Science Encyclopedia for Kids


We all use it. In fact, we use it every day. It powers our machines, heats our buildings, and lights our homes. Without it, transportation in our modern world would be nearly impossible. What is it? You probably already guessed that it is energy. Energy powers our lives. Energy is the ability to do work, and we use it to produce everything we have. Finding enough energy to meet the demands of an …

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Energy Sources

According to the U.S. Energy Information Administration, nonrenewable energy sources, including fossil fuels and nuclear power, provide more than 92 percent of the world's energy needs. Renewable energy sources contribute just over seven percent. …

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The Problem with Fossil Fuels

The world depends on fossil fuels. Inexpensive fossil fuels have improved the quality of life for many people. Try to imagine what life might be like without gasoline to power our vehicles, or coal to produce electricity. So, what's the problem? Let's begin with pollution. Fossil fuels take a toll on the environment. They cause obvious problems such as oil spills and smog filled air…

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Back to the Future

There is another problem with fossil fuels. Remember, they are a nonrenewable energy source. Experts say the world's fossil fuel supplies are dwindling. They could be gone within the next 50 to 100 years, maybe sooner. Where will our energy come from then? If fossil fuels are an energy source soon to be in our past, then biofuels may be the fuels of the future. Biofuels, however, are by no…

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The Power of Photosynthesis - The Carbon Cycle

Most of the energy we use is a result of photosynthesis; the process plants use to make food. During photosynthesis, plants use chlorophyll, a green pigment, to capture light energy from the Sun. The energy helps plants change water and carbon dioxide into glucose. Plants use glucose, a simple sugar, as food, or they convert the sugar to a starch and store it for later use. Carbon is the fo…

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Ethanol Fuel

Ethanol is an alcohol fuel made from the sugars found in plants. It is flammable and produces heat energy when burned. Ethanol factories produce ethanol from many types of biomass, especially corn and sugarcane. Farmers grow the biomass and sell it to processing plants. Processors convert the biomass to ethanol and sell it, mostly for use as a motor vehicle fuel. Ethanol is a common type of biofu…

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Big vehicles like trucks, buses, boats, and construction equipment typically have diesel engines. Diesel engines run on diesel fuel processed from crude oil, a fossil fuel. Biodiesel is a fuel for diesel engines made from vegetable oil or animal fats. Soybean oil and canola oil are two vegetable oils used to make biodiesel. Using biodiesel has many advantages over using petroleum diesel. For one,…

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acid rain (ASS-id-RAYN): polluted rain from gas released from burning fossil fuels agricultural (AG-ruh-KUL-chur): business of producing crops and raising animals algae (AL-jee): small plants that grow in water or damp areas carbon dioxide (kar-buhn dye-OK side): colorless, odorless gas chlorophyll (KLOR-uh-fil): green pigment in plants efficient (uh-FISH-uhnt): work without wasting energy emissi…

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