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Why do some things work on batteries and others work on outlets?
—Heal

Answer: Small, portable devices like phones, music players, and cameras are designed to run on batteries. It would not be practical to have to plug them in, because we use them while moving about. But bigger objects that require more power for longer amounts of time (such as kitchen appliances, TVs, washers, dryers, and computers) are designed to get their power from wall outlets because this is the best way to draw on large amounts of electrical energy over extended periods of time.

Who is building the infrastructure to recharge the electrical automobile now being built by GM and other manufacturers?
—Anonymous

Answer: This is an interesting question, as indeed, electrical vehicle sales are expected by some to grow by nearly 40% during this decade. Through its Transportation Electrification Initiative, the U.S. Department of Energy (DOE) has provided support to the companies ECOtality and ChargePoint America for developing both residential and public charging infrastructures, and in turn these companies are making publicly available the data they collect on user habits to help DOE improve the system as it grows. Other companies and organizations are also working nationwide to broaden the charging infrastructure to accommodate the anticipated surge of EVs on the road.

Why does electricity want to touch the ground?
—Jayda

Answer: It's just the nature of electricity to move from an area of higher voltage to an area of lower voltage, if given a path to travel there. The ground is simply the lowest-voltage area around, so if you give electricity a path to the ground, it will take it, no questions asked!

Why does electricity shock people?
—Cassie

Answer: If you touch electricity, it can shock you. Electricity can shock people because the human body is 60% water, and water is a good conductor of electricity. Electricity won’t shock you, however, if you follow the tips on this website and learn to use it safely.

Why do I need to unplug my cell phone charger?
—Alysse

Answer: Cell phone chargers are known as “energy vampires,” because they draw a lot of energy by being plugged in when phones are already charged or not even connected to them. In fact, only 5% of the power drawn by a cell phone charger is used to charge the phone. The other 95% is wasted when it is left plugged into the wall! To stop this energy waste, get yourself (and your family) in the habit of unplugging all chargers-including iPod chargers-when not in use.

What is an electromagnet?
—Grace

Answer: An electromagnet is a magnet in which the magnetic field is produced by a flow of electric current. It consists of a coil of copper wire wrapped around an iron core. You can change (or stop) the strength of an electromagnet by adjusting the amount of electricity flowing through it.

Why do we need electrical systems in schools?
—Heal

Answer: We need electrical systems in schools just like we need them in our homes and other types of buildings: to provide power to run lights, heating and cooling systems, and devices like computers, video monitors, and projectors.

Why can't you put anything that's metal in a toaster?
—Justice

Answer: Metal is an excellent conductor of electricity. If you put something metal, such as a fork, in a toaster, you could contact a live electrical part in the toaster. Electricity would travel through the metal fork into your arm, and since the human body is also good conductor of electricity, you would be shocked and could be seriously hurt.

What would happen if we put too much energy in a big electrical system?
—Heal

Answer: If too much electrical energy were sent into a big electrical system, such as at a mall, it would result in overloaded electrical circuits. Safety devices such as fuses and circuit breakers would cut power to these circuits to prevent a fire or other damage.

Where does all the energy in a school come from?
—Heal

Answer: The electrical energy that makes everything run in your school comes from the same place that all our buildings' electrical energy comes from. Electricity is generated in power plants and then flows at high voltages along overhead or underground power lines, and through transformers, where the voltage is reduced. From transformers (often housed in electrical substations), it travels through power lines and then along service wires into buildings such as those at your school.

How does the energy get from here to the solar panel?
—Justice

Answer: Energy travels directly from the sun into solar panels, which are special panels of solar cells, or modules, that capture sunlight and convert it directly into electricity. These panels are known as photovoltaic, or PV. (Photo is Greek for light, and voltaic pertains to electricity.) Perhaps what you're really asking is this: How does energy get from solar panels to here, for our use? One way is when several PV panels are grouped into solar arrays, which some buildings have on rooftops to provide energy for those buildings. The electricity produced by solar panels can be used right away, fed into the power grid for others to use, or stored in a battery so it is also available on cloudy days. Some solar panels contain tiny tubes filled with water that absorb heat from the sun. Placed on rooftops, these can supply hot water for individual buildings. Concentrated solar power can also be used to heat water into steam that spins turbines at electric power plants.

I have heard that planting trees saves energy. Why is that?
—Skyler

Answer: Trees planted on the south and west sides of your home will keep your house cooler in the summer because the shade they provide screens the sun's rays from hitting your house and heating it up. This means you won't have to make your air conditioning work quite so hard, thus saving energy.

How is electricity created with atoms?
—Nicole

Answer: Electricity isn't exactly created with atoms. It's the movement of electrons between atoms that generates electricity. In power plants various energy sources (such as fossil fuels, wind, or hydropower) are used to turn turbines. The turbines spin electromagnets that are surrounded by heavy coils of copper wire. The moving magnets cause the electrons in the copper wire to move from atom to atom, and this is what creates electricity.

I once saw a pair of shoes hanging from a power line. Why didn’t the shoes get burned up by the electricity in the line?
—Will

Answer: Shoes hanging on a power line don’t get burned for the same reason that birds standing on a power line don’t get shocked: they don’t give electricity a path to the ground, so electricity stays in the line and does not go through them. But if the shoes were to touch a power line and a power pole at the same time, they would provide a path to the ground and would get blasted with electric current. It wouldn’t be pretty!

By the way, if you ever see someone throwing shoes up onto a line, tell them to stop! The shoes can damage the power line, or someone trying to get the shoes down could be seriously shocked or even killed.

Is it true that cars could someday run on cow manure?
—Tyler

Answer: Yes! Manure can be made into a gas containing methane. (Methane is the same energy-rich gas found in natural gas.) Certain types of bacteria emit this gas as they consume manure collected in special air-free tanks. The mixture of gases produced in this way, called biogas, can then be used in some modified car engines instead of gasoline, or burned in a boiler to generate heat or electricity.

I have heard that landfills can be a source of energy. How does that work?
—Alya

Answer: Just like manure, other types of organic waste emit methane as they decompose—or rot—in the landfill. Landfills can collect and treat the methane and then sell it as a commercial fuel, or they can burn it to generate steam and electricity. Today, there are almost 400 gas energy landfill projects operating in the United States.

What kind of a difference does it really make to replace a regular light bulb with an energy-saving one?
—Anna

Answer: Replacing one incandescent light bulb with an energy-saving compact fluorescent bulb prevents about 1,000 pounds of carbon dioxide from being emitted to the atmosphere from power plants, and saves about $67 dollars in energy costs over the bulb’s lifetime.

Why didn’t Ben Franklin get killed when he tied a metal key to a kite string and flew the kite in a thunderstorm?
—Zachary

Answer: Ben Franklin’s famous key did give off an electric spark. But lucky for Franklin, the kite was just drawing small electrical charges from the air. If the kite had been struck by lightning, Franklin could have been killed!

How much energy is in a bolt of lightning?
—Sophie

Answer: One lightning strike can carry up to 30 million volts—as much electricity as 2.5 million car batteries.