What is another source of energy besides the sun that gives plants energy to grow?

we have a scince project (in french..) an we have to make a food chain with 4 organisms + an energy source besides the sun then we have to explain why we chose that energy source instead of the sun..

What is another source of energy besides the sun that gives plants energy to grow?
This is more of a botony question than one for astronomy.





School questions are normally asked because the students would generally be able to deduce the answer from previous lessons. You may wish to review your past lessons to find this answer. Yahooanswers is not a good place to turn to for school answers.





Plants do need sunlight for photosynthesis. If sunlight is not present, the plant will wilt and die. Sunlight may be substituted by incandescent or florescent lights.





Certain colors in light rays are more important than others for proper plant growth. Leaves reflect and derive little energy from many of the yellow and green rays of the visible spectrum. The red and blue parts of the light spectrum are the most important energy sources for plants, and plants require more rays from the red range than from the blue.





What are the best sources of these colors besides the Sun?





Incandescent light produced by ordinary light bulbs in our homes are not particularly good. They are a good source of red rays but a poor source of blue. They produce too much heat for most plants and, if used, must be kept away from the plants, thus reducing the intensity of the light the plants receive.





Fluorescent tubes provide the best artificial light sources available for plants in the home. Other light sources such as sodium lamps may be used but are not normally available or adaptable for home use.





Many indoor gardeners use cool white fluorescent tubes. Warm white fluorescent tubes also seem fairly effective, but fluorescent tubes listed as white or daylight are less desirable for indoor plant growth. Cool white tubes produce a small amount of red rays in addition to orange, yellow-green and blue rays. However, the red light produced usually is not enough for many plants unless windows or other artificial lights produce additional red rays. A few incandescent bulbs in the growing area can furnish needed red rays. A general ratio of incandescent to fluorescent light is about 3 to 10, so for every 100 watts of fluorescent light, you should provide about 30 watts of incandescent light for a better red to blue light balance.





Special fluorescent tubes also have been developed for growing plants. These have a higher output in the red range to balance the blue output. Many home gardeners have found that these tubes can be used in combination with cool white tubes. Use one special plant-growing tube to each one or two cool white tubes. This method is more economical than using all special tubes, since cool white tubes cost less than the special plant-growing tubes. Also, fluorescent plant-growing tubes use less electricity and produce less heat than incandescent bulbs, and you will not have to provide fixtures for both incandescent bulbs and fluorescent tubes.





Spotlights are less effective than fluorescent lights.





Your choice may be dependant upon budget. Otherwise here are some differences between artificial light sources for plants:





Incandescent lamps lay at the low end of the pricing spectrum for plant lights. A good 150 watt bulb will only set you back about $5 but isn't necessarily your best bet for starting a large garden indoors.





Fluorescents are a poor choice for flowering and budding plants because of their low lumen (brightness per unit of energy consumed), but they are a great source for herbs and other plants that don't need a lot of light for under $40.





T5 fluorescents are more compact and efficient than older forms of fluorescent lighting which allows them to be used for all plants rather than just for seedlings. Key advantages of these high-end fluorescents include: more of their light is used by the plant, they produce less heat than incandescent and HID grow lights and consequently can be placed much closer to the plant.





High Intensity Discharge Lamps. They are the brightest bulb in the box and very efficient, but expect to pay for the advantages. One 1,000 watt HID lamp can produce the same amount of light as 50 40-watt fluorescent lights.





Within the HID category there are several types of bulbs: High Pressure Sodium, Metal Halide, Low Pressure Sodium and Mercury Vapor. The only ones that indoor gardeners need to concern themselves with are High Pressure Sodium or Metal Halide. They most commonly come in sizes such as 400 and 1,000 watt. The 400 can supply enough light for a growing area of about 15 square feet or a 4 x 4 foot garden. The 1,000 watt lamp can cover an area of about 7 x 7 foot. For fast growth, use about 25 watts of HID light per square foot.





Metal Halide light is blue-white in color and is good for leafy growth and keeping plants compact. It is best used as a primary light source. They produce up to 125 lumens per watt compared to 39 lumens per watt for standard fluorescent lights and 18 lumens per watt for standard incandescent bulbs.





High Pressure Sodium light is red-orange and is best for flowering plants and as supplemental light. It's economical since its average lifespan is twice that of Metal Halides. High Pressure Sodium bulbs produce up to 140 lumens per watt. Their major disadvantage is that they don't produce light that falls within the blue spectrum. If a High Pressure Sodium light was the sole source for a plant, the plant would grow up thin and lanky, which is not the type of plant that most gardeners want.





Most plants and vegetables need about 10 to 12 hours of light per day in order to grow. Plants that produce fruit or flowers will need more: up to 16 hours a day. Most plants should be located with the tips of the plants 6 to 12 inches from the light source. The intensity of light drops rapidly as the distance from the light bulbs or tubes increases. Fluorescent tubes also do not produce as much light at the ends as they do in the center. Therefore, the brightest spot under a fluorescent fixture is directly beneath the center of the tubes.
Reply:In nature there are only 2 energysources life can use. They are the sun and, in total absence of sunlight, geothermal heat. On the bottom of the oceans, along geothermal vents called black smokers, and in some caves there are entire ecosystems that live off this heat and the chemistry produced while elsewhere life is completely dependent on sunlight either directly, as in photosynthesis, or indirectly for animals.
Reply:Carbon dioxide, plants feed off carbon dioxide and through the process of photosynthesis releases oxygen.