun and reflects green light. It's the green light reflecting that makes some leaves look green! In the fall, some plants stop producing chlorophyll and we see leaves change color. With the chlorophyll gone, the green light is not being reflected anymore!
. The chemical reaction by which plants produce complex food molecules (sugars) requires an energy input (i.e., from sunlight) to occur. In this reaction, carbon dioxide and water combine to form carbon-based organic molecules and release oxygen. (Boundary: Further details of the photosynthesis process are not taught at this grade level.)
Plantsuse a process called photosynthesis to make food. During photosynthesis,plants trap light energy with their leaves. Plants use the energyof the sun to change water and carbon dioxide into a sugar called glucose.Glucose is used by plants for energy and to make other substances likecellulose and starch. Cellulose is used in building cell walls. Starchis stored in seeds and other plant parts as a food source. That's why somefoods that we eat, like rice and grains, are packed with starch!
Nuclear fusion processes in the center of the sun release the energy that ultimately reaches Earth as radiation. The main way in which that solar energy is captured and stored on Earth is through the complex chemical process known as photosynthesis. Solar cells are human-made devices that likewise capture the sun’s energy and produce electrical energy.